To obtain 5,5-disubstituted sultones 159, dialkyl-or cycloalkylidene cyanohydrins 160 were used. The common sulfonylation with MsCl the presence of pyridine or Et3N resulted the formation of sulfonates 161a-m in 50-87% yield (Table ). Further intramolecular cyclization in the presence of NaH in THF or MeCN resulted in the formation of the β-enamino-γ-sultone fragment 159. It is shown that this method is suitable both for the synthesis of C-5 monoalkyl-and for obtaining 5,5-bisalkyl-substituted derivatives 159. Monoalkyl-substituted cyanohydrins can also be used in sulfonylation reactions with homologous alkyl sulfonyl chlorides followed by carbanion cyclization. The present method was studied with homologous sulfonylating agents, e.g. ethane sulfonyl chloride, and benzyl sulfonyl chloride (Scheme 26). The cyclization reaction of sulfonates 162 into enaminosultones 163 proceeded smoothly by the use of DBU or NaH. Additionally, for certain substrates containing a benzyl substituent, Cs2CO3 in MeCN was found to be the preferred choice, whereas the use of DBU led to E2-elimination with the formation of substituted acrylonitrile. Scheme 26. Synthesis of 3-substituted enaminosultones 1.108 with acetone cyanohydrin The scope of spirocyclic derivatives includes sultones, which were synthesized by sulfonylation of N-protected piperidine cyanohydrins 164 with methane-, ethane-, and benzyl sulfonyl chlorides upon the common conditions in the presence of Et3N and CH2Cl2 to give sulfonates 165 in good yields ranging from 65% to 95%. Subsequently, these intermediates were subjected to CSIC reaction for the synthesis of spirocyclic analogs 166 using NaH or DBU as bases to provide enaminosultones in 69-91% yield (Scheme 27). 61 This synthetic strategy can be extended to bridged bicyclic cyanohydrins, enabling the synthesis of polycyclic alkylsultones. Specifically, 3-spiroquinuclidine 167 was obtained in 85% yield from the corresponding cyanohydrin 168 through mesylation followed by treatment with ammonia (Scheme 28). 104 Scheme 28. Synthesis of 3,3-substituted spiroquinuclidine 1.112 Furthermore, the transformation of adamantanone 169 into the corresponding cyanohydrin 170 was reported. Without isolation of 170 from the reaction mixture, it was subjected to mesylation-cyclization reactions, resulting in the formation of sulfonate 171 with a yield of 53% (Scheme 29). Subsequent cyclization under the action of any of the above-mentioned bases (DBU, NaH, Cs2CO3) with comparable efficiency led to the synthesis of spirocyclic 5,5adamantyl sultone 172 in 85% yield. 105