Substituent and Solvent Effects on the Photosensitized Oxygenation of 5,6-Dihydro-1,4-oxathiins. Intramolecular Oxygen Transfer vs Normal Cleavage of the Dioxetane Intermediates
作者:F. Cermola、M. R. Iesce
DOI:10.1021/jo020008m
日期:2002.7.1
ketosulfoxides 7 and 8 depending on the nature of the substituent at C3 and on the reaction conditions. The normal fragmentation of dioxetanes 2 to 4 competes with an intramolecular oxygen transfer to ring sulfur, which leads to 7 and 8, presumably via the labile epoxides 5. This new pathway is promoted by electron-withdrawing groups at C3 and, for unsubstituted and monosubstituted amide derivatives 1h and 1i
单线态氧与各种取代的氧杂环丁烷1的反应产生二羰基化合物4和/或酮亚砜7和8,这取决于C 3上取代基的性质和反应条件。二氧环乙烷2到4的正常断裂与分子内的氧转移竞争成环硫,这大概是通过不稳定的环氧化物5导致的7和8。这种新的途径是由C3上的吸电子基团促进的,对于未取代的和单取代的酰胺衍生物1h和1i分别通过溶剂呈碱性。化学实验支持7为环氧化物5的中间体,而对于8为环氧化物的结论并不明确。但是,后者的形成似乎受到极性溶剂和C2上的阳离子稳定基团(如苯基或甲基)的帮助。