Evidence for heterolytic cleavage of a cyclic oxonium ylide: implications for the mechanism of the Stevens [1,2]-shift
作者:Seyedeh Nargess Hosseini、Jeffrey R. Johnston、F. G. West
DOI:10.1039/c7cc07716e
日期:——
Formation and rearrangement of several oxonium ylides containing cyclopropylcarbinyl migrating groups were studied. Efficient ring-contraction by [1,2]-shift to form cyclopropane-substituted cyclobutanones was observed, with no competing cyclopropane fragmentation. Substitution with the hypersensitive mechanistic probe (trans,trans-2-methoxy-3-phenylcyclopropyl)methyl led to cyclopropane fragmentation via an
研究了几种含有环丙基羰基迁移基团的氧代鎓盐的形成和重排。观察到通过[1,2]-移位的有效环收缩以形成环丙烷取代的环丁酮,而没有竞争性的环丙烷断裂。用超灵敏的机械探针(反式,反式-2-反甲氧基-3-苯基环丙基)甲基取代通过明显的杂合途径导致环丙烷断裂,为叶立德裂解产生的离子对中间体提供了第一个证据,并提出了可能的替代性杂合机理史蒂文斯[1,2]班次。