Magnesocenophane-Catalyzed Amine Borane Dehydrocoupling

The Lewis acidities of a series of n]magnesocenophanes ( 1 a – d ) have been investigated computationally and found to be a function of the tilt of the cyclopentadienyl moieties. Their catalytic abilities in amine borane dehydrogenation/dehydrocoupling reactions have been probed, and C1]magnesocenophane ( 1 a ) has been shown to effectively catalyze the dehydrogenation/dehydrocoupling of dimethylamine borane ( 2 a ) and diisopropylamine borane ( 2 b ) under ambient conditions. Furthermore, the mechanism of the reaction with 2 a has been investigated experimentally and computationally, and the results imply a ligand-assisted mechanism involving stepwise proton and hydride transfer, with dimethylaminoborane as the key intermediate.