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(sp 3 )–H bonds at the benzylic position in 4-alkylpyridines with hydrosilanes is described. The reaction proceeds in the presence of a catalytic amount of Ir 4 (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.