Cross Alkyl-Aryl Versus Homo Aryl-Aryl Coupling in Pdcatalyzed Coupling of Alkyl-Gold(I) and Aryl-X (X = Halide)

Abstract

Experiments on palladium catalyzed cross-coupling of [AuMe(PPh3)] with aryl iodides show that Ar–Ar homocoupling products are the main product or an abundant byproduct of the reaction. The percentage of cross-coupling product is higher for aryls with larger p Hammet parameter. The scrambling of organic groups via bimetallic intermediates explains the formation of these products. This scrambling can be observed and the activation energies partially quantified in some cases using as aryl C6Cl2F3, which is relatively reluctant to coupling.