FeCl₂-Catalyzed Decarboxylative Radical Alkylation/Cyclization of Cinnamamides: Access to Dihydroquinolinone and Pyrrolo[1,2-<i>a</i>]indole Analogues

Abstract

A simple and unified method for the synthesis of alkylated dihydroquinolinone and pyrrolo[1,2- a]indole derivatives in moderate to high yields (up to 91%) with excellent diastereoselectivity (>20:1 dr) was developed. The inexpensive FeCl₂·4H₂O works as catalyst, and easily prepared peresters (or peroxides) from aliphatic acids act as alkylating reagents and single electron oxidants. This environmentally friendly reaction proceeds via an FeCl₂-catalyzed alkyl radical cascade addition/cyclization fashion.