SYNTHESIS AND REACTIVITY OF BIS(TRIETHOXYSILYL)METHANE, TRIS(TRIETHOXYSILYL)METHANE AND SOME DERIVATIVES

Syntheses of new poly(trifunctional-silyl) alkanes, which are potent c oupling agents of hybrid organic-inorganic materials have been thoroug hly examined. Optimization of the Benkeser reaction using chloroform, trichlorosilane and tri-n-butylamine (respective ratios 1:4.5:3) affor ded bis(trichlorosilyl)methane isolated as bis(triethoxysilyl)methane after ethanolysis (overall yield 60%). With nine equivalents of trichl orosilane, tris(trichlorosilyl)methane is preferentially formed, isola ted as tris(triethoxysilyl)methane (30% yield). C-Substituted bis(trie thoxysilyl) methanes were obtained after metallation of the alpha-carb on and trapping experiments with the corresponding alkyl halides. In t he case of tris(triethoxysilyl)carbanion, only Mel and Br, were able t o give the anticipated products. Unexpectedly, CO2 insertion afforded the stable ketene, [(EtO)(3)Si](2)C=C=O. (C) 1998 Elsevier Science S.A . All rights reserved.