Laser Flash Photolysis Study of Arylcyclopropylcarbenium Ions: Cation Stabilizing Abilities of Cyclopropyl and Phenyl Groups
作者:Wolfgang Kirmse、Birgit Krzossa、Steen Steenken
DOI:10.1021/ja960268j
日期:1996.1.1
Arylcyclopropylcarbenium ions, Ar(c-Pr)CH+, were generated as transient intermediates by laser flash photolysis (LFP) of trans-2,3-diphenylaziridinimines of aryl cyclopropyl ketones in 2,2,2-trifluoroethanol (TFE). The carbocations are thought to arise by way of diazo compounds and carbenes. Rate constants for the unimolecular decay in TFE and for the bimolecular reaction with methanol in TFE were
芳基环丙基碳鎓离子 Ar(c-Pr)CH+ 作为瞬态中间体通过激光闪光光解 (LFP) 在 2,2,2-三氟乙醇 (TFE) 中芳基环丙基酮的反式-2,3-二苯基氮丙啶亚胺生成。碳正离子被认为是通过重氮化合物和卡宾产生的。对于 Ar(c-Pr)CH+ 和类似的芳基苯基碳鎓离子 ArPhCH+,获得了 TFE 中单分子衰变和与 TFE 中甲醇双分子反应的速率常数。在这些系列中,发现环丙基和苯基的阳离子稳定能力在数量级上相似。然而,环丙基对增加电子需求的反应比苯基更强烈。因此,环丙基在 Ar = Ph 的阳离子稳定能力方面优于苯基,但在 Ar = 4-MeOC6H4 方面不如苯基。