Synthesis of (+)-biotin: Efficient resolution of key intermediates

Article abstract of DOI:10.1016/S0040-4020(01)90062-6

Enantiomerically pure 4-chlorothieno[3,4-d]imidazol-2-one (+)-2 and thieno[3,4-d]imidazol-2,4-dione (+)-5, key intermediates in independent routes to (+)-biotin (6), have been prepared by resolution via the corresponding diastereomeric ethers (3d-g and 3'd-g). Efficient procedures to recycle the undesired diastereomers and recover the chiral auxiliary have been developed.