A continuum of progress: Applications of N-hetereocyclic carbene catalysis in total synthesis

N-Heterocyclic carbene (NHC) catalyzed transformations have emerged as powerful tactics for the construction of complex molecules. Since Stetter's report in 1975 of the total synthesis of cis-jasmon and dihydrojasmon by using carbene catalysis, the use of NHCs in total synthesis has grown rapidly, particularly over the last decade. This renaissance is undoubtedly due to the recent developments in NHC-catalyzed reactions, including new benzoin, Stetter, homoenolate, and aroylation processes. These transformations employ typical as well as Umpolung types of bond disconnections and have served as the key step in several new total syntheses. This Minireview highlights these reports and captures the excitement and emerging synthetic utility of carbene catalysis in total synthesis. A modern touch: The field of N-heterocyclic carbene catalysis has grown rapidly over the last decade. This expansion has generated a wide variety of new asymmetric transformations including benzoin and Stetter reactions as well as the more modern homoenolate equivalent and aroylation coupling reactions, which have been used successfully in total syntheses (see scheme).