New insight into Cu-catalyzed borocarbonylative coupling reactions of alkenes with alkyl halides

Density functional theory (DFT) calculations were performed to better understand the mechanism of copper-catalyzed four-component borocarbonylative coupling of alkenes with alkyl halides by using bis(pinacolato)diboron as the boron reagent under CO atmosphere as reported in the recent literature. An unexpected reaction mechanism was shown to be viable, which occurs via a CuI-only involved, two-ligand relay-enabled, and no radical-participated copper catalysis with a SN2-type C-C coupling fashion. The theoretical results rationalized the experimentally observed regio- and chemoselectivities, and substituent effect of alkenes as well as the fact the reaction is totally inhibited by radical trapping reagents.