Hydrogen activation by 2-boryl-N,N-dialkylanilines: a revision of Piers' ansa-aminoborane

Two 2-[bis(pentafluorophenyl)boryl]-N,N-dialkylanilines reported here exemplify a new class of intramolecular frustrated B/N Lewis pairs. A structure closely related to this class structure was synthesized in 2003 by Piers et al. but was unable to activate H-2. The new aminoboranes can activate hydrogen at near ambient conditions; besides, one of them can hydrogenate imines and enamines in a catalytic fashion demonstrating the validity of the original Piers' approach to hydrogen activation with ansa-aminoboranes.