Hosseini Seyedeh Nargess, Johnston Jeffrey R, West F G
Department of Chemistry, University of Alberta, E3-43 Gunning-Lemieux Chemistry Centre, Edmonton, Alberta T6G 2G2, Canada.
Chem Commun (Camb). 2017 Nov 23;53(94):12654-12656. doi: 10.1039/c7cc07716e.
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 apparent heterolytic pathway, providing the first evidence for ion pair intermediates from ylide cleavage, and suggesting a possible alternative heterolytic mechanism for the Stevens [1,2]-shift.
研究了几种含有环丙基甲基迁移基团的氧化鎓叶立德的形成和重排。观察到通过[1,2]迁移进行有效的环收缩以形成环丙烷取代的环丁酮，没有竞争性的环丙烷断裂。用超灵敏机理探针（反式，反式-2-甲氧基-3-苯基环丙基）甲基取代导致通过明显的异裂途径发生环丙烷断裂，为叶立德裂解产生离子对中间体提供了首个证据，并暗示了史蒂文斯[1,2]迁移可能存在的另一种异裂机理。
