Highly Efficient Ethenolysis and Propenolysis of Methyl Oleate Catalyzed by Abnormal N-Heterocyclic Carbene Ruthenium Complexes in Combination with a Phosphine-Copper Cocatalyst

Abstract

Fluorinated imidazo[1,5-a]pyridine abnormal carbene ruthenium complexes (F-aImPy-Ru) with a tricyclohexylphosphine copper chloride (Cy3P-CuCl) cocatalyst were developed for the ethenolysis/propenolysis of methyl oleate. These catalysts showed remarkable catalytic efficiencies (turnover numbers of 100,000 for ethenolysis and 200,000 for propenolysis) and excellent alpha-olefin selectivity (up to 99%). A computational study indicated that the energy barrier of the beta-hydride elimination pathway in the presence of a phosphine-copper cocatalyst is higher than that in the absence of the cocatalyst, which might contribute to the improved longevity of the ruthenium catalyst in the reaction.