Catalyst-free formation of 1,4-diketones by addition of silyl enolates to oxyallyl zwitterions in situ generated from α-haloketones
作者:Juan Luo、Qihua Jiang、Hao Chen、Qiang Tang
DOI:10.1039/c5ra12244a
日期:——
IV. Thus, a variety of metal-catalyzed coupling reactions have been developed to avoid the undesired reaction when attempting the preparation of 1,4-diketones. We found that the oxyallyl zwitterions in situ generated from α-haloketones enabled the addition of silyl enolates to the α-carbonyl position to exclusively form 1,4-diketones in weakly basic conditions. Various types of silyl enolates and α-haloketones
此处报道的是甲硅烷基烯醇盐和α-卤代酮的未催化反应,独家形成1,4-二酮。烯醇盐I本来就更可能在羰基碳上与α-卤代酮II反应生成卤代醇衍生物III或2-(2-氧代乙基)-环氧乙烷IV。因此,已开发出多种金属催化的偶联反应,以避免在尝试制备1,4-二酮时发生不希望的反应。我们发现原位的羟烯丙基两性离子由α-卤代酮生成的产物能够在弱碱性条件下将甲硅烷基烯醇酯添加到α-羰基位置上,从而专门形成1,4-二酮。各种类型的甲硅烷基烯酸酯和α-卤代酮被用于无催化剂偶联。