Cobalt-Catalyzed Asymmetric Synthesis of gem-Bis(silyl)alkanes by Double Hydrosilylation of Aliphatic Terminal Alkynes

Chiral organosilanes are of great value in asymmetric synthesis, functional materials, and medicinal chemistry. Compared with single-silyl compounds, bis(silyl) ones are understudied because of the lack of the efficient synthetic protocols. The development of efficient synthetic approaches to access bis(silyl) compounds is highly desirable for studying their basic properties and potential utilities. Here, a cobalt-catalyzed sequential double hydrosilylation of aliphatic alkynes was developed to synthesize highly enantioenriched gem-bis(silyl)alkanes. This protocol used simple aliphatic alkynes and silanes to construct valuable chiral gem-bis(silyl)alkanes. The control experiments, isotopic labeling experiments, kinetic studies, and density functional theory calculations were conducted to elucidate the reaction mechanism. The synthetic versatility of gem-bis(silyl)alkanes was demonstrated by the synthesis of chiral organosilanols, alpha-hydroxysilanes through selective C-Si bond transformation and hydrosilylation of alkynes to construct chiral silanes containing adjacent C-stereocenter and Si-stereocenter.