Cobalt-Catalyzed Asymmetric Hydrogenation of Vinylsilanes with a Phosphine-Pyridine-Oxazoline Ligand: Synthesis of Optically Active Organosilanes and Silacycles

The asymmetric hydrogenation of vinylsilanes catalyzed by a new C-1-symmetric phosphine-pyridine-oxazoline cobalt complex is described. The method provides an efficient approach to chiral tertiary silanes with enantioselectivities up to 99% ee. Furthermore, the o-methylsubstituted benzylic silane products undergo ruthenium-catalyzed dehydrogenative silylation to produce chiral benzosilolanes in high yields without racemization of the stereogenic center alpha to the quaternary Si atom.