Asymmetric Benzoin Reactions with N-Heterocyclic Carbene Catalysts

The discovery of stable carbenes in the last decade of the 20th century has brought about extensive research on the chemistry of N-heterocyclic carbenes. Recently the powerful catalytic activity of N-heterocyclic carbenes has been demonstrated by new organocatalytic transformations. This review focuses on the asymmetric benzoin reactions catalyzed by N-heterocyclic carbenes. Chiral nucleophilic carbenes catalyze the benzoin condensation in good yields and exellent enantioselectivities.