Rare-Earth-Catalyzed Selective Hydrosilylation of Iminocyclopropanes: Efficient Access to Azasilacyclopentanes

Catalytic hydrosilylation of iminocyclopropanes (ICPs) may selectively yield intriguing silicon-nitrogen heterocycles. Rare-earth alkyl complexes bearing silyl-binaphthyldiamide ligands have been synthesized and employed as catalysts for the hydrosilylation of ICPs with primary silanes. The catalytic reactions selectively yielded a series of azasilacyclopentanes in excellent yields (93-98%) with high selectivity (>99%) at room temperature. The catalytic reactions could be scaled up to the gram scale with 0.5 mol·% loadings of the catalysts. Notably, the azasilacyclopentanes could undergo facile alcoholysis and hydrolysis to give amine-functionalized siloxanes and silanols. The deuterium labeling and kinetic isotopic effect experiments as well as DFT calculations disclosed a catalytic cascade inter- and intramolecular hydrosilylation mechanism. The catalytic key intermediate silyl-binaphthyldiamine rare-earth hydride has been isolated and structurally characterized.