Competitive 1,2- and 1,5-Hydrogen Shifts Following 2-Vinylbiphenyl Photocyclization
作者:Frederick D. Lewis、Meledathu C. Sajimon、Xiaobing Zuo、Michael Rubin、Vladimir Gevorgyan
DOI:10.1021/jo051730y
日期:2005.12.1
occur via a two-step mechanism: photocyclization to form an unstable 8a,9-dihydro-phenanthrene intermediate, followed by exothermic unimolecular isomerization to a 9,10-dihydrophenanthrene. The mechanism of the hydrogen shift process has been investigated using deuterated derivatives of 2-isopropenylbiphenyl and 2,6-diphenylstyrene. 1H NMR analysis of the photoproducts indicates that the thermally allowed
已经提出2-乙烯基联苯及其衍生物的光环化通过两步机理发生:光环化以形成不稳定的8a,9-二氢菲中间体,然后放热单分子异构化为9,10-二氢菲。已经使用2-异丙烯基联苯和2,6-二苯基苯乙烯的氘代衍生物研究了氢转移过程的机理。1个光产物的1 H NMR分析表明,热允许的1,5-氢或氘转移是次要的产物形成途径,而异常的双1,2氢或氘转移是主要的产物形成途径。已经通过计算探索了光环化和氢转移过程的势能面。预测的1,5-班次的势垒将大大低于1,2-班次的势垒。提出了发生1,2-氢或氘迁移的替代机制。