Radical Anions from Urea-type Carbonyls: Radical Cyclizations and Cyclization Cascades

Abstract

Radical anions generated from urea carbonyls by reductive electron transfer are exploited in carbon–carbon bond formation. New radical cyclizations of urea radical anions deliver complex nitrogen heterocycles and, depending upon the proton source used in the reactions, a chemoselective switch between reaction pathways can deliver two heterobicyclic scaffolds. A computational study has been used to investigate the selectivity of the urea radical processes. Furthermore, radical cyclization cascades involving urea radical anions deliver unusual spirocyclic aminal architectures.