Conjugate addition of O-silylatedketeneacetals to α,β-unsaturated carbonyl compounds in acetonitrile gave quantitative yields of the corresponding β-(alkoxycarbonyl)methyl O-silyl enolates . Site specific electrophilic substitutions of yielded the corresponding α-substituted β-(alkoxycarbonyl)-methylalkanones , , and .
α-alkylation and α-alkylidenation of carbonyl compounds by o-silylated enolate phenylthioalkylation
作者:Ian Paterson
DOI:10.1016/s0040-4020(01)86667-9
日期:1988.1
For many reactions next to a carbonyl group, the use of O-silylated enolatechemistry offers improvements in yield and selectivity over the corresponding reactions of Group I metal enolates. In the case of α-alkylation of carbonylcompounds, Lewis-acid (TiCL4 or ZnBr2) promoted phenylthioalkylation of O-silylated enolates 3 by α-chlorosulphides 4 (R3=H, Me, Prn, Pri, But, and Me3Si), followed by reductive
The synthesis of αβ-unsaturated ketones from β-silylenones and β-silylynones
作者:Ian Fleming、David A. Perry
DOI:10.1016/s0040-4020(01)93277-6
日期:——
Conjugate addition, followed by alkylation, bromination and desilyl-bromination make the β-silylketone (4) an a3d3-synthon (5) and the β-silylynone (6) a 2a3d3-synthon (7).
共轭加成,然后进行烷基化,溴化和去甲硅烷基溴化反应,使β-甲硅烷基酮(4)成为3 d 3-合成子(5)和β-甲硅烷基酮(6)成为2a 3 d 3-合成子(7)。
NEW SYNTHESIS OF METHYL 2-TRIORGANOSILYL-3-BUTENOATES AS A NEW SYNTHON OF 3-METHOXYCARBONYLALLYL ANION
Methyl 2-triorganosilyl-3-butenoates, which are selectively obtained from the carboxylation of the corresponding allylsilanes via allylic aluminates, react with various kinds of electrophiles to give γ substituted (E)-α,β-unsaturated esters in highly regio and stereoselective manner with the aid of a Lewis acid.
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。