Enantioselective N–H Functionalization of Indoles with α,β‐Unsaturated γ‐Lactams Catalyzed by Chiral Brønsted Acids

Nitrogen revives: Cyclic N-acyliminium ions were generated from α,β-unsaturated γ-lactams (1) and underwent intermolecular addition by indole nucleophiles (2) under the catalysis of a chiral Brønsted acid (3). A variety of N-functionalized indole derivatives containing a pyrrolidinone moiety (4) were assembled with high enantioselectivity. Bn=benzyl.