Oxazolidinone aldehyde 10 reacts with L-cysteine methyl ester to produce N-hydroxymethyl bicyclic γ-lactam 11 in a double cyclisation reaction. With D-cysteine methyl ester, an epimeric mixture of N-hydroxymethyl bicyclic γ-lactams 12 is obtained. Bicyclic γ-lactams 3, 4 and 13 are easily prepared from 11 and 12.
