Abstract
The reaction of racemic a-keto beta-lactams 5a5c with the commercially available chiral compound trans-4-hydroxy-L-proline (6) in the presence of a catalytic amount of Bi(NO3)3 center dot 5 H2O in EtOH gave a diastereoisomer mixture of beta-lactams with a pyrrole ring at C(3) (7 to 12). This is the first enantioselective synthesis of optically active beta-lactams (=azetidin-2-ones) that possess a pyrrolyl residue at C(3), in a single step.