Room-temperature and transition-metal-free intramolecular α-arylation of ketones: A mild access to tetracyclic indoles and 7-azaindoles

Abstract

A novel approach for the synthesis of tetracyclic indoles and 7-azaindoles is reported. The strategy involves four steps, with a fast rt intramolecular α-arylation of ketones as key step. The reaction was inspected synthetically to achieve the synthesis of 11 novel tetracyclic structures with moderate to very good yields (39-85%). Theoretical combined with experimental studies led us to propose a probable polar mechanism (concerted S N Ar).