Catalytic 1,4-selective hydrosilylation of pyridines and benzannulated congeners

Abstract

Radically different! The hydrosilylation of pyridines and quinolines is strictly 1,4-selective and likely involves an ionic one-step rather than the established radical two-step hydride transfer from a ruthenium(II) hydride complex onto the respective pyridinium and quinolinium ion intermediates (see scheme; Ar(F) =3,5-(CF3)2C6H3). Even 4-substituted substrates react highly regioselectively. Isoquinolines yield the 1,2-reduced heterocycles.

Keywords: N-heterocycles; SiH bond activation; homogeneous catalysis; hydrosilylation; regioselectivity.