Synthetic studies on d-biotin, part 6: an expeditious and enantiocontrolled approach to the total synthesis of d-biotin via a polymer-supported chiral oxazaborolidine- …
Abstract An efficient and highly enantioselective synthesis of d-biotin from the known cis-1, 3- dibenzyl-2-imidazolidone-4, 5-dicarboxylic acid (5) was accomplished in 48% overall yield. The key reactions in the sequence involve the catalytic enantioselective reduction of meso- cyclic imide 6 using polymer-supported chiral oxazoborolidine, derived from (S)-α, α- diphenylprolinol and polymer-bound sulfonyl chloride, and the installation of the C 5 side ...
