An efficient method for the synthesis of 3-mercapto-1-(1,3-thiazolin-2-yl)azetidine useful for the pendant moiety of oral carbapenem, L-084

An efficient method for the synthesis of 3-mercapto-l-(l,3-thiazolin-2-yl)azetidine (1) is described. This thiol synthesis was achieved in 3 steps from readily available 3-methanesulfonyloxyazetidine via key intermediates, Bunte salts (3 and 5). The final step was enabled to proceed under mild conditions using the benzylthiol-mediated cleavage of the S-S bond in the Bunte salt (3).