Total synthesis of Vitamin D3 and its analogs via vinyl sulfone chemistry.

摘要

A general method has been developed for the synthesis of enantiopure six and seven membered A-ring of Vitamin D3 using dimethylsulfonium methylide. A new coupling strategy has been developed for the total synthesis of Vitamin D3 and 19-nor-Vitamin D3 analogs which involves the reaction of A-ring sulfonyl anion with CD-ring allyl chloride and subsequent desulfonylation and concomitant silyl ether deprotection using TBAF. Enantioselective CD-ring synthesis is also achieved from achiral dienyl sulfone.