Synthesis, Structure, and Reactivity of a Terminal Magnesium Hydride Compound with a Carbatrane Motif, [Tism^PrⁱBenz]MgH: A Multifunctional Catalyst for Hydrosilylation and Hydroboration

The tris[(1-isopropyl­benz­imid­azol-2-yl)­dimethyl­silyl)]­methyl ligand, [TismPriBenz], has been employed to form the magnesium carb­atrane compound, [TismPriBenz]­MgH, which possesses a terminal hydride ligand. Specifically, [TismPriBenz]­MgH is obtained via the reaction of [TismPriBenz]­MgMe with PhSiH3. The reactivity of [TismPriBenz]­MgMe and [TismPriBenz]­MgH allows access to a variety of other structurally characterized carb­atrane derivatives, including [TismPriBenz]­MgX [X = F, Cl, Br, I, SH, N­(H)­Ph, CH­(Me)­Ph, O2CMe, S2CMe]. In addition, [TismPriBenz]­MgH is a catalyst for (i) hydro­silyl­ation and hydro­boration of styrene to afford the Markov­nikov products, Ph­(Me)­C­(H)­SiH2Ph and Ph­(Me)­C­(H)­Bpin, and (ii) hydro­boration of carbo­diimides and pyridine to form N-boryl form­amidines and N-boryl 1,4- and 1,2-dihydro­pyridines, respectively.