The origin of regio- and enantioselectivity in the Rh/chiral 1,4-diene-catalyzed addition of phenylboronic acid to enones: insights from DFT

Abstract

A density functional theory study of the addition of phenylboronic acid to cyclohexenone catalyzed by chiral 1,4-diene–Rh(I) catalyst reveals that 1,4-addition is thermodynamically preferred. The enthalpy-driven enantioselection occurs during the carborhodation step and not the enone binding step, as previously proposed. The chiral ligand selectively destabilizes the disfavored transition state by making it “more early”.