'Inverse' Frustrated Lewis Pairs – Activation of Dihydrogen with Organosuperbases and Moderate to Weak Lewis Acids

A new approach to intermolecular frustrated Lewis pairs (FLPs) that combines readily available bulky organosuperbases with moderate to weak boron-containing Lewis acids is reported. These so-called "inverse" FLPs are demonstrated to heterolytically cleave dihydrogen, allowing for the isolation and structural characterization of various phosphonium borohydride salts; two FLPs proved to be efficient catalyst's in the metal-free hydrogenation of N-benzylidenaniline.