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 enolate chemistry offers improvements in yield and selectivity over the corresponding reactions of Group I metal enolates. In the case of α-alkylation of carbonyl compounds, 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
对于羰基旁边的许多反应,使用O-甲硅烷基化的烯醇盐化学方法比第I组金属烯醇盐的相应反应提供了更高的产率和选择性。在羰基化合物,路易斯酸(的TiCl 4的α-烷基化的情况下,4或ZnBr 2)促进了phenylthioalkylation ö -silylated烯醇化物3由α-chlorosulphides 4(R 3 = H,Me中,镨Ñ,镨我,卜吨,和Me 3 Si),然后通过阮内镍从5→6进行还原性硫去除,被认为是此合成上重要的CC键形成步骤的可靠方法。一种替代硫消除途径经由5→7的亚砜可使羰基化合物进行区域和立体控制的α-亚烷基化。苯硫基烷基化反应适用于酮,醛,酯和内酯。