Novel Synthesis of<i>γ</i>-Lactones Starting from<i>β</i>,<i>γ</i>-Unsaturated Carboxylic Esters
作者:Akio Kayano、Yumi Yajima、Motohiro Akazome、Makoto Fujita、Katsuyuki Ogura
DOI:10.1246/bcsj.68.3599
日期:1995.12
(methylthio)methyl p-tolyl sulfone. Upon the irradiation of a solution of 1 and benzophenone in an alcohol (R1R2CHOH), the 1-hydroxyalkyl radical (R1R2C–OH) was generated and added regiospecifically to the 3-position of 1 to form an adduct that led to a γ-lactone by spontaneous intramolecular condensation. Similarly, 2 reacted with the alcohol to give α-(ethoxycarbonyl)-γ-lactones. The alcohol, which is a high boiling
通过对 4-(甲硫基)-4-(对甲苯磺酰基)-3-丁烯酸酯 (1) 及其 2-(乙氧羰基) 衍生物 (2) 进行分子间自由基加成,实现了高取代 γ-内酯的新合成路线,它们很容易从(甲硫基)甲基对甲苯基砜制备。在 1 和二苯甲酮的醇溶液 (R1R2CHOH) 照射下,产生 1-羟基烷基 (R1R2C-OH) 并区域特异性地添加到 1 的 3-位以形成加合物,导致 γ-内酯通过自发的分子内缩合。同样,2与醇反应得到α-(乙氧羰基)-γ-内酯。醇是一种高沸点液体或固体,可以以溶液的形式使用(在乙腈中为 10 摩尔量),而不会大大降低反应效率。