Metal‐Free Catalytic Hydrogenation of Enamines, Imines, and Conjugated Phosphinoalkenylboranes

The metal-free hydrogen activator 1 catalyzes the unique P/B hydrogenation of the frustrated Lewis pair 3, which itself is inactive toward H2 under the applied conditions, to yield the hydrogenation product 4. System 1/2 (5 mol %) also catalyzes the hydrogenation of a bulky ketimine and of enamines under mild conditions (2.5 bar H2, RT) to yield the respective amines.