Conceptual Expansion of the Virtual Ligand Strategy toward the Design of Triarylborane Catalysts

Triarylboranes (BAr3) is one of the most important classes of Lewis acid catalyst. However, their molecular design still largely relies on the typical experimental trial-and-error strategy. Here, we introduced the virtual borane (VB) method—a novel computational approach for design of triarylborane catalysts—based on our virtual ligand strategy. In quantum chemical calculations, the VB reproduces the electronic and steric properties of various triarylboranes without handling their molecular structure explicitly. This in turn enables a rapid parameter-based optimization of catalyst properties, affording rational and quantitative guidelines for molecular design. The accuracy of the VB method was validated in reproducing not only simple Lewis bases affinities of various triarylboranes, but also complex energy diagrams of a borane-catalyzed reactions. The utility of the method was then demonstrated by the virtual borane-assisted optimization (VBAO), where optimal properties for transfer hydrosilylation was rapidly determined by numerical optimization of VB parameters. The VBAO calculation successfully suggested a superior catalyst, which was computationally validated.