Iridium-catalyzed C(sp3)-H activation using imidazopyridine and pyridine as directing groups for selective silylation

A general and practically applicable strategy for chelation-assisted, iridium-catalyzed intermolecular silylation of C(sp 3 )-H bonds in 8-methylimidazo[1,2- a ]pyridines has been developed. This protocol enables direct, regioselective C(sp 3 )-H silylation in the absence of preactivation, affording ortho-silylated arylimidazo[1,2- a ]pyridines in high yields. Importantly, the reaction proceeds through a pentacyclic metallacycle intermediate, constituting the first example of imidazo[1,2- a ]pyridine-directed C(sp 3 )-H silylation. The method exhibits a broad substrate scope with good functional-group tolerance, delivering silylated products in yields up to 92% across a variety of hydrosilanes, 8-methylimidazo[1,2- a ]pyridines, and analogous methyl-substituted N -heterocycles. Its practical value was further verified by a gram-scale experiment and several representative downstream transformations of the products.