Formation of Enamines via Catalytic Dehydrogenation by Pincer-Iridium Complexes

Efficient pincer-ligated iridium catalysts are reported for the dehydrogenation of simple tertiary amines to give enamines, and for the dehydrogenation of β-functionalized amines to give the corresponding 1,2-difunctionalized olefins. Experimentally determined kinetic isotope effects in conjunction with DFT-based analysis support a dehydrogenation mechanism involving initial pre-equilibrium oxidative addition of the amine α C-H bond followed by rate-determining elimination of the β-C-H bond.