N,N,N′,N′-Tetramethylethylenediamine-Copper Salt-catalysed Coupling of Aryl Grignard Reagents with Alkyl and Aralkyl Halides

Abstract

Abstract In the presence of N,N,N′,N′-tetramethylethylenediamine (TMEDA) and a small amount of copper salt, phenyl- and p-tolylmagnesium bromides react with alkyl or benzyl halide to give cross-coupling products in benzene or in a benzene-diethyl ether solvent. Among the alkyl iodides, normal iodides are most reactive, while secondary iodides do not react under our conditions. As copper salts, CuCl, CuCl2, CuCl2(TMEDA), and CuBr are all efficient for catalysis. This newly-developed catalytic system of TMEDA-copper salt is thought to be useful for the syntheses of polyalkyl-substituted aromatic hydrocarbons. As the reaction mechanism, the intermediate formation of TMEDA-coordinated organocopper(I) species and the nucleophilic displacement is proposed.