Silicon-Promoted Carbon-Carbon Bond Formation between Ketones and Allyl- or Vinylsilanes Catalyzed by Manganese(IV) Dioxide
摘要:
The influence of silicon on the carbon-carbon bond formation was investigated by use of various silylalkenes to react with ketones. Treatment of an allylsilane (CH2=CHCH(2)SiMe(m)Ph(n); m + n 3) with various ketones (20 equiv) in the presence of MnO2 (2.0 equiv) and a drop of acetic acid at 140 degrees C in a sealed tube produced the corresponding hydrogen atom transfer adducts in 54-85% yields. Performance of the same reactions by replacement of the allylsilane with a vinylsilane (i.e., CH2=CHSiMe(3) and CH2=CHSiMeEt(2)) afforded adducts in 59-75% yields. Furthermore, reaction of diallyldimethylsilane with acetone or 3-methyl-2-butanone under the same conditions afforded 4-(3,3-dimethyl-3-silacyclohexyl)butan-2-one (81%) and 4-(3,3-dimethyl-3-silacyclohexyl)-3,3-dimethylbutan-2-one (65%), respectively. The results indicate that the alpha- and the beta-electronic effects of a silicon atom promoted the C-C bond formation, while the regioselectivity came from the steric effect of the silyl group.
Organometallic photochemistry photochemistry of some acyclic ketosilanes
作者:Henry G. Kuivila、Perry L. Maxfield
DOI:10.1016/s0022-328x(00)81715-5
日期:1967.10
Photolysis of a series of silyl ketones with the general structure (CH3)3Si(CH2)nCOR with n = 0–4, R = C6H5 and with n = 0–3, R = CH3 has been investigated. When n = 3 or 4 a major course of reaction is the Type II cleavage. When R = CH3 and n = 3 a substantial amount of cyclobutanol formation occurs; none is detected when R = C6H5. If n = 2 and R = C6H5 the only photoreactions established are reductive
具有通式结构的一系列甲硅烷基酮的光解(CH 3)3 SI(CH 2)ñ COR与Ñ = 0-4,R = C 6 H ^ 5,并用Ñ = 0-3,R = CH 3已经调查。当n = 3或4时,反应的主要过程是II型裂解。当R = CH 3且n = 3时,会形成大量的环丁醇。当R = C 6 H 5时,没有检测到。如果n = 2且R = C 6 H 5唯一建立的光反应是还原性烷基化(通过溶剂环己烷)和羰基亚甲基键的裂解。如果R = CH 3,则可以在羰基-亚甲基键的初始裂解的基础上使所有分离出的产物合理化。在惰性溶剂中,n = 1或0的化合物几乎不会发生光化学分解。但是,每种化合物都容易进行光催化水解以形成三甲基硅烷醇和醛或酮。
Aluminiumalkyle mit heteroatomen
作者:Georg Sonnek、Karl-Gunter Baumgarten、Heinz Reinheckel、Stanislaw Pasynkiewicz、Kazimierz B. Starowieyski
DOI:10.1016/s0022-328x(00)85544-8
日期:1978.4
Aliphatic nitriles react with tris(3-trimethylsilylpropyl)aluminium forming 1-trimethylsilyl-alkan-4-ones upon hydrolysis while benzonitrile is reduced to benzaldehyde even at room temperature. The properties of the complex and the course of the reaction have been investigated spectroscopically.
Addition of trimethylsilylmethylmagnesium chloride to α, β-unsaturated carbonyls
作者:Richard T. Taylor、James G. Galloway
DOI:10.1016/s0022-328x(00)82282-2
日期:1981.11
Reactions of α,β-unsaturated carbonyl compounds with Me3SiCH2MgCl, prepared from chloromethyltrimethylsilane [1], were examined. Unlike its lithium counterpart (Me3SiCH2Li), which adds to α,β-unsaturatedketones in the 1,2-sense, the Grignardreagent afforts γ silanes via a 1,4-addition sequence. This tendency is accentuated by the addition of Cu2Br2. Addition of the Grignardreagent to α,β-unsaturated
考察了α,β-不饱和羰基化合物与由氯甲基三甲基硅烷[1]制得的Me 3 SiCH 2 MgCl的反应。不同于其锂对应物(Me 3 SiCH 2 Li),后者会在1,2-感官中添加α,β-不饱和酮,格氏试剂通过1,4-添加序列促进γ硅烷的合成。通过添加Cu 2 Br 2加剧了这种趋势。将格氏试剂添加到α,β-不饱和醛中可得到简单的1,2-加成产物。
The preparation of some 4-organosilicon derivatives of 7-hydroxycoumarin
作者:C. Eaborn、B.N. Ghose、D.R.M. Walton
DOI:10.1016/s0022-328x(00)91267-1
日期:1974.1
Some organosilicon-substituted ketones have been converted into β-ketoesters, and hence into 4-derivatives of 7-hydroxycoumarin.