“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.