Reactivity of dianionic hexacoordinated silicon complexes toward nucleophiles: A new route to organosilanes from silica

Article abstract of DOI:10.1021/om00095a023

A general route for the preparation of organosilanes from silica is described. Depolymerization of silica is easily performed by chelating agents such as catechol in the presence of a base such as sodium methoxide with formation of a monomeric hexacoordinated complex [Si(o-O₂C₆H₄)₃]^2-2M ⁺ (1). The reaction of an excess of Grignard or organolithium reagent leads to the formation of R₄Si or R₃SiO-C₆H₄-(o-OH) depending on the nature of the reagent. Functional organosilanes R₃SiX can be prepared in a one-pot reaction from 1. Silane (SiH₄) is obtained in quantitative yield under very mild conditions from 1. Interestingly, hypervalent anionic silicon species 1 react efficiently with strong nucleophiles, the products obtained corresponding to the result of a nucleophilic displacement at silicon.