Thermal Isomerizations of 1-<sup>13</sup>C-2,2,3,3-<i>d</i><sub>4</sub>-Cyclopropane to Isotopically Labeled Trimethylene Diradicals, 1-Propylidenes, and Propenes
作者:John E. Baldwin、Linda S. Day、Stephanie R. Singer
DOI:10.1021/ja052678q
日期:2005.7.1
gas-phase thermal isomerizations of 1-13C-2,2,3,3-d4-cyclopropane lead to isotopically labeled propenes characteristic of both the traditional reaction mechanism involving a trimethylene diradical intermediate and a previously predicted, but never observed, path involving rate-limiting conversion of the cyclopropane to singlet 1-propylidenes, followed by a [1,2]-deuterium shift. The isomerizations give mixtures
1-13C-2,2,3,3-d4-环丙烷的气相热异构化产生同位素标记的丙烯,这些丙烯具有涉及三亚甲基双自由基中间体的传统反应机制和先前预测但从未观察到的路径,包括环丙烷向单线态 1-亚丙基的限速转化,然后是 [1,2]-氘转移。异构化产生 1-13C-2,3,3,3-d4-丙烯和 1-13C-1,2,3,3-d4-丙烯的混合物,这两种机制的产物特征可通过 13C 清楚地观察到1H}核磁共振谱。