Regioselective Carboxylation of Silicon-Stabilized Allylic Carbanions and the Synthetic Utility of 2-Silyl-3-butenoates
作者:Hidemitsu Uno
DOI:10.1246/bcsj.59.2471
日期:1986.8
Carbanions of allylic dimethylphenylsilanes show remarkable regioselectivity toward both carboxylation with carbon dioxide and methylation with methyl iodide. Methylation of these compounds occurred preferentialy at α position, although allyltrimethylsilane and allyltriphenylsilane are known to give γ selectivity toward the same electrophiles. Moreover, their aluminum “ate” complexes react with carbon
烯丙基二甲基苯基硅烷的碳负离子对二氧化碳的羧化和甲基碘的甲基化都显示出显着的区域选择性。这些化合物的甲基化优先发生在 α 位,尽管已知烯丙基三甲基硅烷和烯丙基三苯基硅烷对相同的亲电试剂具有 γ 选择性。此外,它们的铝“ate”复合物在 a 位置与二氧化碳发生区域选择性反应,而与烯丙基部分的甲基取代模式无关。α-羧化烯丙基硅烷被证明是酯化后 3-(甲氧基羰基)烯丙基阴离子的有用合成子。
Regio- and Stereochemistry on the Electrophilic Trapping of Allylic Samariums Generated by Reductive Cleavage of Allylic Ethers with (C<sub>5</sub>Me<sub>5</sub>)<sub>2</sub>Sm(thf)<sub><i>n</i></sub>
The C-O bond of allylic benzyl ethers was selectively cleaved with Cp-2*Sm(thf)(n) to give allylic samarium complexes in good yields. Facility of their bond fission has been found to be comparable to that of the corresponding propargylic ethers intermolecularly, but lower intramolecularly. Regio- and stereochemistry on the electrophilic trapping of the allylic complexes thus generated remarkably depended on the nature of the electrophiles. They reacted with carbonyl compounds exclusively from the most substituted terminus of the allylic moieties to yield blanched homoallylic alcohols with anti diasteroselectivity. On the other hand, trapping with silyl chlorides produced linear allylic silanes. Here, a plausible mechanism to account for the difference is proposed.
Fleming, Ian; Higgins, Dick; Lawrence, Nicholas J., Journal of the Chemical Society. Perkin transactions I, 1992, # 24, p. 3331 - 3350
作者:Fleming, Ian、Higgins, Dick、Lawrence, Nicholas J.、Thomas, Andrew P.
DOI:——
日期:——
Chemistry of organosilicon compounds. 261. Photochemical 1,3-silyl migration in allylsilanes occurring with inversion of silyl configuration
作者:Mitsuo Kira、Takayuki Taki、Hideki Sakurai
DOI:10.1021/jo00285a002
日期:1989.11
Fleming Ian, Higgins Dick, Lawrence Nicholas J., Thomas Andrew P., J. Chem. Soc. Perkin Trans. 1, (1992) N 24, S 3331-3349
作者:Fleming Ian, Higgins Dick, Lawrence Nicholas J., Thomas Andrew P.