Beschreibung:
<jats:title>Abstract</jats:title><jats:p>The Lewis acidities of a series of [<jats:italic>n</jats:italic>]magnesocenophanes (<jats:bold>1 a</jats:bold>–<jats:bold>d</jats:bold>) 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 C[1]magnesocenophane (<jats:bold>1 a</jats:bold>) has been shown to effectively catalyze the dehydrogenation/dehydrocoupling of dimethylamine borane (<jats:bold>2 a</jats:bold>) and diisopropylamine borane (<jats:bold>2 b</jats:bold>) under ambient conditions. Furthermore, the mechanism of the reaction with <jats:bold>2 a</jats:bold> 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.</jats:p>