Thermal fragmentation of 2-azidobenzo[b]thiophene in the presence of alkenes: a new synthetic route to 1-(2-benzo[b]thienyl)aziridines and/or thiochroman-4-carbonitriles
作者:Piero Spagnolo、Paolo Zanirato
DOI:10.1039/p19880003375
日期:——
Mild thermal fragmentation of 2-azidobenzo[b]thiophene in the presence of olefins results in the formation of 1-(2-benzo[b]thienyl)aziridines and/or 4-cyanothiochromans in fairly good yields. The formation of aziridines, at the expense of thiochromans, is favoured by electron-poor olefins and by a decrease in the reaction temperature. Evidence is presented in favour of a singlet nitrene intermediate
在烯烃存在下2-叠氮基苯并[ b ]噻吩的温和热裂解导致形成1-(2-苯并[ b ]噻吩基)氮丙啶和/或4-氰基噻吩并以相当好的收率形成。贫电子的烯烃和反应温度的降低有利于以硫代色烷为代价形成氮丙啶。提供了有利于单线态氮烯中间体的证据,该中间体加成到烯烃双键上或经历开环反应以得到被存在的烯烃所俘获的邻-喹啉类亚乙基硫酮。这些发现提供了第一个由2-nitreno取代的噻吩开环的例子。