An exploratory study of ring closures of aryl radicals onto cyclopropyl- and oxiranyl-isocyanate acceptors
作者:Patricia L. Minin、John C. Walton
DOI:10.1039/b405735j
日期:——
cis-1-bromo-(2-isocyanatocyclopropyl)benzene and (2-bromophenyl)-3-isocyanatooxirane, were prepared from the corresponding bromophenylcyclopropane and bromophenyloxirane carboxylic acids via Curtius rearrangements of the derived azides. The structure of the trans-2-(2-isocyanato)cyclopropylphenyl radical prevents cyclization, however, it was shown that isomerisation to the analogous cis-radical occurred, probably
对于2-(2-异氰酸根合)环丙基苯基和2-(2-异氰酸根合),研究了通过设计环化基团使其迅速向前断裂而使C中心自由基在异氰酸酯上的环闭合永久化的想法。氧杂环丁基苯基。自由基前体,反式和顺式-1-溴-(2-异氰酸根合环丙基)苯和(2-溴苯基)-3-异氰酸根合环氧乙烷,是由相应的溴苯基环丙烷和溴化苯基环氧乙烷羧酸通过衍生的叠氮化物的库尔修斯重排制备的。反式-2-(2-异氰酸根合)环丙基苯基基团的结构阻止环化,但是,表明发生了类似顺式-自由基的异构化,可能是由于双取代的环丙烷键的断裂,随后内旋使共振稳定了。激进的。然而,发现反-和顺-异氰酸根合环丙基化合物与氢化三丁基锡和三(三甲基甲硅烷基)硅烷的均相反应的主要产物是直接还原产物,反-(2-异氰酸根合环丙基)苯。仅检测到痕量的环化产物,可能是来自环丙烷前体的4,5-二氢苯并[c]氮杂-1-酮和来自环氧乙烷前体的5H-6-oxa-8-氮杂苯并环庚-