Asymmetric synthesis of monocyclic β-lactams from l-cysteine using photochemistry

An asymmetric method to synthesize cis-configured β-lactams using photochemistry has been developed. Aerobic photo-oxidation of l-cysteine-derived thiazolidine hydroxamate esters afforded C-3 hydroxylated products which when cyclized and deprotected gave the corresponding N-protio monocyclic β-lactams.