In accord with this plan, our retrosynthesis is depicted in Scheme 1. After a late stage hemiacetalization of heteroatom-rich linear precursor C, deoxygenation and azide reduction would furnish target A. C would be built systematically from epoxide F. We envisioned our laboratory's sulfamate-tethered aza-Wacker cyclization would serve as a key step during the transformation of epoxide F into aldehyde C. The successful execution of this strategy would increase the prominence of both classical and tethered aza-Wacker chemistry for the stereoselective assembly of complex targets. Our forward synthesis (Scheme 2) commenced with morpholine amide 1, itself prepared in two steps from commercial Derythrono-1,4-lactone in a procedure developed and disclosed by our laboratory. Morpholine amide 1 was converted into diol 2 by heating with NaBH4 in EtOH. Treatment of diol 2 with benzoyl chloride in ice-cold CH2Cl2 allowed for selective esterification of the primary alcohol. The secondary alcohol of benzoate 3 was tosylated using a standard mixture of NEt3, TsCl, and catalytic DMAP. Treatment of 4 with mixture of K2CO3 in MeOH allowed for the hydrolysis of the benzoate ester; the resulting alkoxide anion displaced the tosylate in an intramolecular SN2 reaction to form epoxide 5. CuI mediated the regioselective opening of epoxide 5 by cis-1-propenyl-magnesium bromide. For this transformation, we have found that it is critical to freshly prepare cis-1-propenylmagnesium bromide; for reasons unknown, using commercial solutions of 1-propenylmagnesium bromide did not allow for clean reactivity. Sulfamoylation of alcohol 6 proceeded smoothly with Johnson and Magolan's protocol. As a first step to evaluating the sulfamate-tethered aza-Wacker cyclization with 7, we tested our standard protocol of Pd(OAc)2/Cu(OAc)2 in hot CH3CN and a ~1 atm O2 atmosphere. We were pleased that this delivered desired oxathiazinane 8 in a 36% yield, an excellent starting point for further optimization (Scheme 3, Entry 1). Switching to Pd2(dba)3 at a higher loading increased the yield to 50% (Scheme 3, Entry 2). Using PdCl2(nbd) and Pd(CH3CN)2Cl2 in place of Pd2(dba)3 did not help the reaction (Scheme 3, Entries 3-5). We have previously observed a dramatic improvement in sulfamate-tethered aza-Wacker cyclizations when mono-protected amino acid ligands and 4Å molecular sieves are used. We hypothesize, in accord with the Yu laboratory's observations, that mono-protected amino acids (MPAA) ligands help promote the Pd (II) -Pd (0) catalytic cycles operative during aza-Wacker transformations. Indeed, in line with our predictions, the yield of oxathiazinane 8 increased to 63% upon the addition of MPAA ligand Fmoc-Gly-OH and 4Å molecular sieves (Scheme 3, Entry 6). Despite the presence of molecular sieves, it was critical to use anhydrous DMSO for the best reaction yield. X-ray structural analysis of 8 (CCDC: 2289376) allowed us to unambiguously confirm its identity and absolute stereochemistry.