Fused heteroaromatic dihydrosiloles: synthesis and double-fold modification.

An efficient method for the synthesis of fused heteroaromatic dihydrosiloles via Ni-catalyzed hydrosilylation/intramolecular Ir-catalyzed dehydrogenative coupling of the Si-H bond with the heteroaromatic C-H bond has been developed. The method is efficient for both electron-deficient and -rich heterocycles. It exhibits high functional group tolerance and good regioselectivity. Fused heteroaromatic dihydrosiloles can be smoothly halogenated and then oxidized or arylated. Application of these transformations allows obtaining highly functionalized heteroaromatic structures. A gram-scale synthesis of dihydropyridinosilole has also been accomplished using reduced amounts of Ni- and Ir-catalysts.