Kinetic and structure-activity studies of the triazolium Ion-catalyzed intramolecular stetter reaction

Abstract

Mechanistic studies of the triazolium ion‐catalyzed intramolecular Stetter reaction using initial rates analysis in NEt3/NEt3. HCl buffered methanol showed the reaction to be first order in catalyst and zero order in aldehyde over a broad range of aldehyde concentrations. The observed reaction rate is higher for catalysts bearing N‐aryl substituents with electron‐withdrawing groups. A concurrent, NHC‐independent substrate isomerization was also observed and found to demonstrate a first order dependence on aldehyde concentration. The reported data are consistent with deprotonation to form the Breslow intermediate being turnover‐limiting in this process.