The reaction of photochemically generated α-hydroxyalkyl radicals with alkynes: a synthetic route to γ-butenolides
作者:Niall W.A. Geraghty、Elaine M. Hernon
DOI:10.1016/j.tetlet.2008.11.067
日期:2009.2
and their subsequent carbon-carbon bond forming reaction with propiolate esters and acetylenedicarboxylates, gives a mixture of a β-(hydroxyalkyl)enoate, the result of a formal cis addition, and the unsaturated lactone (γ-butenolide) resulting from the spontaneous cyclization of the corresponding trans addition product. Treatment of the cis adduct with NBS converts it to the same lactone, and so the
由简单的无环和环状醇以及无环二醇进行光介导的α-羟烷基自由基生成,以及它们随后与丙酸酯和乙炔二羧酸酯形成碳-碳键的反应,生成了β-(羟烷基)烯酸酯的混合物,顺式加成,以及相应反式加成产物的自发环化产生的不饱和内酯(γ-丁烯内酯)。用NBS处理顺式加合物会将其转化为相同的内酯,因此该方法总体上构成了通往该重要结构单元的特别直接途径。环醇产生螺-γ-丁烯内酯。受支持的光介体的使用简化了产品隔离,并允许光介体的回收和再利用。