Dithiocarbamate as a Carbonyl Alternative in Pd-Catalyzed Carbonylative Homocoupling of Organoboronic Acids

Abstract

We have developed a novel protocol for carbonylative homocoupling of arylboronic acids using dithiocarbamate esters as the carbonyl alternative. A series of arylboronic acids underwent smooth reaction with dithiocarbamate ester (Me₂NCS₂Me) in the presence of Pd(PPh₃)₂Cl₂ catalyst, Cu(OAc)₂·H₂O additive, and Na₂CO₃ in DCE solvent, producing the biaryl ketones efficiently. The mechanism has been studied with the help of several control experiments that reveal the probability of thioamide intermediacy. Chemoselective homocoupling allows the postsynthetic modification of the product.