Iridium-Catalyzed Regioselective C(sp3)–H Silylation of 4‑Alkylpyridines at the Benzylic Position with Hydrosilanes Leading to 4‑(1-Silylalkyl)pyridines

The regioselective silylation of C­(sp3)–H bonds at the benzylic position in 4-alkylpyridines with hydrosilanes is described. The reaction proceeds in the presence of a catalytic amount of Ir4(CO)12 or Ir­(acac)­(CO)2, which possess CO as a ligand, or [Ir­(OMe)­(cod)]2 under 1 atm of CO. After optimizing the reaction conditions, by using other pyridine derivatives, such as 3,5-dimethylpyridine, as additives, the low product yields of 2-substituted 4-methylpyridines were improved markedly.