A highly stereocontrolled total synthesis of (+)-biotin from l-cysteine

(+)-Biotin was synthesized in 11 steps and in 25% overall yield from readily accessible l-cysteine through a Lewis base-catalyzed highly diastereoselective cyanosilylation of (2R,4R)-N-Boc-2-phenylthiazolidine-4-carbaldehyde 2 and a ring closure of a cis-allylic carbonate 5b utilizing a palladium-catalyzed intramolecular allylic amination.