A phosphine-free heterogeneous coupling of acyl chlorides with terminal alkynes catalyzed by an MCM-41-immobilized palladium complex

Abstract

The phosphine-free heterogeneous coupling of acyl chlorides with terminal alkynes was achieved in triethylamine at 50 °C in the presence of a 0.2 mol% 3-(2-aminoethylamino)propyl-functionalized MCM-41-immobilized palladium complex [MCM-41-2N-Pd(OAc)₂], yielding a variety of ynones in good to excellent yields. This novel heterogeneous palladium catalyst can be conveniently prepared from commercially available and cheap reagents and recycled by a simple filtration of the reaction solution, and used for at least 10 consecutive trials without any decrease in activity. Our system not only avoids the use of phosphine ligands, but also solves the basic problem of palladium catalyst recovery and reuse.