Mechanism And Selectivity Of Copper-Catalyzed Borocyanation Of 1-Aryl-1,3-Butadienes: A Computational Study

Density functional theory calculations have been performed to investigate the copper-catalyzed borocyanation of 1-aryl-1,3-butadienes. The computations show that the regio- and enantioselectivity is determined by the borocupration step. The pi-electron withdrawing aryl group at the C-1 atom makes the C-4 atom more electrophilic than the other carbon atoms, which together with the steric repulsion around the forming C-B bond, results in the experimentally observed exclusive 4,3-regioselectivity. The origins of the enantioselectivity were attributed to the steric effect and pi-pi stacking interaction between the butadiene moiety and the ligand. (C) 2020 Chinese Chemical Society and Institute of Materia Medica, Chinese Academy of Medical Sciences. Published by Elsevier B.V. All rights reserved.