Ruthenium‐Catalyzed Dimethylamineborane Dehydrogenation: Stepwise Metal‐Centered Dehydrocyclization

Amine–borane dehydrogenation: Ruthenium PNP amido pincer complex I catalyzes the dehydrocoupling of dimethylamineborane to cyclic dimer (Me2NBH2)2. The results are in agreement with a mechanism including initial alternative dehydrogenation to aminoborane Me2NBH2 versus metal-centered BN coupling via diborazane Me2HNH2BMe2NBH3. Formation of borametallacycle II, which features a rare four-membered Ru–N–B–H ring, results in considerable slowdown of the catalytic activity.