A Novel, Industrially-feasible Synthetic Route to (+)-Biotin from L-Cysteine

A novel, industrially viable synthetic route to (+)-biotin has been developed starting from L-cysteine via the known key thiolactone intermediate. The route takes advantage of the in-built stereochemistry of the cysteine starting material and the best features of the two current industrialized processes. The key transformations are the conversion of L-cysteine into a hydantoin avoiding racemization followed by catalytic cyanation and thiolactonization to form the required thiolactone intermediate. This known intermediate can be readily further transformed into (+)-biotin.