作者:G. David Mendenhall、John D. Protasiewicz、Carl E. Brown、K. U. Ingold、J. Lusztyk
DOI:10.1021/ja00084a012
日期:1994.3
cyclization of the 2-formylbenzoyl radical (reaction 2) is shown to be a highly favored process relative to the alternative, 4-exo-trig ring closure. This evidence comes from product studies, including ESR and laser flash photolysis studies of transient radical intermediates, from a nitroxide trapping measurement of the rate constant for cyclization of the 2-formylbenzoyl radical, viz., k 2 =2×10 8 s -1 at45
2-甲酰基苯甲酰基自由基的 5-内环化(反应 2)被证明是相对于替代的 4-外-trig 闭环非常有利的过程。该证据来自产品研究,包括瞬态自由基中间体的 ESR 和激光闪光光解研究,来自氮氧化物捕获测量 2-甲酰基苯甲酰基自由基环化的速率常数,即 k 2 =2×10 8 s -1在 45 o C 下,并根据 5-endo 环化与 4-exo-trig 环化的估计有利焓变化。这表明最初形成的 2-甲酰基苯甲酰基构象异构体中甲酰基的旋转可能是该环化反应的限速步骤