Synthetic studies on O-heterocycles via cycloadditions. Part 2. Adducts from styrene oxides
作者:Paul Clawson、Patricia M. Lunn、Donald A. Whiting
DOI:10.1039/p19900000159
日期:——
The styrene oxides (14) and (15), bearing electron-withdrawing functions, readily undergo thermal and photochemical (triplet sensitised) dipolar cycloadditions with simple electron-deficient olefins, regioselectively in the case of methyl acrylate. However, cycloadditions with 5-arylbutenolides as dipolarophiles, required for lignan synthesis, could not be effected in significant yield. A new short
带有吸电子功能的苯乙烯氧化物(14)和(15)容易与简单的缺电子烯烃发生热和光化学(三重感光)偶极环加成反应,在丙烯酸甲酯的情况下具有区域选择性。然而,木脂素合成所需的以5-芳基丁烯内酯作为双极性亲和剂的环加成反应不能以显着的产率进行。设计了一条新的5-芳基丁-2-烯内酯的短途路线。二氢和四氢呋喃加合物(18d),(19d)和(20d)全部在碱中裂解成二烯醇腈(25)。