Synthesis and reactivity of bis(triethoxysilyl)methane, tris(triethoxysilyl)methane and some derivatives

Syntheses of new poly(trifunctional-silyl) alkanes, which are potent coupling agents of hybrid organic-inorganic materials have been thoroughly examined. Optimization of the Benkeser reaction using chloroform, trichlorosilane and tri-n-butylamine (respective ratios 1:4.5:3) afforded bis(trichlorosilyl)methane isolated as bis(triethoxysilyl)methane after ethanolysis (overall yield 60%). With nine equivalents of trichlorosilane, tris(trichlorosilyl)methane is preferentially formed, isolated as tris(triethoxysilyl)methane (30% yield). C-Substituted bis(triethoxysilyl) methanes were obtained after metallation of the alpha-carbon and trapping experiments with the corresponding alkyl halides. In the case of tris(triethoxysilyl)carbanion, only Mel and Br, were able to give the anticipated products. Unexpectedly, CO(2) insertion afforded the stable ketene, [(EtO)(3)Si](2)C=C=O. (C) 1998 Elsevier Science S.A. All rights reserved.