An Efficient and Enantioselective Synthesis of d-Biotin

Abstract

An efficient and enantioselective synthesis of d-biotin 1 starting from cis 1,3-dibenzyl-2-imidazo-lidone-4,5-dicarboxylic acid (6) is described. The key steps are the enantioselective reduction of meso-1,2-dicarboxylic thioanhydride 8 to prepare the (3aS,6aR)-thiolactone 9 and the introduction of the C6 side chain at C-2 in 9 via a modified Grignard reaction. This novel synthesis proceeded in six steps to afford 1 with 21% overall yield.