A Pincer Ruthenium Complex for Regioselective C-H Silylation of Heteroarenes.

A pincer Ru(II) catalyst for the highly efficient undirected silylation of O- and S-heteroarenes with (TMSO)2 MeSiH and Et3 SiH is described, producing heteroarylsilanes with exclusive C2-regioselectivity, good functional-group tolerance, and high turnover numbers (up to 1960). The synthetic utility of the silylated products is demonstrated by Pd-catalyzed Hiyama-Denmark cross-coupling under mild conditions. One-pot, two-step silylation and coupling procedures have been also developed.