The second‐order rate constants (k) for reaction of 7‐chloro‐4‐nitrobenzofurazan 1 and 7‐methoxy‐4‐nitrobenzofurazan 2 with a series of nitroalkyl anions and several of para‐substituted phenoxide anions in aqueous solution at 20 °C have been reported. On the basis of the linear novel approach recently designed by Mayr and coworkers, the electrophilicity parameters E at the C‐5 position of the two nitrobenzofurazans 1 and 2 have been quantified and ranked on the comprehensive electrophilicity scale. Mayr's approach was found to correctly predict the rate constants for the addition of phenoxide anions at the C‐5 position of 1 and 2 witting a factor of <2. Analysis of the kinetic measurements using Brønsted's model shows that β_nuc values remain remarkably constant for changes in the nature of the substituent and that the σ‐complexation process is associated with high Marcus intrinsic barriers. In addition, satisfactory correlations between the log k_exp (k_exp values measured in this work for reactions of benzofurazans 1 and 2 with a series of phenoxide anions in aqueous solution at 20 °C) and log k_calcd (k_calcd values calculated from equation 1 using the electrophilicity parameters E of benzofurazans 1 and 2 and the previously published nucleophilicity parameters N and s_N of the phenoxide anions) with a slope very close to unity have been obtained and discussed.

中文翻译：

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σ络合过程中7‐L‐4‐硝基苯并呋喃的亲电反应：动力学研究和结构反应关系

在20°C的温度下，7-氯-4-硝基苯并呋喃山1和7-甲氧基-4-硝基苯并呋喃山2与一系列硝基烷基阴离子和几种对位取代的苯氧根阴离子反应的二级速率常数（k）已经报道。根据Mayr和同事最近设计的线性新颖方法，已对两个硝基苯并呋喃呋喃1和2的C-5位置的亲电参数E进行了量化，并列在综合亲电等级上。发现Mayr的方法可以正确预测在1和2的C-5位置添加酚盐阴离子的速率常数小于2的系数。使用布朗斯台德的模型示出了动力学测量的分析β _NUC值保持显着常数中的取代基的性质发生变化，而且σ络合处理进行高马库斯固有的障碍相关联。此外，log k _exp（在这项工作中，苯并呋喃酮1和2与一系列酚盐阴离子在20°C的水溶液中的反应中测得的k _exp值）与log k_计算出的k_值之间的令人满意的相关性（由方程式计算出的k_计算值） 1使用亲电参数E已获得并讨论了苯并呋喃酮1和2的合成以及先前发表的苯氧化物阴离子的亲核参数N和s _N（斜率非常接近于1）。