Iron‐Catalyzed Cyclotrimerization of Terminal Alkynes by Dual Catalyst Activation in the Absence of Reductants

Abstract

Abstract Catalyzing C−C bond‐forming reactions with earth‐abundant metals under mild conditions is at the heart of sustainable synthesis. The cyclotrimerization of alkynes is a valuable atom‐efficient reaction in organic synthesis that is enabled by several metal catalysts, including iron. This study reports an effective iron‐catalyzed cyclotrimerization for the regioselective synthesis of 1,2,4‐substituted arenes (1 mol % catalyst, toluene, 20 °C, 5 min). A dual activation mechanism (substrate deprotonation, reductive elimination) renders the simple Fe II precatalyst highly active in the absence of any reductant.