9-Hetero-10-boraanthracene-derived borinic acidcatalysts for regioselective activation of polyols

Abstract

Heteraborinine-derived borinic acids serve as efficient catalysts for regioselective monofunctionalization of di- and polyols. Arylborinic acids of this type, wherein the B–OH group is incorporated into a 6π electron system, display both improved catalytic activity for functionalization of diols and enhanced stability towards air oxidation relative to the ‘parent’ diphenylborinic acid (Ph₂BOH). These properties enable their applications at loadings as low as 0.1 mol% and without the need for a stabilizing precatalyst ligand (e.g., ethanolamine). Complexation studies, computation and kinetic data suggest that while the heteraborinine-derived borinic acids show significantly lower association constants with substrates than Ph₂BOH, this effect is more than compensated for by the increased nucleophilicity of their tetracoordinate diol adducts.