Copper-catalyzed and biphosphine ligand controlled 3,4-boracarboxylation of 1,3-dienes with carbon dioxide

A strategy for copper-catalyzed and biphosphine ligand controlled boracarboxylation of 1,3dienes and CO2 with 3,4-selectivity was developed. The CuCl coupled with DPPF (1,1' bis(diphenylphosphino)ferrocene) was assigned to be the best catalyst, with 84 % yield and exclusive 3,4-selectivity. The ligand effect on both catalytic activity and regioselectivity of boracarboxylation was disclosed, which is rarely reported in any copper catalyzed boracarboxylation. The borocupration process is revealed to be a vital step for the biphosphine participated boracarboxylation of 1,3-dienes with CO2 . The minimal substrate distortion occurring in 3,4-borocupration favors the 3,4-regioselectivity of boracarboxylation. The "pocket" confinement and suitable /3n (92 degrees-106 degrees) of bisphosphine ligands are demonstrated to be in favour of the interaction between LCu-Bpin complex (the catalytic precursor) and 1,3-diene substrate to decrease their interaction energy AEint (zeta) in 3,4-borocupration, thus promoting the 3,4-boracarboxylation. (c) 2025 Published by Elsevier B.V. on behalf of Chinese Chemical Society and Institute of Materia Medica, Chinese Academy of Medical Sciences.