Mechanism of Alkoxy Groups Substitution by Grignard Reagents on Aromatic Rings and Experimental Verification of Theoretical Predictions of Anomalous Reactions
作者:Gonzalo Jiménez-Osés、Anthony J. Brockway、Jared T. Shaw、K. N. Houk
DOI:10.1021/ja4015937
日期:2013.5.1
The mechanism of direct displacement of alkoxy groups in vinylogous and aromatic esters by Grignard reagents, a reaction that is not observed with expectedly better tosyloxy leaving groups, is elucidated computationally. The mechanism of this reaction has been determined to proceed through the inner-sphere attack of nucleophilic alkyl groups from magnesium to the reacting carbons via a metalaoxetane
通过计算阐明了插烯酯和芳香酯中烷氧基被格氏试剂直接置换的机制,该反应在预期更好的甲苯磺酰氧基离去基团中未观察到。该反应的机理已确定为通过金属氧杂环丁烷过渡态从镁到反应碳的亲核烷基的内球攻击进行。与反应的烷氧基和羰基形成强镁螯合物决定了观察到的反应性和选择性。研究了酯、酮和醛取代基的影响。在某些情况下,计算预测的产物形成与之前报道的不同。这些预测随后得到了实验验证。论证了研究实际系统而不是作为计算系统的简化模型的重要性。