Intermolecular C–H silylations of arenes and heteroarenes with mono-, bis-, and tris(trimethylsiloxy)hydrosilanes: control of silane redistribution under operationally diverse approaches

Abstract

Efficient catalytic protocols for C–H silylations of arenes and heteroarenes with sterically and electronically different hydrosiloxysilanes are disclosed. The silylations are catalyzed by a well-defined Rh-complex (1 mol%), derived from [Rh(1,5-hexadiene)Cl]₂ and a bulky BINAP type ligand. This catalyst not only promotes C–Si bond formation affording the desired products in up to 95% isolated yield, but also can suppress the silane redistribution side reactions of HSiMe₂(OTMS). The protocol can also be applied for the C–H silylations of more reactive HSiMe(OTMS)₂ with a much lower catalyst loading (0.25 mol%) and even with sterically demanding HSi(OTMS)₃. The steric bulk of the arene substituent and hydrosiloxysilane is a major factor in determining the regioselectivity and electronic effect as secondary. The current method can be performed under operationally diverse conditions: with/without a hydrogen scavenger or solvent.