DFT calculations reveal the origin of controllable synthesis of β-boronyl carbonyl compounds from Cu/Pd-cocatalyzed four-component borocarbonylation of vinylarenes

Abstract

This paper shows a DFT-based comparative mechanistic study on the Cu/Pd-cocatalyzed four-component borocarbonylative reactions among vinylarenes, aryl halides/triflates, bis(pinacolato)diboron (B₂pin₂), and CO to rationalize the experimental observation that aryl iodides deliver β-boryl ketones while aryl triflates afford β-boryl vinyl esters. The divergence in reactivity caused by different starting materials (aryl halides/triflates) is attributed to the different formation rates of intermediates in the copper and palladium catalytic cycles. The strength of C(sp²)–X (X = I, OTf) bond and the relative stabilities of reactive aryl and acyl palladium intermediates are mainly responsible for the different formation rates. The theoretical results would provide assistance in further designing the synthesis of β-boryl carbonyl compounds using synergistic Cu–Pd catalysis.