Electrophilic Hydrosilylation of Electron-Rich Alkenes Derived from Enamines.

The low-electron count, air-stable, platinum complexes [Pt(IBu')(IBu)][BAr] (C1) (IBu=1,3-di-tert-butylimidazol-2-ylidene), [Pt(SiPh)(IBuPr)][BAr] (C2) (IBuPr=1-tert-butyl-3-iso-propylimidazol-2-ylidene), [Pt(SiPh)(IBuMe)][BAr] (C3), [Pt(GePh)(IBuPr)][BAr] (C4), [Pt(GePh)(IBuMe)][BAr] (C5) and [Pt(GeEt)(IBuMe)][BAr] (C6) (IBuMe=1-tert-butyl-3-methylimidazol-2-ylidene) are efficient catalysts (particularly the germyl derivatives) in both the silylative dehydrocoupling and hydrosilylation of electron rich alkenes derived from enamines. The steric hindrance exerted by the NHC ligand plays an important role in the selectivity of the reaction. Thus, bulky ligands are selective towards the silylative dehydrocoupling process whereas less sterically hindered promote the selective hydrosilylation reaction.