Abstract

N-Heterocyclic carbenes (NHCs) as versatile nucleophilic organocatalysts have been extensively studied and also widely applied in organic reactions. The types of organic reactions catalyzed by N-heterocyclic carbenes are broad including benzoin condensation, Stetter reaction, a³-to-d³ umpolung, ring-opening reaction, transesterification, and ring expansion polymerization. This review reports recent developments in the synthesis of heterocycles (such as lactams, lactones, chromones, and benzofuranones) catalyzed by N-heterocyclic carbenes.

Keywords: Benzofuranone, chromone, heterocycles, lactam, lactone, N-heterocyclic carbene, organocatalyst.

Graphical Abstract