cryptococcus neoformans is a fungal pathogen which causes severe infections in immunocompromised individuals , for example , aids patients and patients going through organ transplantation.1 
 c.  neoformans is surrounded by capsular polysaccharides ( cpss ) , primarily the glucuronoxylomannan ( gxm)polysaccharide comprising 9095  % of the total capsule mass . the structure of the gxm is believed to be built up of triads , that is , substituted (13 ) linked trisaccharide mannans , as depicted in figure  1 . glucuronic acid residues are linked to position  2 of the mannose backbone , together with a heterogeneous pattern of 2 and/or 4xylose substituents . the amount of xylose substitution is the major determinant for the serotyping , with serotype  b and c being the more substituted . gxm is also heterogeneously acetylated with the acetate positioned at the 6oh of the mannose backbone but not present in the residues carrying 4oxylose.2 the acetylation is believed to be important for virulence for serotypes  a and d.3 
  suggested structures of c.  neoformans gxm serotype triads . our main focus is on serotypes  a and d , which are the most common ones in human infections , but we are also interested in 4oxylosyl containing motifs usually attributed to serotypes  b and c , since these structures , owing to the large heterogeneity of the cps , are present in minor quantities also in cpss serotyped as a or d. furthermore , serotype  c structures have the lowest degree of acetylation , which should simplify structure  activity interpretation of immunological results . a building block synthetic strategy for serotype  a and d structures using 2osubstituted disaccharides ( i  iii , figure  2)4 , 5 , 6 , 7 , 8 , 9 has been developed , but the use of 2,4diosubstituted trisaccharide building blocks has not been investigated in detail . the syntheses of both the 2,4dioxyl ( iv , figure  2)10 and the 2oglca[4oxyl ] ( v , figure  2)6 , 11 substituted trisaccharide thioglycoside building blocks have been published , but only the former has been used in glycosylations and then only as a donor . the potential use of block  v as donor or as acceptor to form heavily branched 2,3,4trisubstituted mannose motifs has not been explored . 
  desired thioglycoside building blocks . r = persistent protecting group , orthoghonal to the acetyl group ; r = temporary protecting group , orthoghonal to r and acetyl groups . a slightly different approach to the one we are pursuing has been investigated by zhao and kong12 , 13 on the syntheses of nonacetylated methyl glycoside structures of serotype  b. these capsular polysaccharide fragments were prepared following a mixed convergentlinear strategy . in particular , the xylosesubstituted trisaccharide mannan backbone was constructed before , and the glucuronic acid ( glca ) was introduced in the final step . when the mannose residue involved in the glycosylation was at the nonreducing end in a hexasaccharide acceptor ( figure  3  a ) , no reaction was observed with methyl 2,3,4trioacetyl bromo or trichloroacetimidate glca donors.12 
  schematic representation of glca glycosylation of xylosesubstituted trisaccharide mannan backbone , reported previously.12 , 13 , 14 
  however , when the mannose residue was at the reducing end of the hexasaccharide acceptor ( figure  3  b ) , the glycosylation proceeded smoothly ( 78  % yield ) , affording the target nonacetylated heptasaccharide structural motif.13 noteworthy , this latter strategy failed when the same glycosylation was performed on serotype  c heptasaccharide acceptor ( figure  3 , c).14 the conflicting outcomes of glca glycosylation decrease the attractiveness of this strategy in the preparation of larger gxm fragments . herein , our recent efforts in the preparation of the orthogonally protected building block type  v are reported together with its use in the construction of larger spacercontaining acetylated part structures following a convergent approach . in our previous synthesis,6 building block  v was prepared with an allyl group as the temporary protecting group in position  3 . however , in light of results obtained in attempts to remove the allyl group on disaccharide thioglycosides , showing its incompatibility with the thioethyl group,9 the allyl group was changed into a naphthalenylmethyl protecting group ( nap ) in the new synthesis ( scheme  1 ) . reagents and conditions :  a )  nacnbh3 , hcl ( 1  m in et2o ) , thf , ph  12 , 20  c , 30  min , 93  % ; b )  tmsotf , ch2cl2 , aw300 ms , 78  c0  c , o / n , 70  % ; c )  1 . dowex h ionexchange resin , 80  % ; d )  tbdmscl , pyridine , dmap , 20  c , 4  h , 76  % ; e )  nah , bnbr , dmf , 0  c20  c , o / n , 77  % ; f )  tbaf trihydrate , thf , 20  c , 2  h , 96  % ; g )  1 )  tempo , baib , ch2cl2/h2o ( 2:1 ) , 20  c ; 2 )  cs2co3 , bnbr , dmf , 0  c20  c , 2  h , 60  % . starting from compound  1,7 the benzylidene ring was opened regioselectively with nacnbh3/hcl15 obtaining compound 4oh acceptor 2 in 93  % yield . the coupling of 2 and 3 
 16 was carried out using trimethylsilyl trifluoromethanesulfonate ( tmsotf ) in the presence of ( commercial ) acidwashed molecular sieves to prevent orthoester formation and afford compound  4 in 70  % yield . at this stage , benzoyl groups , which ensured the stereoselective course of the glycosylation , were removed and the primary oh was selectively protected by reaction with tertbutyldimethylsilyl chloride ( tbdmscl ) giving 6 in 61  % yield over two steps . the remaining hydroxy groups were perbenzylated ( 7 , 77  % ) before compound 8 was obtained in an almost quantitative yield ( 96  % ) by reaction with tetranbutylammonium fluoride ( tbaf ) . nmr analysis of compound  8 at 25  c in cdcl3 gave unexpected results , which included broad peaks in the h  nmr spectrum and even missing carbon peaks in the c  nmr spectrum ( figure  4 ) . a )  hc hsqc spectrum of compound  8 at 25  c ; b )  hc hsqc spectrum of compound  8 at 50  c ; the now visible anomeric cross peak is highlighted . by carrying out the nmr experiments at 50  c ( figure  4  b ) , sharper peaks ( h  nmr ) and expected peaks ( c  nmr ) were observed . in particular , the cross peak for c1 as well as the two anomeric carbons for c1 and c1 were visible . this behaviour is in agreement with hindered rotation for compound  8.17 interestingly , the nmrs of the related compounds  7 and 9 do not show this behaviour . final oxidation with the ( 2,2,6,6tetramethylpiperidin1yl)oxyl[bis(acetoxy)iodo]benzene ( tempobaib)18 system followed by benzylation of the crude ( cs2co3 , bnbr ) afforded the desired building block 9 in satisfactory 60  % yield . prepared trisaccharide 9 was tested in a dimethyl(methylthio)sulfonium trifluoromethansulfonate ( dmtst)promoted glycosylation with the spacercontaining derivative 10 
 10 ( scheme  2 ) and afforded linked tetrasaccharide 11 as the sole product in 95  % yield , demonstrating excellent donor properties of trisaccharide 9 to monosaccharide acceptors . reagents and conditions :  a )  dmtst , et2o , 0  c20  c , 1.5  h , 95  % for 11 , 79  % for 14 ; b )  ddq , ch2cl2/h2o ( 10:1 ) , 20  c , 60  min , 74  % ; c )  h2/pdc ( 30  bar ) , etoac , h2o , acoh , 67  % . the removal of the naphthalenylmethyl protecting group by reaction with 2,3dichloro5,6dicyano1,4benzoquinone ( ddq ) in a mixture of dichloromethane / water proceeded in 74  % yield to obtain acceptor 12 ready for testing the possibility of obtaining 2,3,4trioglycosylated structures . thus , acceptor 12 was reacted with disaccharide thioglycoside 13 
 9 again using dmtst as promoter . satisfactorily , hexasaccharide 14 was obtained with complete selectivity and in high yield ( 79  % ) and was then completely deprotected by means of hydrogenolysis to afford 15 in 67  % yield . this rather unusual gxm structural motif was reported recently by nimrichter et  al.19 who characterised a substituted triad from encapsulated cells that had only been described in polysaccharide fractions from a hypocapsular mutant . nmr data for 15 are in good agreement with the one reported for the polysaccharide : anomeric reported values : 4.45  ppm ( glca ) , 4.35  ppm ( 2oxyl ) , 4.25  ppm ( 4oxyl ) ; found for 15 4.47  ppm ( glca ) , 4.40  ppm ( 2oxyl ) , 4.31  ppm ( 4oxyl ) . a more complex acceptor than the monosaccharide 10 was then prepared to further investigate the donor properties of trisaccharide 9 ( scheme  3 and 4 ) . spacerequipped acceptor 17 , obtained from 16 
 10 in 88  % yield , was coupled with trichloroacetimidate donor 3 
 16 using tertbutyldimethylsilyl trifluoromethanesulfonate ( tbdmsotf ) in the presence of acidwashed molecular sieves yielding disaccharide 18 in 86  % yield . benzoyl groups , again utilised for their anchimeric assistance in the glycosylation reaction , were exchanged for benzyl groups affording 20 in 77  % yield over two steps . / bh3 
 20 to afford the opposite regioselectivity to compound  1 , giving the 6oh compound  21 ( 76  % ) , which was either acetylated ( 22 , 93  % ) or benzylated ( 23 , 95  % ) . the 6oacetyl disaccharide 22 was then chosen for the preparation of a tetrasaccharide acceptor for the consecutive construction of the spacercontaining c.  neoformans serotype  b heptasaccharide triad motif which followed our standard sequence of reactions : nap removal followed by dmtstpromoted glycosylation ( scheme  4 ) . reagents and conditions :  a )  bu2sno , bu4nbr , napbr , toluene , reflux , 3  h , 88  % ; b )  tbdmsotf , ch2cl2 , aw300 ms , 78  c20  c , o / n , 86  % ; c )  1 . dowex h ionexchange resin , 86  % ; d )  nah , bnbr , dmf , 0  c20  c , 3  h , 90  % ; e )  bu2botf , bh3 ( 1  m in thf ) , ch2cl2 , 0  c , 90  min , 76  % ; f )  ac2o , pyridine , 20  c , 3  h , 93  % ; g )  nah , bnbr , dmf , 0  c20  c , 2  h , 95  % . reagents and conditions :  a )  ddq , ch2cl2/h2o ( 10:1 ) , 20  c , 60  min , 73  % for 24 , 80  % for 27 ; b )  dmtst , et2o , 0  c20  c , 3.5  h , 85  % . the first reaction gave disaccharide acceptor 24 in 73  % yield , while the glycosylation with 25 
 9 afforded tetrasaccharide 26 in 85  % yield , which was in turn converted into the new acceptor 27 ( 80  % yield ) . as mentioned in the introduction , acetates are heterogenously present on the 6oh of mannose residues if no 4oxylose substituents are present . by choosing the correct combination from the set of thioglycoside donors ( 13 and 25 ) and spacercontaining acceptors ( 24 and the one that can be prepared from 23 after nap removal ) , and by following the same sequence of reactions reported in scheme  4 , all possible acetylation patterns on the tetrasaccharide motif can be obtained , permitting following investigation into the effect of the acetylation pattern on the immune response . finally , building block 9 was used in the glycosylation reaction with 27 to prepare the desired structural motif ( scheme  5 ) . reagents and conditions :  a )  dmtst , et2o , dmtst , et2o , 0  c20  c , 3.5  h , 83  % ; b )  ddq , ch2cl2/tbuoh ( 10:1 ) , 20  c , 1.5  h , 68  % . the reaction proceeded smoothly ( 83  % ) and permitted , for the first time , the synthesis of monoacetyl heptasaccharide 28 . this result , together with the preparation of tetrasaccharide 11 , confirmed the versatility of the proposed convergent strategy which allows for installation of the glca containing trisaccharide in every position of the mannan triad thus overcoming the problems encountered previously with different strategies . derivative 28 could be completely deprotected by hydrogenolysis , as shown for 14 , and used to prepare a candidate vaccine after conjugation with an immunogenic protein , or could be employed as an acceptor after removal of the nap group ( 29 , 68  % ) , to further elongate the gxm fragment . in conclusion , an efficient synthesis of a glcacontaining trisaccharide thioglycoside building block corresponding to cryptococcus neoformans serotype  b and c glucuronoxylomannan ( gxm ) oligosaccharide structure has been developed . the naphthalenylmethyl ( nap)protected building block was shown to be a most efficient glycosyl donor to both monosaccharide and more complex acceptors in dimethyl(methylthio)sulfoniumtrifluoromethansulfonate ( dmsts)promoted glycosylation reactions which proceeded with high yields and complete selectivity . subsequent removal of the 2nap temporary protecting group converted obtained saccharides into new acceptors , which were shown to work well in following glycosylation reactions allowing effective construction of heavily branched 2,3,4subtituted motifs . thus , the presented strategy permitted the preparation of both a hexasaccharide ( 14 ) and a serotype b heptasaccharide structural motif , and the results demonstrate the possible synthesis of any c.  neoformans gxm structure from the various available mono , di , and trisaccharide building blocks . general : thinlayer chromatography ( tlc ) was carried out on precoated 60 f254 silica gel alumina plates ( merck ) using uv light and/or 8  % h2so4 and/or amcsolution ( ammonium molybdate , cerium ( iv ) sulphate , 10  % h2so4 [ 5:0.1:100 , w / w / v ] for visualisation . flash column chromatography was performed on silica gel ( merck , pore size 60   , particle size 4063  m ) . nmr spectra were recorded in cdcl3 ( internal me4si d=0.00  ppm ) at 25  c on a varian instrument ( 500  mhz for h and 125  mhz for c or 600  mhz for h and 150  mhz for c , vnmrs 500  mhz or 600  mhz , palo alto , usa ) . highresolution mass spectrometry ( hrms ) spectra were recorded on a micromass lct instrument ( waters , milford , usa ) using electrospray ionisation ( esi ) in either the positive or negative modes . optical rotations were measured with a perkinelmer 343 polarimeter ( waltham , usa ) at the sodium dline ( 589  nm ) at 20  c using a 1  dm cell . organic phases were dried over mgso4 before evaporation , which was performed under reduced pressure at temperatures not exceeding 40  c . sodium cyanoborohydride ( 223  mg , 3.56  mmol ) was added to a solution of acetal 1 ( 612  mg , 0.59  mmol ) in dry tetrahydrofuran ( thf , 25  ml ) containing crushed molecular sieves ( 3   , 150  mg ) . a 1  m solution of hcl in et2o ( 9.0  ml , 9.0  mmol ) the reaction mixture was stirred until no starting material was detected by tlc ( toluene / etoac , 6:1 ) . after 30  min , et3n ( 2.5  ml , 17.80  mmol ) was added , followed by dropwise addition of meoh ( 10  ml ) . ch2cl2 ( 20  ml ) was added , the solids were removed by filtration through a short pad of celite , concentrated in vacuo , and then redissolved and coevaporated with meoh ( 350  ml ) . purification by flash column chromatography ( sio2 , 100  ml , 4.5  cm , toluenetoluene / etoac , 96:493:790:1087:1385:1580:2075:25 ) gave 2 ( 571  mg , 93  % ) as a colourless , amorphous solid : r 
 f=0.32 ( toluene / etoac , 6:1 ) ; [ ]d 
 + 6.7 ( c 1.0 , chcl3 ) ; h  nmr ( 500  mhz , cdcl3 ) : =7.967.88 ( m , 6  h ) , 7.877.81 ( m , 2  h ) , 7.797.66 ( m , 4  h ) , 7.547.38 ( m , 7  h ) , 7.367.32 ( m , 2  h ) , 7.317.14 ( m , 11  h ) , 5.93 ( t , j 9.7 , 1  h ) , 5.705.61 ( m , 1  h ) , 5.27 ( d , j 1.0 , 1  h ) , 5.01 ( d , j 7.9 , 1  h ) , 4.91 ( d , j 11.5 , 1  h ) , 4.65 ( dd , j 3.1 , j 12.1 , 1  h ) , 4.57 ( d , j 11.5 , 1  h ) , 4.48 ( dd , j 5.7 , j 12.1 , 1  h ) , 4.32 ( dd , j 1.7 , j 2.9 , 1  h ) , 4.26 ( s , 2  h ) , 4.214.15 ( m , 1  h ) , 3.96 ( ddd , j 3.3 , j 6.6 , j 9.7 , 1  h ) , 3.81 ( t , j 9.4 , 1  h ) , 3.68 ( dd , j 3.1 , j 9.2 , 1  h ) , 3.58 ( dd , j 3.3 , j 10.7 , 1  h ) , 3.27 ( dd , j 6.6 , j 10.7 , 1  h ) , 2.552.38 ( m , 3  h ) , 1.15  ppm ( t , j 7.4 , 3  h ) ; c  nmr ( 125  mhz , cdcl3 ) : =166.2 , 166.0 , 165.3 , 164.9 , 138.5 , 135.2 , 133.6 , 133.4 , 133.3 , 133.2 , 133.2 , 133.1 , 130.0 , 129.9 , 129.9 , 129.8 , 129.7 , 129.6 , 129.0 , 128.9 , 128.6 , 128.5 , 128.4 , 128.4 , 128.3 , 128.1 , 127.8 , 127.5 , 127.5 , 127.1 , 126.2 , 126.1 , 126.0 , 99.8 , 81.2 , 77.9 , 75.5 , 73.4 , 73.0 , 72.7 , 71.9 , 71.86 , 70.9 , 70.9 , 69.9 68.1 , 63.4 , 25.4 , 14.8 ; hrms ( esi ) : [ mh ] 
 m / z calcd for c60h55o14s : 1031.3313 , found : 1031.3279 ; anal . calcd for c60h55o14s : c 69.75 , h 5.46 , s 3.10 , found : c 69.43 , h 5.43 , s 3.28 . . a catalytic amount of tmsotf ( 20  l , 11  mol ) was added to a solution of donor 3 
 16 ( 88  mg , 0.145  mmol ) and acceptor 2 ( 116  mg , 0.113  mmol ) in dry ch2cl2 ( 5  ml ) containing crushed molecular sieves ( aw300 , 40  mg ) kept at 78  c in an atmosphere of nitrogen . the temperature was then allowed to rise to 20  c overnight ( tlc , tolueneetoac , 6:1 ) . the reaction mixture was neutralised with et3n ( 16  l , 0.113  mmol ) , the solids were removed by filtration , and the filtrate was concentrated in vacuo to a yellowish foam . purification by flash column chromatography ( sio2 , 100  ml , 4.5  cm , toluenetoluene / toac , 98:296:494:6 92:890:1088:1286:14 ) gave 4 ( 118  mg , 70  % ) as a colourless foam : r 
 f=0.46 ( toluene / etoac , 9:1 ) ; [ ]d 
 + 5.6 ( c 1.0 , chcl3 ) ; h  nmr ( 500  mhz , cdcl3 ) : =7.937.83 ( m , 14  h ) , 7.777.69 ( m , 4  h ) , 7.567.42 ( m , 7  h ) , 7.397.19 ( m , 20  h ) , 7.107.03 ( m , 2  h ) , 5.90 ( t , j 9.7  hz , 1  h ) , 5.715.62 ( m , 2  h ) , 5.53 ( t , j 8.2  hz , 1  h ) , 5.26 ( dd , j 6.5  hz , j 8.2  hz , 1  h ) , 5.20 ( d , j 2.9  hz , 1  h ) , 5.16 ( td , j 4.9  hz , j 8.1  hz , 1  h ) , 5.02 ( d , j 7.9  hz , 1  h ) , 4.94 ( d , j 11.3  hz , 1  h ) , 4.73 ( d , j 6.2  hz , 1  h ) , 4.68 ( d , j 11.4  hz , 1  h ) , 4.61 ( dd , j 3.1  hz , j 12.1  hz , 1  h ) , 4.44 ( dd , j 5.2  hz , j 12.1  hz , 1  h ) , 4.20 ( bs , 1  h ) , 4.154.09 ( m , 3  h ) , 4.013.88 ( m , 4  h ) , 3.34 ( dd , j 1.9  hz , j 10.8  hz , 1  h ) , 3.27 ( dd , j 5.9  hz , j 10.9  hz , 1  h ) , 3.02 ( dd , j 8.3  hz , j 12.1  hz , 1  h ) , 2.442.30 ( m , 2  h ) , 1.06  ppm ( t , j 7.4  hz , 1  h ) ; c  nmr ( 125  mhz , cdcl3 ) : =166.1 , 165.9 , 165.5 , 165.5 , 165.3 , 165.2 , 164.9 , 138.6 , 135.6 , 133.5 , 133.4 , 133.3 , 133.3 , 133.3 , 133.2 , 133.1 , 133.0 , 130.0 , 130.0 , 129.9 , 129.9 , 129.9 , 129.8 , 129.7 , 129.5 , 129.4 , 129.4 , 129.0 , 128.9 , 128.5 , 128.5 , 128.5 , 128.4 , 128.4 , 128.2 , 128.2 , 128.0 , 127.8 , 127.5 , 127.4 , 127.2 , 126.6 , 126.1 , 125.9 , 100.8 , 100.6 , 81.3 , 77.3 , 77.1 , 76.2 , 73.1 , 72.9 , 72.6 , 72.2 , 71.9 , 71.5 , 71.4 ( 2c ) , 69.8 , 69.5 , 69.3 , 63.3 , 61.9 , 25.2 , 14.7  ppm ; hrms ( esi ) : [ m+na ] 
 m / z calcd for c86h76o21nas : 1499.4498 , found : 1499.4547 ; anal . calcd for c86h76o21s : c 69.91 , h 5.18 , s 2.17 , found : c 69.75 , h 5.28 , s 2.43 . ethyl dglucopyranosyl(12)[dxylopyranosyl(14)]6obenzyl3o(2naphthalenylmethyl)1thiodmannopyranoside  ( 5 ) . a catalytic amount of sodium methoxide ( 75  mg , 1.38  mmol ) was added to a solution of 4 ( 4.10  g , 2.77  mmol ) in dry meoh ( 150  ml ) . the mixture was stirred at 20  c overnight ( tlc , ch2cl2meoh , 9:1 ) . after complete conversion , dowex ( h ) acidic ionexchange resin was added for neutralisation , the resin was filtered off , washed with meoh ( 30  ml ) , and the filtrate was concentrated in vacuo . purification by flash column chromatography ( sio2 , 600  ml , 7.5  cm , dcmdcm / meoh , 95:590:1088:1286:1484:1683:1782:18 ) gave 5 ( 1.68  g , 80  % ) as a colourless , amorphous solid : r 
 f=0.13 ( ch2cl2/meoh , 9:1 ) ; [ ]d 
 + 45.6 ( c 1.0 , meoh ) ; h  nmr ( 600  mhz , dmso )  7.93 ( 1  h , s ) , 7.887.84 ( 1  h , m ) , 7.81 ( m , 2  h ) , 7.56 ( dd , 1.6  hz , j 8.5  hz , 1  h ) , 7.487.43 ( m , 2  h ) , 7.437.28 ( m , 4  h ) , 7.277.23 ( m , 1  h ) , 5.40 ( d , j 2.0  hz , 1  h ) , 5.10 ( d , j 4.8  hz , 1  h ) , 4.944.83 ( m , 5  h ) , 4.694.60 ( m , 2  h ) , 4.53 ( d , j 11.9  hz , 1  h ) , 4.44 ( d , j 11.9  hz , 1  h ) , 4.39 ( t , j 5.6  hz , 1  h ) , 4.33 ( d , j 7.8  hz , 1  h ) , 4.22 ( d , j 7.4  hz , 1  h ) , 4.19 ( t , j 2.8  hz , 1  h ) , 4.003.90 ( m , 2  h ) , 3.86 ( dd , j 4.8  hz , j 11.1  hz , 1  h ) , 3.75 ( dd , j 1.6  hz , j 11.2  hz , 1  h ) , 3.733.64 ( m , 2  h ) , 3.61 ( dd , j 3.4  hz , j 8.3  hz , 1  h ) , 3.423.35 ( m , 1  h ) , 3.323.27 ( m , 1  h ) , 3.193.09 ( m , 2  h ) , 3.092.96 ( m , 4  h ) , 2.88 ( dd , j 10.2  hz , j 11.5  hz , 1  h ) , 2.642.49 ( m , 2  h ) , 1.16  ppm ( t , j 7.4  hz , 3  h ) ; c  nmr ( 125  mhz , dmso ) : =138.6 , 136.6 , 132.8 , 132.4 , 128.2 , 127.6 , 127.5 , 127.4 , 127.3 , 126.2 , 126.0 , 125.9 , 125.6 , 103.9 , 101.6 , 81.8 , 77.2 , 76.8 , 76.7 , 76.6 , 74.7 , 74.1 , 73.9 , 73.1 , 72.2 , 71.7 , 70.3 , 70.3 , 69.7 , 68.8 , 65.9 , 61.5 , 24.5 , 14.9  ppm ; hrms ( esi ) : [ mh ] 
 m / z calcd for c37h47o14s : 747.2687 , found : 747.2702 . 
 ethyl 6otertbutyldimethylsilyldglucopyranosyl(12)[dxylopyranosyl(14)]6obenzyl3o(2naphthalenylmethyl)1thiodmannopyranoside  ( 6 ) . tertbutyldimethylchlorosilane ( 82  mg , 0.55  mmol ) and a catalytic amount of dmap ( 1  mg , 8  mol ) were added to a solution of 5 ( 273  mg , 0.36  mmol ) in dry pyridine ( 10  ml ) , and the mixture was stirred at 20  c for 4  h. the progress of the reaction was followed by tlc ( dcm / meoh , 9:1 ) . the mixture was concentrated in vacuo , and then redissolved and coevaporated with toluene ( 330  ml ) ( water bath temperature of rotary evaporator : < 30  c ) . purification by flash column chromatography ( sio2 , dcmdcm / meoh , 95:594:693:792:891:990:10 ) gave 6 ( 240  mg , 76  % ) as colourless , amorphous solid : r 
 f=0.35 ( ch2cl2/meoh , 9:1 ) ; [ ]d 
 + 31.5 ( c 0.89 , meoh ) ; h  nmr ( 500  mhz , cdcl3 ) : =7.827.74 ( m , 4  h ) , 7.53 ( d , j 8.5  hz , 1  h ) , 7.477.39 ( m , 2  h ) , 7.357.19 ( m , 5  h ) , 5.32 ( s , 1  h ) , 4.85 ( d , j 11.5  hz , 1  h ) , 4.78 ( d , j 11.5  hz , 1  h ) , 4.59 ( d , j 12.0  hz , 1  h ) , 4.51 ( d , j 12.0  hz , 1  h ) , 4.434.36 ( m , 2  h ) , 4.314.19 ( m , 3  h ) , 4.134.07 ( m , 2  h ) , 3.933.77 ( m , 6  h ) , 3.733.64 ( m , 3  h ) , 3.553.40 ( m , 4  h ) , 3.353.26 ( m , 3  h ) , 3.00 ( t , j 10.6  hz , 1  h ) , 2.89 ( bs , 1  h ) , 2.612.46 ( m , 2  h ) , 1.20 ( t , j 7.4  hz , 1  h ) , 0.84 ( s , 9  h ) , 0.00 ( s , 3  h ) , 0.00  ppm ( s , 3  h ) ; c  nmr ( 125  mhz , cdcl3 ) : =137.6 , 134.8 , 133.3 , 133.2 , 128.6 , 128.2 , 128.2 , 128.1 , 128.0 , 127.8 , 127.7 , 126.7 , 126.2 , 126.1 , 103.2 , 100.7 , 82.6 , 77.0 , 76.3 , 76.1 , 75.6 , 74.2 , 74.0 , 73.7 , 73.5 , 72.3 , 72.2 , 72.0 , 71.5 , 69.7 , 68.7 , 65.6 , 64.3 , 25.9 , 25.6 , 18.3 , 15.0 , 5.3 , 5.4  ppm ; hrms ( esi ) : [ mh ] 
 m / z calcd for c43h61o14ssi : 861.3551 , found : 861.3558 
 ethyl 2,3,4triobenzyl6otertbutyldimethylsilyldglucopyranosyl(12)[2,3,4triobenzyldxylopyranosyl(14)]6obenzyl3o(2naphthalenylmethyl)1thiodmannopyranoside  ( 7 ) . nah ( 100  mg , 2.49  mmol , 60  % oil dispersion ) was washed with pentane ( 310  ml ) prior to use . nah was added portionwise to a solution of 6 ( 239  mg , 0.27  mmol ) in dry dmf ( 10  ml ) at 0  c in an atmosphere of nitrogen . after 15  min , benzyl bromide ( 236  l , 2.00  mmol ) was added dropwise at 0  c under vigorous stirring . the temperature was then allowed to rise to 20  c overnight ( tlc , toluene / etoac , 9:1 ) . after complete consumption of the starting material , residual nah was quenched with meoh ( 1  ml ) , and then with h2o ( 50  ml ) . the resulting mixture was extracted once with etoac ( 40  ml ) , the layers were separated , and the organic layer was washed with brine ( 140  ml ) , dried over mgso4 , and concentrated in vacuo . purification by flash column chromatography ( sio2 , toluenetoluene / etoac , 97:394:692:891:9 ) gave 7 ( 300  mg , 77  % ) as a colourless syrup . r 
 f=0.61 ( toluene / etoac , 9:1 ) ; [ ]d 
 + 29.3 ( c 1.0 , chcl3 ) ; h  nmr ( 500  mhz , cdcl3 ) : =7.89 ( s , 1  h ) , 7.857.74 ( m , 3  h ) , 7.62 ( d , j 9.7  hz , 1  h ) , 7.497.13 ( m , 35  h ) , 7.107.02 ( m , 2  h ) , 5.47 ( d , j 2.1  hz , 1  h ) , 5.14 ( d , j 10.4  hz , 1  h ) , 5.06 ( d , j 12.4  hz , 1  h ) , 4.94 ( d , j 11.0  hz , 1  h ) , 4.874.69 ( m , 7  h ) , 4.66 ( m , 2  h ) , 4.574.50 ( m , 3  h ) , 4.384.22 ( m , 5  h ) , 4.084.02 ( m , 1  h ) , 3.923.75 ( m , 5  h ) , 3.683.51 ( m , 5  h ) , 3.43 ( t , j 8.9  hz , 1  h ) , 3.373.28 ( m , 2  h ) , 2.90 ( dd , j 10.1  hz , j 11.6  hz , 1  h ) , 2.682.54 ( m , 2  h ) , 1.26 ( t , j 7.4  hz , 3  h ) , 0.85 ( s , 9  h ) , 0.01 ( s , 3  h ) , 0.00  ppm ( s , 3  h ) ; c  nmr ( 126  mhz , cdcl3 ) : =138.9 , 138.8 , 138.8 , 138.7 , 138.4 , 138.4 , 138.3 , 136.3 , 133.4 , 133.0 , 129.1 , 129.0 , 128.5 , 128.4 , 128.4 , 128.2 , 128.2 , 128.2 , 128.0 , 128.0 , 127.9 , 127.8 , 127.8 , 127.8 , 127.7 , 127.6 , 127.6 , 127.5 , 127.4 , 126.8 , 126.6 , 125.9 , 125.6 , 103.4 , 102.0 , 85.0 , 84.1 , 82.4 , 81.8 , 78.3 , 77.5 , 76.4 , 76.3 , 75.7 , 75.5 , 75.4 , 75.0 , 75.0 , 74.9 , 74.6 , 73.0 , 72.9 , 71.9 , 71.1 , 69.0 , 63.6 , 62.7 , 26.2 , 26.1 , 25.5 , 18.4 , 15.0 , 5.1 , 5.2  ppm ; hrms ( esi ) : [ m+na ] 
 m / z calcd for c85h98o14nassi : 1425.6344 , found : 1425.6320 . 
 ethyl 2,3,4triobenzyldglucopyranosyl(12)[2,3,4triobenzyldxylopyranosyl(14)]6obenzyl3o(2naphthalenylmethyl)1thiodmannopyranoside  ( 8) . tbaf trihydrate ( 52  mg , 0.16  mmol ) was added to a solution of 7 ( 153  mg , 0.11  mmol ) in thf ( 5  ml ) , and the mixture was stirred at 20  c for 2  h ( tlc , toluene / etoac , 9:1 ) . after complete consumption of the starting material , the reaction mixture was concentrated in vacuo . purification by flash column chromatography ( sio2 , toluenetoluene / etoac , 93:790:1087:1384:1681:1978:2275:25 ) gave 8 ( 135  mg , 96  % ) as a colourless , amorphous solid : r 
 f=0.39 ( toluene / etoac , 6:1 ) ; [ ]d 
 + 34.5 ( c 0.42 , chcl3 ) ; h  nmr ( 500  mhz , cdcl3 ) : =7.847.77 ( m , 4  h , har ) , 7.567.54 ( m , 1  h , har ) , 7.487.44 ( m , 2  h , har ) , 7.387.36 ( m , 2  h , har ) , 7.327.20 ( m , 31  h , har ) , 7.127.11 ( m , 2  h , har ) , 5.37 ( d , 1  h , j 3.4  hz , h1 ) , 5.09 ( d , 1  h , j 10.4  hz , phch 
 2 ) , 4.93 ( d , 1  h , j 11.1  hz , phch 
 2 ) , 4.904.84 ( abq , 2  h , phch 
 2 ) , 4.824.70 ( m , 6  h , phch 
 2 ) , 4.634.50 ( m , 5  h , h1 , phch 
 2 ) , 4.354.26 ( m , 3  h , h1 , phch 
 2 ) , 4.17 ( m , 1  h , h4 ) , 4.09 ( m , 1  h , h2 ) , 4.044.02 ( m , 1  h , h5 ) , 3.92 ( m , 1  h , h3 ) , 3.783.73 ( m , 3  h , h6a , h6a , h5a ) , 3.633.49 ( m , 5  h , h6b , h2 , h3 , h6b , h4 ) , 3.433.39 ( m , 2  h , h4 , h3 ) , 3.333.29 ( m , 1  h , h5 ) , 3.27 ( t , 1  h , j 8.4  hz , h2 ) , 2.862.80 ( m , 1  h , h5b ) , 2.692.56 ( m , 2  h , sch 
 2ch3 ) , 1.26  ppm ( t , 3  h , j 7.4  hz , sch2ch 
 3 ) ; c  nmr ( 125  mhz , cdcl3 ) :  138.7 , 138.7 , 138.5 , 138.5 , 138.3 ( 2c ) , 138.0 , 136.1 , 133.2 , 133.0 ( car , quart ) , 128.8 , 128.44 , 128.40 , 128.33 , 128.28 , 128.22 , 128.21 , 128.17 , 128.1 , 128.0 , 127.9 , 127.83 , 127.78 , 127.76 , 127.7 , 127.6 , 127.51 , 127.47 , 127.4 , 126.7 , 126.1 , 125.8 ( car ) , 104.1 ( c1 ) , 103.2 ( c1 ) , 84.5 ( c3 ) , 84.0 ( c3 ) , 82.2 ( 2c , c1 , c2 ) , 81.7 ( c2 ) , 78.0 ( c4 ) , 77.8 ( c2 ) , 77.6 ( c4 ) , 77.0 ( c3 ) , 75.6 ( phch2 ) , 75.4 ( phch2 ) , 75.4 ( c5 ) , 75.1 ( phch2 ) , 75.0 ( phch2 ) , 74.8 ( phch2 ) , 73.0 ( phch2 ) , 73.0 ( phch2 ) , 72.4 ( napch2 ) , 72.0 ( c5 ) , 69.0 ( c6 ) , 63.6 ( c5 ) , 62.2 ( c6 ) , 25.4 ( sch2ch3 ) , 15.0  ppm ( sch2 
 ch3 ) . the signal of c4 could not be observed ; hrms ( esi ) : [ m+na ] 
 m / z calcd for c79h84o14nas : 1311.5479 , found : 1311.5487 . tempo ( 2  mg , 13  mol ) and baib ( 300  mg , 0.93  mmol ) were added to a vigorously stirred solution of 8 ( 116  mg , 90  mol ) in ch2cl2/h2o ( 12  ml , 3:1 ) , and the mixture was stirred at 20  c for 4  h. the progress of the reaction was carefully monitored by tlc ( toluene / etoac , 9:1 ) . the resulting mixture was extracted once with etoac ( 20  ml ) , the layers were separated , and the organic layer was washed with brine ( 110  ml ) , dried over mgso4 , and concentrated in vacuo . cs2co3 ( 57  mg , 0.17  mmol ) was added to a solution of the crude in dry dmf ( 3  ml ) at 20  c . after 15  min , benzyl bromide ( 22  l , 0.18  mmol ) was added dropwise at 0  c . the temperature was then allowed to rise to 20  c over 16  h ( tlc , toluene / etoac 9:1 ) . after complete consumption of the starting material , water ( 10  ml ) was added , and the resulting mixture was extracted with et2o ( 215  ml ) , the layers were separated , and the organic layer was dried over mgso4 , and concentrated in vacuo . purification by flash column chromatography ( sio2 , toluenetolueneetoac , 70:30 ) gave 9 ( 75  mg , 60  % ) as a pale yellow syrup : r 
 f=0.45 ( toluene / etoac , 9:1 ) ; [ ]d 
 + 31.7 ( c 1.0 , chcl3 ) ; h  nmr ( 500  mhz , cdcl3 ) : =7.847.77 ( m , 3  h ) , 7.74 ( d , j 8.4  hz , 1  h ) , 7.596.97 ( m , 43  h ) , 5.39 ( s , 1  h ) , 5.11 ( d , j 10.1  hz , 1  h ) , 5.075.00 ( m , 2  h ) , 4.924.85 ( m , 2  h ) , 4.844.77 ( m , 2  h ) , 4.774.69 ( m , 4  h ) , 4.654.60 ( m , 2  h ) , 4.554.50 ( m , 2  h ) , 4.484.44 ( m , 2  h ) , 4.37 ( d , j 7.5  hz , 1  h ) , 4.314.24 ( m , 2  h ) , 4.21 ( s , 2  h ) , 4.05 ( dd , j 3.8  hz , j 9.6  hz , 1  h ) , 3.94 ( d , j 9.8  hz , 1  h ) , 3.883.74 ( m , 4  h ) , 3.673.53 ( m , 4  h ) , 3.43 ( t , j 8.9  hz , 1  h ) , 3.333.29 ( m , 1  h ) , 2.922.87 ( m , 1  h ) , 2.652.54 ( m , 2  h ) , 1.25  ppm ( t , j 7.4  hz , 3  h ) ; c  nmr ( 125  mhz , cdcl3 ) : =168.1 , 138.8 , 138.8 , 138.7 , 138.5 , 138.4 , 138.3 , 138.0 , 136.2 , 135.1 , 133.4 , 133.1 , 129.3 , 128.8 , 128.6 , 128.6 , 128.5 , 128.5 , 128.4 , 128.4 , 128.3 , 128.2 , 128.1 , 128.0 , 128.0 , 127.9 , 127.9 , 127.8 , 127.8 , 127.8 , 127.7 , 127.7 , 127.5 , 127.5 , 127.4 , 126.8 , 126.6 , 125.9 , 125.7 , 103.5 , 102.8 , 84.2 , 84.1 , 82.5 , 82.0 , 81.1 , 79.0 , 78.5 , 76.6 , 76.3 , 75.8 , 75.6 , 75.2 , 75.2 , 75.1 , 74.9 , 74.4 , 73.0 , 73.0 , 72.0 , 71.5 , 68.9 , 67.4 , 63.7 , 25.7 , 15.1  ppm ; hrms ( esi ) : [ m+na ] 
 m / z calcd for c86h88o15nas : 1415.5742 , found : 1415.5712 . 2azidoethyl ( benzyl 2,3,4triobenzyldglucopyranosyluronate)(12)[2,3,4triobenzyldxylopyranosyl(14)]6obenzyl3o(2naphthalenylmethyl)dmannopyranosyl(13)2,4,6triobenzyldmannopyranoside  ( 11 ) . a mixture of 10 ( 10  mg , 19.3  mol ) , 9 ( 40  mg , 29  mol ) , and crushed molecular sieves ( 4   , 20  mg ) in dry et2o ( 2  ml ) was stirred at 20  c for 30  min . the reaction mixture was cooled to 0  c , freshly prepared dmtst ( 15  mg , 60  mol ) was added , and the reaction mixture was stirred at 0  c for 30  min . the progress of the reaction was carefully monitored by tlc ( toluene / etoac , 9:1 ) . the cooling bath was removed and stirring was continued at 20  c for 1  h. et2o ( 5  ml ) was added , and the reaction was quenched with et3n ( 50  l ) at 0  c . the solids were removed by filtration through a pad of celite , and the filtrate was concentrated in vacuo . purification by flash column chromatography ( sio2 , toluene / etoac , 97:370:30 ) gave 11 ( 34  mg , 95  % ) as a colourless syrup : r 
 f=0.56 ( toluene / etoac , 9:1 ) ; [ ]d 
 + 7.5 ( c 1.0 , chcl3 ) ; h  nmr ( 600  mhz , cdcl3 ) : =7.77 ( s , 1  h ) , 7.727.63 ( m , 3  h ) , 7.53 ( d , j 8.4 , hz , 1  h ) , 7.416.98 ( m , 57  h ) , 5.20 ( d , j 1.7  hz , 1  h ) , 5.08 ( d , j 10.5  hz , 1  h ) , 5.054.99 ( m , 2  h ) , 4.864.76 ( m , 4  h ) , 4.764.34 ( m , 16  h ) , 4.304.15 ( m , 4  h ) , 4.11 ( dd , j 9.5 , 3.1  hz , 1  h ) , 4.06 ( d , j 7.8  hz , 1  h ) , 4.013.89 ( m , 3  h ) , 3.903.39 ( m , 15  h ) , 3.343.26 ( m , 3  h ) , 3.22 ( ddd , j 13.2 , 6.1 , 3.7  hz , 1  h ) , 2.93  ppm ( dd , j 11.9 , 9.8  hz , 1  h ) ; c  nmr ( 151  mhz , cdcl3 ) : =168.2 , 138.8 , 138.8 , 138.7 , 138.7 , 138.5 , 138.4 , 138.4 , 138.4 , 138.4 , 138.4 , 136.4 , 135.2 , 133.4 , 133.0 , 129.2 , 128.8 , 128.7 , 128.6 , 128.5 , 128.5 , 128.4 , 128.4 , 128.4 , 128.3 , 128.2 , 128.2 , 128.1 , 128.0 , 127.9 , 127.8 , 127.8 , 127.8 , 127.7 , 127.6 , 127.6 , 127.6 , 127.6 , 127.5 , 127.4 , 127.3 , 126.9 , 126.8 , 126.8 , 125.9 , 125.7 , 103.7 ( j 
 ch 161  hz ) , 103.2 ( j 
 ch 162.5  hz ) , 99.7 ( j 
 ch 172  hz ) , 98.0 ( j 
 ch 171.5  hz ) , 84.2 , 83.6 , 82.6 , 81.0 , 78.8 , 78.7 , 78.5 , 78.4 , 75.7 , 75.6 , 75.6 , 75.5 , 75.0 , 74.9 , 74.8 , 74.6 , 74.6 , 74.6 , 74.1 , 73.5 , 73.2 , 73.0 , 72.8 , 72.7 , 72.4 , 72.0 , 69.1 , 67.3 , 66.7 , 63.7 , 50.5  ppm ; hrms ( esi ) : [ m+na ] 
 m / z calcd for c113h115o21n3na : 1872.7921 , found : 1872.7861 . ddq ( 10  mg , 44  mol ) was added to a vigorously stirred solution of 11 ( 34  mg , 18  mol ) in ch2cl2/tbuoh ( 4.4  ml , 10:1 ) at 20  c . the progress of the reaction was monitored by tlc ( toluene / etoac , 9:1 ) . the resulting mixture was extracted once with ch2cl2 ( 20  ml ) , the layers were separated , and the organic layer was washed with , 10  % aq . na2s2o3 solution ( 115  ml ) , dried over mgso4 , and concentrated in vacuo to a yellow oil . purification by flash column chromatography ( sio2 , toluenetoluene / etoac , 97:370:30 ) gave 12 ( 23  mg , 74  % ) as a colourless syrup : r 
 f=0.24 ( toluene / etoac , 9:1 ) ; [ ]d 
 + 10.2 ( c 1.0 , chcl3 ) ; h  nmr ( 600  mhz , cdcl3 ) : =7.516.92 ( m , 55  h ) , 5.22 ( d , j 1.6  hz , 1  h ) , 5.11 ( s , 2h ) , 5.03 ( d , j 10.6  hz , 1  h ) , 4.854.76 ( m , 4  h ) , 4.744.70 ( m , 2  h ) , 4.694.56 ( m , 8  h ) , 4.524.48 ( m , 2  h ) , 4.44 ( d , j 10.6  hz , 1  h ) , 4.39 ( d , j 11.0  hz , 1  h ) , 4.25 ( d , j 7.8  hz,1  h ) , 4.18 ( d , j 11.8  hz , 1  h ) , 4.154.11 ( m , 2  h ) , 4.06 ( dt , j 9.2 , 3.8  hz , 1  h ) , 4.044.00 ( m , 2  h ) , 3.993.88 ( m , 5  h ) , 3.83 ( ddd , j 10.1 , 6.0 , 3.6  hz , 1  h ) , 3.76 ( ddd , j 9.9 , 4.9 , 1.9  hz , 1  h ) , 3.743.68 ( m , 2  h ) , 3.683.59 ( m , 5  h ) , 3.53 ( ddd , j 10.7 , 7.0 , 3.6  hz , 1  h ) , 3.47 ( t , j 9.1  hz , 1  h ) , 3.443.40 ( m , 2  h ) , 3.363.28 ( m , 3  h ) , 3.24 ( ddd , j 13.2 , 6.1 , 3.7  hz , 1  h ) , 3.13  ppm ( t , j 11.1  hz , 1  h ) ; c  nmr ( 151  mhz , cdcl3 ) : =168.2 , 138.7 , 138.6 , 138.6 , 138.4 , 138.4 , 138.3 , 138.3 , 138.2 , 138.2 , 135.3 , 129.0 , 128.7 , 128.7 , 128.6 , 128.6 , 128.5 , 128.5 , 128.4 , 128.4 , 128.4 , 128.3 , 128.3 , 128.2 , 128.1 , 128.1 , 128.0 , 128.0 , 127.8 , 127.8 , 127.8 , 127.7 , 127.7 , 127.7 , 127.6 , 127.6 , 127.6 , 127.4 , 127.1 , 126.8 , 104.0 , 103.1 , 100.1 , 97.9 , 84.1 , 83.5 , 81.9 , a80.9 , 79.4 , 79.0 , 78.3 ( 2c ) , 78.0 , 77.9 , 75.8 , 75.7 , 75.2 , 74.9 , 74.8 , 74.8 , 74.5 , 74.4 , 73.5 , 73.5 , 73.1 , 72.6 , 72.5 , 72.0 , 69.1 , 68.9 , 68.5 , 67.3 , 66.8 , 64.3 , 50.5  ppm . hrms ( esi ) : [ m+na ] 
 m / z calcd for c102h107o21n3na : 1732.7205 , found : 1732.7264 . a mixture of 12 ( 22  mg , 13  mol ) , 13 
 9 ( 18  mg , 20  mol ) , and crushed molecular sieves ( 4   , 20  mg ) in dry et2o ( 3  ml ) was stirred at 20  c for 30  min . the reaction mixture was cooled to 0  c , freshly prepared dmtst ( 14  mg , 56  mol ) was added , and the reaction mixture was stirred at 0  c for 30  min . the progress of the reaction was carefully monitored by tlc ( toluene / etoac , 9:1 ) . the cooling bath was removed , and stirring was continued at 20  c for 1  h. et2o ( 6  ml ) was added and the reaction was quenched with et3n ( 40  l , 0.20  mmol ) at 0  c . the solids were removed by filtration through a pad of celite , and the filtrate was concentrated in vacuo . purification by flash column chromatography ( sio2 , toluenetoluene / etoac , 95:560:40 ) gave 14 ( 26  mg , 79  % ) as a colourless syrup : r 
 f=0.47 ( toluene / etoac , 9:1 ) ; [ ]d 
  4.2 ( c 1.0 , chcl3 ) ; h  nmr ( 600  mhz , cdcl3 ) : =7.95 ( s , 1  h ) , 7.827.74 ( m , 3  h ) , 7.64 ( dd , j 8.3 , 1.5  hz , 1  h ) , 7.48 6.91 ( m , 78  h ) , 5.64 ( d , j 1.4  hz , 1  h ) , 5.25 ( s , 1  h ) , 5.13 ( d , j 10.4  hz , 1  h ) , 5.08 ( m , 2  h ) , 4.99 ( m , 2  h ) , 4.87 ( d , j 10.9  hz , 1  h ) , 4.854.72 ( m , 5  h ) , 4.724.44 ( m , 18  h ) , 4.414.34 ( m , 4  h ) , 4.334.20 ( m , 6  h ) , 4.204.15 ( m , 2  h ) , 4.134.08 ( m , 1  h ) , 4.06 ( d , j 7.5  hz , 1  h ) , 4.033.81 ( m , 10  h ) , 3.783.71 ( m , 2  h ) , 3.713.60 ( m , 6  h ) , 3.593.53 ( m , 2  h ) , 3.49 ( t , j 8.5  hz , 1  h ) , 3.433.33 ( m , 3  h ) , 3.283.24 ( m , 2  h ) , 3.243.15 ( m , 2  h ) , 2.96 ( t , j 11.3  hz , 1  h ) , 1.63  ppm ( s , 3  h ) ; c  nmr ( 151  mhz , cdcl3 ) : =170.9 , 168.2 , 139.0 , 138.9 , 138.8 , 138.8 , 138.8 , 138.7 , 138.6 , 138.6 , 138.4 , 138.2 , 138.2 ( 3c ) , 138.1 , 136.7 , 135.5 , 133.5 , 133.1 , 129.2 , 128.8 , 128.8 , 128.5 , 128.5 , 128.5 , 128.4 , 128.4 , 128.3 , 128.3 , 128.2 , 128.2 , 128.1 , 127.9 , 127.9 , 127.8 , 127.8 , 127.8 , 127.8 , 127.7 , 127.7 , 127.7 , 127.6 , 127.6 , 127.5 , 127.4 , 127.4 , 127.3 , 127.3 , 127.1 , 127.1 , 126.7 , 125.9 , 125.8 , 104.3 ( j 
 ch 161  hz ) , 103.7 ( j 
 ch 162  hz ) , 102.9 ( j 
 ch 159.5  hz ) , 100.1 ( j 
 ch 171.6  hz ) , 99.6 ( j 
 ch 176.4  hz ) , 98.0 ( j 
 ch 169.8  hz ) , 84.1 , 84.0 , 83.5 , 82.6 , 81.1 , 81.0 , 79.5 , 79.2 , 79.2 , 79.1 , 79.0 , 78.4 , 78.0 , 75.7 , 75.6 , 75.5 , 75.5 , 75.4 , 75.0 , 75.0 , 74.9 , 74.7 , 74.7 , 74.6 , 74.5 , 74.4 , 74.3 , 73.7 , 73.6 , 73.3 , 73.1 , 73.0 , 72.5 , 72.5 , 72.0 , 71.7 , 70.6 , 69.1 , 68.2 , 67.2 , 66.9 , 64.3 , 64.1 , 64.0 , 50.5 , 20.8  ppm ; hrms ( esi ) : [ m+na ] 
 m / z calcd for c154h159o31n3na : 2569.0855 , found : 2569.0840 . 2aminoethyl dxylopyranosyl(12)6oacetyldmannopyranosyl(13) [ dglucopyranosyluronate(12 ) ] [ dxylopyranosyl(14)]dmannopyranosyl(13)d mannopyranoside  ( 15 ) . 10  % w pd / c ( 17  mg , 16.1  mmol ) was added to a solution of compound  14 ( 26  mg , 12.4  mmol ) in acoet / h2o / acoh ( 4:2:1 , 1.75  ml ) . the mixture was hydrogenolysed in a highpressure reactor ( berghof , eningen , germany ) at 20  c ( p=30  bar ) . after 48  h , sandwich filter ( 3  frits stacked on top of each other in the following order : 20  m , 10  m , 5  m ) , rinsed with h2o ( 32  ml ) and etoh ( 32  ml ) , and the filtrate was concentrated in vacuo . purification by reversedphase chromatography ( c18 , h2o / meoh , 9:18:27:36:42:80:10 ) , followed by freezedrying gave 15 ( 7.0  mg , 67  % ) as a colourless , amorphous solid ; [  ] 
 d+6.0 ( c 0.40 , h2o ) ; h  nmr ( 500  mhz , d2o ) : =5.25 ( s , 1  h ) , 5.17 ( s , 1  h ) , 4.90 ( s , 1  h ) , 4.47 ( d , j 7.8  hz , 1  h ) , 4.40 ( d , j 7.8  hz , 1  h ) , 4.374.33 ( m , 2  h ) , 4.31 ( d , j 7.8  hz , 1  h ) , 4.264.12 ( m , 5  h ) , 4.113.86 ( m , 10  h ) , 3.843.57 ( m , 10  h ) , 3.543.20 ( m , 9  h ) , 2.17  ppm ( s , 3  h ) ; c anomeric signals taken from heteronuclear single quantum coherence ( hsqc ) spectroscopy : 103.7 , 102.8 , 101.7 , 100.9 , 99.8 , 99.6  ppm ; hrms ( esi ) : [ m+na ] 
 m / z calcd for c38h63o31nna : 1052.3282 , found : 1052.3330 . a solution 16 ( 10.0  g , 29.6  mmol ) and dibutyltin oxide ( 9.96  g , 40.0  mmol ) in anhydrous toluene ( 320  ml ) was heated at reflux with continuous removal of water ( dean  stark trap ) . after 3  h , the mixture was concentrated to half volume , tetrabutylammonium iodide ( 14.8  g , 40.0  mmol ) and 2(bromomethyl)naphthalene ( 7.21  g , 32.6  mmol ) were added , and the reaction mixture was brought to reflux for another 3  h. to the reaction mixture , etoac ( 400  ml ) was added , and the organic layer was then washed sequentially with water ( 3200  ml ) , 10  % aq . kfsolution ( 3200  ml ) , and brine ( 2200  ml ) , dried over mgso4 , and concentrated in vacuo to a yellow oily residue . purification by flash column chromatography ( sio2 , pentanepentane / et2o , 50:5035:6525:7515:85 ) gave 17 ( 12.5  g , 88  % ) as a pale yellow syrup : r 
 f=0.33 ( toluene / etoac , 3:1 ) ; [ ]d 
 + 28.0 ( c 1.0 , chcl3 ) ; h  nmr ( 500  mhz , cdcl3 ) : =7.857.36 ( m , 12  h ) , 5.63 ( s , 1  h ) , 4.99 ( d , j 12.0  hz , 1  h ) , 4.91 ( d , j 1.5  hz,1  h ) , 4.90 ( d , j 12.0  hz , 1  h ) , 4.304.24 ( m , 1  h , h6a ) , 4.164.12 ( m , 2  h ) , 3.99 ( dd , j 3.0  hz , j 9.0  hz , 1  h ) , 3.893.83 ( m , 3  h ) , 3.60 ( ddd , j 3.7  hz , j 6.8  hz , j 10.6  hz , 1  h ) , 3.423.32 ( m , 2  h , ) , 2.74  ppm ( d , j 1.5  hz , 1  h ) ; c  nmr ( 125  mhz , cdcl3 ) : =137.7 , 135.5 , 133.4 , 133.2 , 129.1 , 128.4 , 128.4 , 128.1 , 127.8 , 126.8 , 126.3 , 126.3 , 126.1 , 125.9 , 101.9 , 100.4 , 78.8 , 75.6 , 73.2 , 69.9 , 69.0 , 66.9 , 63.9 , 50.5  ppm ; hrms ( esi ) : [ m+h ] 
 m / z calcd for c26h28n3o6 : 478.1978 , found : 478.1972 . a catalytic amount of tbdmsotf ( 335  l , 1.46  mmol ) was added to a solution of 3 
 16 ( 8.89  g , 14.66  mmol ) and 17 ( 7.00  g , 14.66  mmol ) in dry ch2cl2 ( 125  ml ) containing crushed molecular sieves ( aw300 , 180  mg ) kept at 78  c in an atmosphere of nitrogen . the temperature was then allowed to rise to 20  c overnight ( tlc , toluene / etoac , 6:1 ) . the reaction mixture was neutralised with et3n ( 1.23  ml , 8.79  mmol ) , the solids were removed by filtration , and the filtrate was concentrated in vacuo to a yellowish foam . purification by flash column chromatography ( sio2 , toluenetoluene / etoac , 98:296:494:692:890:1088:1286:14 ) gave 18 ( 11.70  g , 86  % ) as a colourless , amorphous solid : r 
 f=0.42 ( toluene / etoac , 9:1 ) ; [ ]d 
  48.8 ( c 1.0 , chcl3 ) ; h  nmr ( 500  mhz , cdcl3 ) : =8.238.22 ( m , 2  h ) , 8.088.07 ( m , 2  h ) , 7.977.95 ( m , 2  h ) , 7.87 ( m , 1  h ) , 7.817.78 ( m , 2  h ) , 7.717.69 ( m , 1  h ) , 7.587.36 ( m , 15  h ) , 7.277.24 ( m , 2  h ) , 5.61 ( t , j 4.2  hz , 1  h ) , 5.355.32 ( m , 1  h ) , 5.15 ( d , j 3.0  hz , 1  h ) , 5.11 ( s , 1  h ) , 5.10 ( d , j 2.4  hz , 1  h ) , 5.064.98 ( abq , 2  h ) , 4.95 ( dd , j 13.0  hz , j 1.6  hz , 1  h ) , 4.87 ( d , j 1.6  hz , 1  h ) , 4.30 ( dd , j 3.4  hz , j 1.6  hz 1  h ) , 4.104.05 ( m , 2  h ) , 3.99 ( t , j 9.5  hz , 1  h ) , 3.823.76 ( m , 2  h ) , 3.753.70 ( m , 1  h ) , 3.553.50 ( m , 1  h ) , 3.48 ( t , 1  h , j 10.5  hz ) , 3.372.27  ppm ( m , 2  h ) ; c  nmr ( 125  mhz , cdcl3 ) : =165.8 , 165.5 , 165.1 , 137.9 , 136.1 , 133.7 , 133.6 , 133.2 , 130.6 , 130.3 , 130.2 , 129.8 , 129.6 , 129.5 , 129.2 , 128.7 , 128.6 , 128.5 , 128.3 , 128.2 , 127.9 , 126.5 , 126.4 , 126.3 , 126.0 , 125.9 , 101.7 , 98.4 , 96.8 , 78.7 , 75.0 , 74.7 , 73.3 , 68.9 , 68.5 , 68.1 , 67.5 , 67.0 , 64.7 , 59.6 , 50.6  ppm ; hrms ( esi ) : [ m+na ] 
 m / z calcd for c52h47n3o13na : 944.3007 , found : 944.2960 . 
 2azidoethyl dxylopyranosyl(12)4,6obenzylidene3o(2naphthalenylmethyl)dmannopyranoside  ( 19 ) . a catalytic amount of sodium methoxide ( 68  mg , 1.27  mmol ) was added to a solution of 18 ( 11.70  g , 12.69  mmol ) in dry meoh ( 250  ml ) . the mixture was swirled at 20  c overnight ( tlc , ch2cl2/meoh , 9:1 ) . after complete conversion , dowex ( h ) acidic ion exchange resin was added for neutralisation , the resin was filtered off , washed with meoh ( 50  ml ) , and the filtrate was concentrated in vacuo . purification by flash column chromatography ( sio2 , dcmdcm / meoh , 99:198:297:396:495:5 ) gave 19 ( 11.70  g , 86  % ) as a colourless , amorphous solid : r 
 f=0.39 ( dcm / meoh , 9:1 ) ; [ ]d 
  1.8 ( c 1.0 , chcl3 ) ; h  nmr ( 500  mhz , cdcl3 ) : =7.827.78 ( m , 3  h ) , 7.757.73 ( m , 1  h ) , 7.527.44 ( m , 5  h ) , 7.407.36 ( m , 3  h ) , 5.66 ( s , 1  h ) , 5.05 ( d , j 11.7  hz , 1  h , ) , 4.88 ( d , j 11.7  hz , 1  h , ) , 4.85 ( d , j 1.5  hz , 1  h , ) , 4.53 ( d , j 7.0  hz , 1  h , ) , 4.274.35 ( m , 1  h ) , 4.214.17 ( m , 2  h ) , 4.08 ( dd , j 3.0  hz , j 9.0  hz , 1  h , ) , 4.054.02 ( m , 2  h ) , 3.893.81 ( m , 3  h ) , 3.643.58 ( m , 2  h ) , 3.493.46 ( m , 2  h ) , 3.37 ( m , 2  h ) , 3.26 ( dd , j 9.5  hz . j 11.5  hz , 1  h , ) , 3.14 ( s br , 1  h ) , 2.67  ppm ( s br , 1  h ) ; c  nmr ( 125  mhz , cdcl3 ) : =137.4 , 134.6 , 133.2 , 133.1 , 129.0 , 128.3 , 128.0 , 127.7 , 127.4 , 126.1 , 101.7 , 101.3 , 100.0 , 79.3 , 74.8 , 74.5 , 74.5 , 71.6 , 69.8 , 69.5 , 68.7 , 66.7 , 65.3 , 64.1 , 50.4  ppm ; hrms ( esi ) : [ m+na ] 
 m / z calcd for c31h35n3o10na : 632.2220 , found : 632.2195 . nah ( 3.81  g , 95.61  mmol , 60  % oil dispersion ) was washed with pentane ( 3100  ml ) prior to use . nah was added portionwise to a solution of 19 ( 12.96  g , 21.24  mmol ) in dry dmf ( 200  ml ) kept at 0  c under an atmosphere of nitrogen . after 15  min , benzyl bromide ( 10.09  ml , 84.96  mmol ) was added dropwise at 0  c under vigorous stirring . the temperature was then allowed to rise to 20  c over 3  h ( tlc , toluene / etoac , 6:1 ) . after complete consumption of the starting material , residual nah the resulting mixture was extracted once with etoac ( 600  ml ) , the layers were separated , and the organic layer was washed with brine ( 1400  ml ) , dried over mgso4 , and concentrated in vacuo . purification by flash column chromatography ( sio2 , toluenetoluene / etoac , 98:296:494:692:890:1088:12 ) gave 20 ( 16.87  g , 90  % ) as a colourless syrup : r 
 f=0.55 ( toluene / etoac , 6:1 ) ; [ ]d 
  8.0 ( c 1.0 , chcl3 ) ; h  nmr ( 500  mhz , cdcl3 ) : =7.86 ( m , 1  h ) , 7.817.79 ( m , 1  h ) , 7.767.74 ( m , 1  h ) , 7.687.66 ( m , 1  h ) , 7.527.48 ( m , 3  h),7.447.42 ( m , 2  h ) , 7.397.27 ( m , 18  h ) , 5.61 ( s , 1  h ) , 4.98 ( d , j 10.5  hz , 1  h ) , 4.95 ( d , j 1.6  hz , 1  h),4.914.85 ( m , 4  h ) , 4.734.69 ( m , 2  h ) , 4.61 ( d , j 11.6  hz , 1  h ) , 4.45 ( d , j 7.2  hz , 1  h ) , 4.28 ( m , 1  h ) , 4.214.17 ( m , 2  h ) , 4.033.99 ( m , 2  h ) , 3.863.78 ( m , 3  h ) , 3.66 ( ddd , j 5.2  hz , j 8.3  hz , j 9.5  hz , 1  h ) , 3.59 ( t , j 8.8  hz , 1  h ) , 3.563.49 ( m , 2  h ) , 3.35 ( ddd , j 3.5  hz , j 7.1  hz , j 13.3  hz , 1  h , ) , 3.303.23  ppm ( m , 2  h ) ; c  nmr ( 125  mhz , cdcl3 ) : =138.7 , 138.3 , 138.1 , 137.6 , 136.0 , 133.3 , 132.9 , 128.8 , 128.5 , 128.4 , 128.3 , 128.2 , 127.9 , 127.8 , 127.6 , 126.3 , 126.1 , 125.8 , 125.6 , 103.9 , 101.6 , 99.1 , 83.8 , 81.5 , 78.4 , 77.8 , 76.2 , 75.5 , 75.1 , 74.2 , 73.3 , 71.9 , 68.9 , 66.7 , 64.6 , 64.1 , 50.3  ppm ; hrms ( esi ) : [ m+na ] 
 m / z calcd for c52h53n3o10na : 902.3629 , found : 902.3613 . a 1  m solution of bh3 in thf ( 23.6  ml , 23.6  mmol ) was added to a solution of 20 ( 2.08  g , 2.36  mmol ) in dry ch3cn ( 40  ml ) kept at 0  c under an atmosphere of nitrogen . after 5  min , a 1  m solution of bu2botf ( 2.36  ml , 2.36  mmol ) was added dropwise at 0  c , and the reaction mixture was stirred for 90  min ( tlc , tolueneetoac , 6:1 ) . after complete consumption of the starting material , the reaction was quenched with et3n ( 10  ml ) , followed by dropwise addition of meoh ( 10  ml ) at 0  c . the mixture was concentrated in vacuo , and the residue was redissolved and coevaporated with meoh ( 350  ml ) . the syrupy residue was redissolved in meoh , the solids were removed by filtration through a short pad of celite , and the filtrate was concentrated in vacuo . purification by flash column chromatography ( sio2 , toluenetoluene / etoac , 97:394:691:988:1285:1582:1879:21 ) gave 21 ( 1.59  g , 76  % ) as a colourless syrup : r 
 f=0.16 ( toluene / etoac , 6:1 ) ; [ ]d 
 + 6.2 ( c 1.0 , chcl3 ) ; h  nmr ( 500  mhz , cdcl3 ) : =7.817.80 ( m , 2  h ) , 7.767.74 ( m , 1  h ) , 7.717.69 ( m , 1  h ) , 7.527.50 ( m , 1  h ) , 7.477.43 ( m , 2  h ) , 7.377.26 ( m , 20  h ) , 5.014.98 ( m , 2  h ) , 4.944.92 ( m , 2  h ) , 4.86 ( abq , j 12.0  hz , 2  h ) , 4.764.70 ( m , 3  h ) , 4.624.59 ( m , 2  h ) , 4.42 ( d , j 7.5  hz , 1  h ) , 4.16 ( m , 1  h ) , 4.003.97 ( m , 2  h ) , 3.90 ( t , j 9.5  hz , 1  h ) , 3.823.76 ( m , 2  h ) , 3.723.63 ( m , 3  h ) , 3.58 ( t , j 8.8  hz , 1  h ) , 3.543.49 ( m , 2  h ) , 3.363.32 ( ddd , 1  h ) , 3.293.21 ( m , 2  h ) , 1.62  ppm ( bs , 1  h ) ; c  nmr ( 125  mhz , cdcl3 ) : =138.7 , 138.6 , 138.4 , 138.1 , 135.6 , 133.3 , 133.1 , 128.5 , 128.38 , 128.37 , 128.3 , 127.99 , 127.97 , 127.94 , 127.92 , 127.89 , 127.87 , 127.8 , 127.7 , 127.6 , 127.5 , 127.1 , 126.5 , 125.9 , 125.8 , 103.8 , 98.2 , 83.9 , 81.2 , 78.1 , 77.5 , 75.5 , 75.2 , 74.8 ( 2c ) , 74.79 , 74.4 , 73.4 , 72.4 , 71.5 , 66.6 , 64.2 , 62.5 , 50.4  ppm ; hrms ( esi ) : [ m+na ] 
 m / z calcd for c52h55n3o10na : 904.3785 , found : 904.3763 . acetic anhydride ( 2.44  ml , 25.76  mmol ) was added to a solution of 21 ( 2.84  g , 1.47  mmol ) in dry pyridine ( 50  ml ) at 20  c , and the mixture was stirred for 3  h ( tlc , toluene / etoac , 9:1 ) . the reaction mixture was concentrated in vacuo , and then redissolved and coevaporated with toluene ( 3100  ml ) . purification by flash column chromatography ( sio2 , toluenetoluene / etoac , 97:394:691:988:1285:15 ) gave 22 ( 2.76  g , 93  % ) as a colourless syrup : r 
 f=0.25 ( toluene / etoac , 9:1 ) ; [ ]d 
 + 11.0 ( c 1.0 , chcl3 ) ; h  nmr ( 500  mhz , cdcl3 ) : =7.837.80 ( m , 2  h ) , 7.76 ( m , 1  h ) , 7.727.69 ( m , 1  h ) , 7.52 ( m , 1  h ) , 7.487.44 ( m , 2  h ) , 7.397.25 ( m , 20  h ) , 5.06 ( d , j 10.0  hz , 1  h ) , 4.99 ( d , j 11.5  hz , 1  h ) , 4.954.93 ( m , 2  h ) , 4.904.84 ( m , 2  h ) , 4.754.72 ( m , 2  h ) , 4.634.61 ( m , 2  h ) , 4.56 ( d , j 11.0  hz , 1  h ) , 4.40 ( d , j 7.0  hz , 1  h ) , 4.354.29 ( m , 2  h ) , 4.16 ( m , 1  h ) , 4.023.98 ( m , 2  h ) , 3.95 ( t , j 9.5  hz ) , 3.843.80 ( m , 2  h ) , 3.703.65 ( m , 1  h ) , 3.583.51 ( m , 3  h ) , 3.35 ( ddd , j 3.5  hz , j 7.1  hz , j 13.3  hz , 1  h ) , 3.28 ( ddd , j 3.0  hz , j 6.0  hz , j 9.8  hz , 1  h ) , 3.24 ( t , j 11.0  hz , 1  h ) , 1.75  ppm ( s , 3  h ) ; c  nmr ( 125  mhz , cdcl3 ) : =170.6 , 138.8 , 138.2 , 138.1 , 135.5 , 133.3 , 133.1 , 128.8125.8 , 104.1 , 98.2 , 83.9 , 81.4 , 78.2 , 77.4 , 75.6 , 75.2 , 75.1 , 75.0 , 73.8 , 73.4 , 71.5 , 70.2 , 66.6 , 64.2 , 63.3 , 50.4 , 20.5  ppm ; hrms ( esi ) : [ m+na ] 
 m / z calcd for c54h57n3o11na : 946.3891 , found : 946.3876 . nah ( 155  mg , 3.88  mmol , 60  % oil dispersion ) was washed with pentane ( 310  ml ) prior to use . nah was added portionwise to a solution of 21 ( 0.98  g , 1.11  mmol ) in dry dmf ( 40  ml ) kept at 0  c under an atmosphere of nitrogen . after 15  min , benzyl bromide ( 395  l , 3.33  mmol ) was added dropwise at 0  c under vigorous stirring . the temperature was then allowed to rise to 20  c over 2  h ( tlc , toluene / etoac , 6:1 ) . after complete consumption of the starting material , residual nah was quenched with meoh ( 2  ml ) , and then with h2o ( 80  ml ) . the resulting mixture was extracted once with etoac ( 160  ml ) , the layers were separated , and the organic layer was washed with brine ( 1100  ml ) , dried over mgso4 and concentrated in vacuo . purification by flash column chromatography ( sio2 , toluenetoluene / etoac , 98:296:494:692:890:10 ) gave 23 ( 1.03  g , 95  % ) as a colourless syrup : r 
 f=0.38 ( toluene / etoac , 9:1 ) ; [ ]d 
 + 7.8 ( c 1.0 , chcl3 ) ; h  nmr ( 500  mhz , cdcl3 ) : =7.827.80 ( m , 2  h , h ) , 7.757.73 ( m , 1  h ) , 7.707.68 ( m , 1  h ) , 7.527.50 ( m , 1  h ) , 7.477.15 ( m , 27  h ) , 5.06 ( d , j 10.5  hz , 1  h ) , 4.954.92 ( m , 3  h ) , 4.904.82 ( abq , 2  h ) , 4.754.71 ( m , 2  h ) , 4.61 ( d , j 10.5  hz , 1  h ) , 4.554.52 ( m , 2  h ) , 4.424.40 ( m , 3  h ) , 4.15 ( s , 1  h ) , 4.033.96 ( m , 3  h ) , 3.84 ( ddd , j 3.5  hz , j 5.8  hz , j 10.7  hz , 1  h ) , 3.813.77 ( m , 1  h ) , 3.753.64 ( m , 3  h ) , 3.573.49 ( m , 3  h ) , 3.35 ( ddd , j 3.5  hz , j 7.2  hz , j 13.3  hz , 1  h ) , 3.293.21  ppm ( m , 2  h ) ; c  nmr ( 125  mhz , cdcl3 ) : =138.9 , 138.6 , 138.6 , 138.3 , 138.2 , 135.7 , 133.3 , 133.1 , 128.9 , 128.5 , 128.3 , 128.2 , 128.2 , 128.0 , 127.95 , 127.92 , 127.87 , 127.64 , 127.60 , 127.54 , 127.51 , 127.47 , 127.4 , 127.1 , 126.5 , 125.9 , 125.7 , 104.1 , 98.2 , 84.0 , 81.2 , 78.3 , 77.4 , 75.5 , 75.2 ( 2c ) , 75.0 , 74.4 , 73.4 , 73.3 , 72.1 , 71.6 , 69.5 , 66.5 , 64.2 , 50.4  ppm ; hrms ( esi ) : [ m+na ] 
 m / z calcd for c59h61n3o10na , : 994.4255 , found : 994.4252 . ddq ( 393  mg , 1.73  mmol ) was added to a vigorously stirred solution of 23 ( 1.00  g , 1.08  mmol ) in ch2cl2/h2o ( 44  ml , 10:1 ) at 20  c . additional amounts of ddq ( 295  mg , 1.30  mmol ) were added after 20  min . more ddq ( 295  mg , 1.30  mmol ) was added after 40  min . the progress of the reaction was carefully monitored by tlc ( toluene / etoac , 6:1 ) . after 60  min , the reaction was quenched by adding 10  % aq . the resulting mixture was extracted once with ch2cl2 ( 200  ml ) , the layers were separated , and the organic layer was washed sequentially with sat . nahco3 solution ( 3150  ml ) , and brine ( 1150  ml ) , dried over mgso4 , and concentrated in vacuo . the residue was purified by flash column chromatography ( sio2 , toluenetoluene / etoac , 96:493:790:1087:1384:1680:20 ) . the first fraction to appear in the eluate contained recovered starting material ( 51  mg ) . solvent removal of the second and main fraction gave 24 ( 624  mg , 73  % ) as a colourless syrup : r 
 f=0.26 ( toluene / etoac , 6:1 ) ; [ ]d 
 + 42.0 ( c 1.0 , chcl3 ) ; h  nmr ( 500  mhz , cdcl3 ) : =7.367.24 ( m , 20  h ) , 4.99 ( d , j 11.0  hz , 1  h ) , 4.934.86 ( m , 3  h ) , 4.744.69 ( m , 3  h ) , 4.644.61 ( m , 2  h ) , 4.37 ( dd , j 2.0  hz , j 12.0  hz , 1  h ) , 4.34 ( d , j 8.0  hz , 1  h ) , 4.27 ( dd , j 4.5  hz , j 12.0  hz , 1  h ) , 4.03 ( td , j 3.4  hz , j 9.2  hz , 1  h ) , 3.973.91 ( m , 2  h ) , 3.843.78 ( m , 2  h ) , 3.663.50 ( m , 4  h ) , 3.423.36 ( m , 2  h ) , 3.343.28 ( m , 1  h ) , 3.23 ( dd , j 11.7  hz , j 10.3  hz , 1  h , ) , 3.17 ( d , j 9.5  hz , 1  h ) , 1.87  ppm ( s , 3  h ) ; c  nmr ( 125  mhz , cdcl3 ) : =170.7 , 138.6 , 138.3 , 138.0 , 137.9 , 128.6127.7 , 104.4 , 98.4 , 83.8 , 81.5 , 80.7 , 77.6 , 76.3 , 75.9 , 75.4 , 75.0 , 73.7 , 71.0 , 70.0 , 66.7 , 64.4 , 63.6 , 50.4 , 20.7  ppm ; hrms ( esi ) : [ m+na ] 
 m / z calcd for c43h49n3o11na : 806.3265 , found : 806.3230 ; anal . calcd for c43h49n3o11 : c 65.89 , h 6.30 , n 5.36 , found : c 65.70 , h 6.27 , n 5.31 . 
 2azidoethyl 2,3,4triobenzyldxylopyranosyl(12)4,6diobenzyl3o(2naphthalenylmethyl)dmannopyranosyl(13)[2,3,4triobenzyldxylopyranosyl(12)]6oacetyl4obenzyldmannopyranoside  ( 26 ) . a mixture of 24 ( 66  mg , 84.2  mol ) , 25 
 9 ( 119  mg , 125.6  mol ) , and crushed molecular sieves ( 4   , 20  mg ) in dry et2o ( 6  ml ) was stirred at 20  c for 30  min . the reaction mixture was cooled to 0  c , freshly prepared dmtst ( 64  mg , 248  mol ) was added , and the reaction mixture was stirred at 0  c for 30  min . the progress of the reaction was carefully monitored by tlc ( toluene / etoac , 9:1 ) . the cooling bath was removed , and stirring was continued at 20  c for 3  h. et2o ( 8  ml ) was added and the reaction was quenched with et3n ( 200  l ) at 0  c . the solids were removed by filtration through a pad of celite , and the filtrate was concentrated in vacuo . purification by flash column chromatography ( sio2 , toluene / etoac , 95:57:3 ) gave 26 ( 119  mg , 85  % ) as a colourless syrup : r 
 f=0.66 ( toluene / etoac , 9:1 ) ; [ ]d 
 + 3.5 ( c 1.0 , chcl3 ) ; h  nmr ( 500  mhz , cdcl3 ) : =7.80 ( m , 1  h ) , 7.767.74 ( m , 1  h ) , 7.707.67 ( m , 2  h ) , 7.507.48 ( m , 1  h ) , 7.427.14 ( m , 47  h ) , 5.19 ( s , 1  h ) , 5.06 ( d , j 11.0  hz , 1  h ) , 5.01 ( d , j 12.0  hz , 1  h ) , 4.97 ( d , j 10.5  hz , 1  h ) , 4.864.76 ( m , 7  h ) , 4.69 ( d , j 12.0  hz , 1  h ) , 4.64 ( d , j 10.0  hz , 1  h ) , 4.584.55 ( m , 3  h ) , 4.49 ( d , j 11.0  hz , 1  h ) , 4.45 ( d , j 12.0  hz , 1  h ) , 4.39 ( d , j 12.0  hz , 2  h ) , 4.344.20 ( m , 6  h ) , 4.124.08 ( m , 3  h ) , 3.983.93 ( m , 4  h ) , 3.843.68 ( m , 6  h ) , 3.583.53 ( m , 1  h ) , 3.503.36 ( m , 5  h ) , 3.333.25 ( m , 2  h ) , 3.223.17 ( m , 1  h ) , 3.06 ( t , j 10.8  hz , 1  h ) , 2.77 ( t , j 10.8  hz , 1  h ) , 1.84  ppm ( s , 3  h ) ; c  nmr ( 125  mhz , cdcl3 ) : =170.6 , 139.3 , 138.95 , 138.9 , 138.86 , 138.6 , 138.5 , 138.4 , 138.1 , 138.0 , 136.0 , 133.3 , 133.0 , 128.9 , 128.7 , 128.6 , 128.44 , 128.37 , 128.35 , 128.33 , 128.30 , 128.28 , 128.2 , 128.1 , 128.0 , 127.90 , 127.88 , 127.85 , 127.81 , 127.79 , 127.77 , 127.75 , 127.70 , 127.6 , 127.49 , 127.47 , 127.45 , 127.42 , 127.35 , 127.1 , 126.8 , 126.6 , 126.0 , 125.8 , 104.3 , 103.7 , 100.3 ( j 
 c1,h1 170  hz ) , 98.4 ( j 
 c1,h1 175  hz ) , 83.8 , 83.4 , 81.6 , 81.0 , 78.5 ( 2c ) , 77.7 , 77.4 , 77.1 , 75.8 , 75.6 , 75.3 , 75.12 , 75.09 , 74.9 , 74.7 , 74.4 , 73.4 , 73.2 , 72.5 ( 2c ) , 72.2 , 70.3 , 69.9 , 66.6 , 63.9 , 63.5 , 63.2 , 50.3 , 20.7  ppm ; hrms ( esi ) : [ m+na ] 
 m / z calcd for c100h105n3o20na : 1690.7189 , found : 1690.7153 ; anal . calcd for c100h105n3o20 : c 71.97 , h 6.34 , n 2.52 , found : c 71.99 , h 6.32 , n 2.54 . ddq ( 22  mg , 99  mol ) was added to a vigorously stirred mixture of compound  26 ( 104  mg , 62  mol ) in ch2cl2/h2o ( 11  ml , 10:1 ) at 20  c . additional amounts of ddq ( 17  mg , 75  mol ) were added after 20  min . more ddq ( 17  mg , 75  mol ) was added after 40  min . the progress of the reaction was carefully monitored by tlc ( toluene / etoac , 6:1 ) . after 60  min , the reaction was quenched by adding 10  % aq . the resulting mixture was extracted once with ch2cl2 ( 50  ml ) , the layers were separated , and the organic layer was washed sequentially with sat . nahco3 solution ( 330  ml ) , and brine ( 130  ml ) , dried over mgso4 , and concentrated in vacuo . the residue was purified by flash column chromatography ( sio2 , toluenetoluene / etoac , 96:493:790:10 87:1384:1681:1978:22 ) . the first fraction to appear in the eluate contained recovered starting material ( 13  mg ) . solvent removal of the second and main fraction gave 27 ( 76  mg , 80  % ) as a colourless foam : r 
 f=0.25 ( toluene / etoac , 6:1 ) ; [ ]d 
 + 13.6 ( c 1.0 , chcl3 ) ; h  nmr ( 500  mhz , cdcl3 ) : =7.387.13 ( m , 45  h ) , 5.19 ( s , 1  h ) , 4.994.94 ( m , 2  h ) , 4.94 ( d , j 11.0  hz , 1  h ) , 4.884.80 ( m , 6  h ) , 4.69 ( d , j 11.5  hz , 1  h ) , 4.664.57 ( m , 5  h ) , 4.51 ( s , 2  h ) , 4.364.24 ( m , 6  h ) , 4.134.06 ( m , 3  h ) , 3.99 ( dd , j 5.5  hz , j 12.0  hz , 1  h ) , 3.90 ( t , j 9.5  hz , 1  h ) , 3.853.83 ( m , 2  h ) , 3.803.68 ( m , 5  h ) , 3.60 ( t , j 9.3  hz , 1  h ) , 3.573.49 ( m , 2  h ) , 3.46 ( t , j 9.3  hz , 1  h ) , 3.443.39 ( m , 2  h ) , 3.36 ( t , j 9.0  hz , 1  h ) , 3.303.26 ( m , 2  h ) , 3.243.19 ( m , 1  h ) , 3.073.03 ( m , 2  h ) , 2.85 ( t , j 11.3  hz , 1  h ) , 1.84  ppm ( s , 3  h ) ; c  nmr ( 125  mhz , cdcl3 ) : =170.6 , 139.2 , 138.8 , 138.7 , 138.4 , 138.3 , 138.20 , 138.16 , 138.0 , 128.7 , 128.64 , 128.58 , 128.4 , 128.29 , 128.28 , 128.23 , 128.20 , 127.95 , 127.85 , 127.83 , 127.79 , 127.77 , 127.74 , 127.71 , 127.64 127.56 , 127.54 , 127.50 , 127.46 , 127.44 , 127.36 , 126.7 , 104.4 , 104.0 , 100.9 , 98.3 , 83.8 , 83.2 , 81.4 , 80.8 , 80.7 , 78.8 , 77.7 , 77.3 , 77.1 , 75.5 , 75.5 , 75.1 , 74.7 , 74.7 , 74.6 , 74.4 , 73.4 , 73.3 , 72.6 , 71.9 , 70.8 , 70.4 , 69.8 , 66.5 , 63.9 , 63.5 , 63.1 , 50.3 , 20.6  ppm ; hrms ( esi ) : [ m+na ] 
 m / z calcd for c89h97n3o20na : 1550.6563 , found : 1550.6541 . 2azidoethyl ( benzyl 2,3,4triobenzyldglucopyranosyluronate)(12)[2,3,4triobenzyldxylopyranosyl(14)]6obenzyl3o(2naphthalenylmethyl)dmannopyranosyl(13)[2,3,4triobenzyldxylopyranosyl(12)]4,6diobenzyldmannopyranosyl(13)[2,3,4triobenzyldxylopyranosyl(12)]6oacetyl4obenzyldmannopyranoside  ( 28 ) . a mixture of 27 ( 31  mg , 20.3  mol ) , 9 ( 41  mg , 29.4  mol ) , and crushed molecular sieves ( 4   , 20  mg ) in dry et2o ( 3  ml ) was stirred at 20  c for 30  min . the reaction mixture was cooled to 0  c , freshly prepared dmtst ( 22  mg , 88  mol ) was added , and the reaction mixture was stirred at 0  c for 30  min . the progress of the reaction was carefully monitored by tlc ( toluene / etoac , 9:1 ) . the cooling bath was removed , and stirring was continued at 20  c for 3  h. et2o ( 8  ml ) was added and the reaction was quenched with et3n ( 200  l ) at 0  c . the solids were removed by filtration through a pad of celite , and the filtrate was concentrated in vacuo . purification by flash column chromatography ( sio2 , toluene / etoac , 98:280:20 ) gave 28 ( 48  mg , 83  % ) as a colourless syrup : r 
 f=0.44 ( toluene / etoac , 9:1 ) ; [ ]d 
  18.9 ( c 1.0 , chcl3 ) ; h  nmr ( 500  mhz , cdcl3 ) : =7.827.78 ( m , 2  h ) , 7.71 ( d , j 8.1  hz , 1  h ) , 7.67 ( d , j 8.4  hz , 1  h ) , 7.51 ( d , j 8.4  hz , 1  h ) , 7.456.99 ( m , 87  h ) , 5.25 ( s , 1  h ) , 5.16 ( s , 1  h ) , 5.084.90 ( m , 5  h ) , 4.864.70 ( m , 8  h ) , 4.695.58 ( m , 7  h ) , 4.574.39 ( m , 9  h ) , 4.384.27 ( m , 7  h ) , 4.274.14 ( m , 8  h ) , 4.143.98 ( m , 8  h ) , 3.88 ( d , j 3.1  hz , 1  h ) , 3.84 ( d , j 7.7  hz , 1  h ) , 3.833.58 ( m , 9  h ) , 3.583.34 ( m , 11  h ) , 3.323.14 ( m , 4  h ) , 3.133.04 ( m , 2  h ) , 2.952.83 ( m , 2  h ) , 1.78  ppm ( s , 3  h ) ; c  nmr ( 125  mhz , cdcl3 ) : =170.8 , 168.1 , 139.0 , 139.0 , 138.9 , 138.9 , 138.8 , 138.7 , 138.7 , 138.7 , 138.6 , 138.6 , 138.6 , 138.5 , 138.4 , 138.3 , 138.2 , 138.1 , 136.3 , 135.2 , 133.3 , 133.0 , 129.2 , 128.8 , 128.8 , 128.8 , 128.7 , 128.7 , 128.6 , 128.6 , 128.5 , 128.5 , 128.4 , 128.4 , 128.4 , 128.3 , 128.3 , 128.3 , 128.2 , 128.2 , 128.1 , 1278.0 , 127.9 , 127.8 , 127.8 , 127.8 , 127.7 , 127.6 , 127.5 , 127.5 , 127.5 , 127.4 , 127.4 , 127.4 , 127.4 , 127.3 , 127.2 , 127.2 , 126.0 , 125.9 , 125.8 , 104.5 ( j 
 ch 160  hz ) , 103.8 ( j 
 ch 161.5  hz ) , 103.6 ( j 
 ch 163.5  hz ) , 102.8 ( j 
 ch 162.5  hz ) , 101.3 ( j 
 ch 172.5  hz ) , 99.4 ( j 
 ch 170  hz ) , 98.4 ( j 
 ch 171.5  hz ) , 84.4 , 84.0 , 83.4 , 83.4 , 82.6 , 81.7 , 81.5 , 80.9 , 79.5 , 79.1 , 78.8 , 78.8 , 78.6 , 78.5 , 78.2 , 76.3 ( 2c ) , 75.6 ( 2c ) , 75.5 ( 2c ) , 75.3 ( 3c ) , 75.0 ( 2c ) , 74.8 , 74.6 , 74.5 ( 2c ) , 74.3 , 73.7 ( 2c ) , 73.6 , 73.2 , 73.1 , 72.8 , 72.8 , 72.6 , 72.4 , 71.9 , 70.5 , 69.7 ( 2c ) , 67.2 , 66.6 , 63.7 , 63.6 , 63.5 , 63.4 , 50.4 , 20.7  ppm ; hrms ( esi ) : [ m+na ] 
 m / z calcd for c173h179n3o35na : 2881.2217 , found : 2881.2205 . ddq ( 7.2  mg , 32  mol ) was added to a vigorously stirred solution of 27 ( 45  mg , 15.7  mol ) in ch2cl2/tbuoh ( 1.6  ml , 10:1 ) at 20  c . the progress of the reaction was monitored by tlc ( toluene / etoac , 9:1 ) . the resulting mixture was extracted once with ch2cl2 ( 10  ml ) , the layers were separated , and the organic layer was washed with 10  % aq . na2s2o3 solution ( 6  ml ) , dried over mgso4 , and concentrated in vacuo to a yellow oil . purification by flash column chromatography ( sio2 , toluene / etoac , 94:670:30 ) gave 29 ( 42.8  mg , 68  % ) as a colourless syrup : r 
 f=0.40 ( toluene / etoac , 9:1 ) ; [ ]d 
  9.8 ( c 1.0 , chcl3 ) ; h  nmr ( 500  mhz , cdcl3 ) : =7.576.86 ( m , 85  h ) , 5.33 ( s , 1  h ) , 5.16 ( s , 1  h ) , 5.145.06 ( m , 2  h ) , 5.054.98 ( m , 3  h ) , 4.884.78 ( m , 6  h ) , 4.764.54 ( m , 13  h ) , 4.534.40 ( m , 6  h ) , 4.384.18 ( m , 9  h ) , 4.173.89 ( m , 15  h ) , 3.853.75 ( m , 2  h ) , 3.753.34 ( m , 17  h ) , 3.333.27 ( m , 2  h ) , 3.22 ( ddd , j 13.1 , 6.4 , 3.8  hz , 1  h ) , 3.173.04 ( m , 4  h ) , 2.93 ( dd , j 11.6 , 9.3  hz , 1  h ) , 1.79  ppm ( s , 3  h ) ; c  nmr ( 125  mhz , cdcl3 ) : =170.8 , 168.1 , 139.0 , 139.0 , 138.9 , 138.8 , 138.7 , 138.6 , 138.6 , 138.6 , 138.5 , 138.5 , 138.5 , 138.3 , 138.3 , 138.2 , 138.2 , 138.0 , 135.4 , 129.2 , 128.8 , 128.8 , 128.7 , 128.7 , 128.6 , 128.6 , 128.5 , 128.4 , 128.4 , 128.4 , 128.4 , 128.3 , 128.3 , 128.3 , 128.2 , 128.1 , 128.0 , 128.0 , 127.8 , 127.8 , 127.8 , 127.7 , 127.7 , 127.6 , 127.6 , 127.5 , 127.5 , 127.5 , 127.4 , 125.9 , 104.5 , 104.0 , 103.4 , 102.7 , 101.2 , 99.9 , 98.3 , 84.3 , 84.0 , 83.4 ( 2c ) , 82.0 , 81.7 , 81.3 , 80.5 , 79.8 , 79.0 , 78.9 , 78.6 , 78.4 , 78.2 , 78.1 , 77.9 , 77.9 , 77.4 , 75.6 , 75.6 , 75.5 , 75.4 ( 2c ) , 75.3 , 75.2 , 74.9 , 74.8 , 74.6 , 74.5 , 74.2 , 74.0 , 73.6 ( 2c ) , 73.4 , 73.2 , 73.2 , 73.0 , 72.0 , 71.9 , 70.5 , 69.7 , 68.9 , 68.2 , 67.2 , 66.7 , 64.2 , 63.9 , 63.7 , 63.3 , 50.4 , 20.8  ppm ; hrms ( esi ) : [ m+na ] 
 m / z calcd for c162h171n3o35na : 2741.1591 , found : 2741.1567 . as a service to our authors and readers , this journal provides supporting information supplied by the authors . such materials are peer reviewed and may be reorganized for online delivery , but are not copyedited or typeset . technical support issues arising from supporting information ( other than missing files ) should be addressed to the authors .
abstractas part of an ongoing project aimed at identifying protective capsular polysaccharide epitopes for the development of vaccine candidates against the fungal pathogen cryptococcus neoformans , the synthesis and glycosylation properties of a naphthalenylmethyl ( nap ) orthogonally protected trisaccharide thioglycoside , a common building block for construction of serotype b and c capsular polysaccharide structures , were investigated . 
 ethyl ( benzyl 2,3,4triobenzyldglucopyranosyl uronate)(12)[2,3,4triobenzyldxylopyranosyl(14)]6obenzyl3o(2naphthalenylmethyl)1thiodmannopyranoside was prepared and used both as a donor and an acceptor in glycosylation reactions to obtain spacer equipped hexa and heptasaccharide structures suitable either for continued elongation or for deprotection and printing onto a glycan array or conjugation to a carrier protein . 
 the glycosylation reactions proceeded with high yields and selectivity , proving the viability of the building block approach also for construction of 4oxylosylcontaining c.  neoformans cps structures .