Computational mechanism investigation of bismuth (BiIII/BiV) redox-catalyzed fluorination of arylboronic esters

Abstract

Recently, the Cornella group has achieved bismuth redox-catalyzed fluorination of arylboronic esters by using heavier main group elements to simulate the transition metal catalytic cycle method. Despite the great efforts made by the experimental group, details regarding the mechanism remained unclear. In this work, detailed DFT calculations were carried out to elucidate the principal features of this transformation. The results reveal the following: (1) the entire conversion is thermodynamically favorable, with a free energy decrease of 124.4 kcal mol⁻¹; (2) the activator KF not only is beneficial to assisting the dissociation of BF₃ on the bismuth catalyst to facilitate transmetallization, but may also be a potential promoter of BF₄⁻ dissociation in the reductive elimination step; (3) the sulfone fragment is favorable for reductive elimination; and (4) pyridyl fluoride may be responsible for the smooth progress of the oxidative addition.