- The synthesis of chlorosilanes from alkoxysilanes, silanols, and hydrosilanes with bulky substituents
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We have found that commercially important trialkylchlorosilanes can readily be synthesized by the reaction of alkoxysilanes, silanols, and hydrosilanes with aqueous concentrated hydorochloric acid. Treatment of trialkylalkoxysilanes bearing the bulky alkyl substituents, such as the i-Pr, sec-Bu, tert-Bu, and cyclo-Hex group, with 35% aqueous hydrochloric acid afforded the corresponding trialkylchlorosilanes in excellent yields. Similar treatment of trialkylsilanols with 35% aqueous hydrochloric acid also gave trialkylchlorosilanes in almost quantitative yields. The reaction of methyltrichlorosilane and dimethyldichlorosilane with alkyl-Grignard reagents bearing a bulky alkyl group, followed by treatment of the resulting mixtures with aqueous concentrated hydrochloric acid, produced the respective dialkylmethyl- and alkyldimethylchlorosilanes in high yields. Treatment of trialkylhydrosilanes with concentrated hydrochloric acid in the presence of a palladium catalyst afforded trialkylchlorosilanes in high yields.
- Masaoka, Shin,Banno, Tadashi,Ishikawa, Mitsuo
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p. 174 - 181
(2007/10/03)
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- Versatile method for introduction of bulky substituents to alkoxychlorosilanes
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The reactions of various alkoxytrichlorosilanes prepared in situ from tetrachlorosilane and alcohols, with Grignard reagents bearing a bulky substituent such as the isopropyl, sec-butyl, and cyclohexyl group afforded triisopropyl-, tri(sec-butyl)-, and tricyclohexylalkoxysilane in high yields. The reactions of n-butoxytrichlorosilane with these Grignard reagents produced triisopropyl-, tri(sec-butyl)-, and tricyclohexyl(n-butoxy)silane in 94%, 96%, and 92% yields, respectively. Methoxymethyldichlorosilane reacted with the same Grignard reagents to give diisopropyl-, di(sec-butyl)-, and dicyclohexylmethoxymethylsilane in 84%, 83%, and 83% yields. Treatment of methoxydimethylchlorosilane with the Grignard reagents readily afforded isopropyl-, sec-butyl-, and cyclohexylmethoxydimethylsilane in excellent yields. Similar treatment of methoxydimethylchlorosilane with tert-butylmagnesium chloride gave tert-butylmethoxydimethylsilane in 62% yield.
- Masaoka, Shin,Banno, Tadashi,Ishikawa, Mitsuo
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p. 182 - 192
(2007/10/03)
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- Steroidal Silicon Side-Chain Analogues as Potential Antifertility Agents
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A number of silicon-substituted analogues of ethynylestradiol that exhibit modified and enhanced biological activities have been synthesized.Particularly noteworthy are a group of estradiol analogues that exhibit high antifertility potency and markedly reduced estrogenic activity.The best compounds synthesized are 17α-estradiol (5) and 17α-estradiol (33), which show a separation of antifertility from estrogenic activity in the rat.The results of structure-activity studies indicate a good correlation between the observed biological activities and the calculated van der Waals volumes of the three variable silicon substituents.
- Peters, Richard H.,Crowe, David F.,Tanabe, Masato,Avery, Mitchell A.,Chong, Wesley K. M.
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p. 646 - 652
(2007/10/02)
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