Experiment and Computational Study on the Regioselectivity of Nucleophilic Addition to Unsymmetrical <i>p</i>-Benzynes Derived from Bergman Cyclization of Enediynes
作者:Eshani Das、Shyam Basak、Anakuthil Anoop、Amit Basak
DOI:10.1021/acs.joc.8b00624
日期:2018.8.3
The regioselectivity in addition of nucleophiles to the p-benzyne intermediates derived from unsymmetrical aza-substituted enediynes via Bergman cyclization was studied. Computational studies [using UB3LYP/6-31G(d,p) level of theory] suggest that the p-benzyne intermediate retains its similar electrophilic character at the two radical centers even under unsymmetrical electronic perturbation, thus supporting
研究了通过Bergman环化反应将亲核试剂与非对称氮杂取代的二炔类化合物衍生的对-苄基中间体之间的区域选择性。计算研究[使用UB3LYP / 6-31G(d,p)的理论水平]表明,即使在不对称电子扰动下,p-苄基中间体仍在两个自由基中心保持相似的亲电子特性,从而支持了预测的亲核加成模型。p -benzyne提出(Perrin等佩兰和同事J.化学会会志。2007,129,4795-4799),后来由Alabugin和同事(Peterson等欧洲药典有机化学。化学,2013,2013,2505–2527)。但是,观察到的实验结果表明,区域选择性很小但很确定(〜5–25%),其程度随取代基的电子性质而变化。差的溶剂化卤化物离子浓度所产生的周围由于周围表面静电势(计算上计算)可能是在某些检验的这种选择性的可能因素之一2个基团中心的附近对- benzynes。然而,不能排除其他复杂的动力学问题,例如