Enantioselective intramolecular α-amidoalkylation reaction in the synthesis of pyrrolo[2,1-a]isoquinolines

BINOL-derived chiral Brønsted acids are capable of carrying out the intramolecular α-amidoalkylation of a tertiary N-acyliminium ions when a methoxylated benzene ring is used as internal π nucleophile. The reaction can be applied to the synthesis of pyrrolo[2,1-a]isoquinolines and use of the sterically congested acid 3e is determinant to obtain good levels of enantioselection.