C-3 β-lactam carbocation equivalents: versatile synthons for C-3 substituted β-lactams

An efficient and operationally simple strategy for the synthesis of differently C-3 monosubstituted (9) and disubstituted (10) monocyclic beta-lactams is described. This involves reaction of beta-lactam carbocation equivalents (8) with active aromatic, aliphatic and heterocyclic substrates in the presence of a Lewis acid.