Development of chiral bicyclic triazolium salt organic catalysts:: The importance of the N-aryl substituent

The development of a family of chiral bicyclic triazolium salts is described. Treatment of these salts with base provides a nucleophilic carbene which may be used as an organic catalyst for asymmetric acyl anion chemistry including the benzoin and Stetter reactions, and some recently developed redox chemistry. Throughout the development of these reactions, the nature of the N-aryl substituent on the triazole ring has proven to have a profound effect on both reactivity and selectivity. These observations have also paralleled those made by others using our family of catalysts.