Mechanistic insights and computational design of Cu/M bimetallic synergistic catalysts for Suzuki-Miyaura coupling of arylboronic esters with alkyl halides

Carbonylative Suzuki-Miyura coupling reaction is one of the most efficient methods to synthetize ketones. In this work, the reaction mechanism of arylboronic esters with alkyl halides catalyzed by Cu/Mn synergistic catalysts has been studied by DFT calculation. The calculated results show that the whole reaction contains two cycles, one is the Cu-catalyzed transformation of Ar-Bneop to RO-Bneop, and the other is Mn-catalyzed Heck–Breslow cycle for alkyl halide carbonylation. At the last step, the final product aryl ketone is produced through the C-C cross-coupling between the two intermediates, which form from the above separate two cycles. For the title reaction, the [Mn(CO)5]− catalyzed the Heck–Breslow cycle belongs to SN2 mechanism, and Mn2(CO)10 catalyzed cycle is SET mechanism. In addition to [Mn(CO)5]−, the metal carbonyl anions with moderate even low nucleophilicity are suitable to co-catalyze the carbonylative Suzuki-Miyaura coupling with the Cu-carbene catalyst. Our calculation results are consistent with and provide explanations the experimental observations, as well as shed lights on further advancement of new bimetallic catalysts.