Lewis acid-promoted reaction of β,γ-unsaturated α,α-dimethoxy esters with silyl nucleophiles
作者:Hideyuki Sugimura、Hiiro Miyazaki、Yui Makita
DOI:10.1016/j.tetlet.2012.06.078
日期:2012.8
The Lewis acid-promoted reaction of β,γ-unsaturated α,α-dimethoxy esters, which are easily prepared by the acetalization of β,γ-unsaturated α-keto esters, with silyl nucleophiles is presented. By employing trimethylsilyl enolate and allyltrimethylsilane as nucleophiles, the BF3-promoted reactions of a series of β,γ-unsaturated α,α-dimethoxy esters bearing aromatic and aliphatic substituents proceeded
提出了路易斯酸促进的β,γ-不饱和α,α-二甲氧基酯与甲硅烷基亲核试剂的缩合反应,该反应很容易通过β,γ-不饱和α-酮酯的乙缩醛化反应制得。通过使用烯丙基三甲基甲硅烷基酯和烯丙基三甲基硅烷作为亲核试剂,一系列带有芳族和脂族取代基的β,γ-不饱和α,α-二甲氧基酯的BF 3促进反应以SN2'方式在γ位进行,以提供γ-具有高区域选择性的高产率的取代的α,β-不饱和α-甲氧基酯。相反,使用三甲基甲硅烷基氰化物的反应主要在α位发生,而甲硅烷基氢化物的反应导致α-和γ-区域异构体的混合物有利于γ-取代产物。