Intermolecular Stetter Reaction by NHC Catalysis

Significance

The authors report the new N-benzyl-substituted triazolium salt 1 as N-heterocyclic carbene (NHC) precursor and its use in intermolecular, enantioselective Stetter reactions of aldehydes and chalcones. A kinetic study of the reaction showed rapid consumption of the aldehyde leading to benzoin condensation (BC) product 2. However, the Stetter reaction took place with high yields and good enantioselectivities (high ratios after recrystallization), because the initial BC (I) is reversible.