Triazine-Based Cationic Leaving Group: Synergistic Driving Forces for Rapid Formation of Carbocation Species
作者:Hikaru Fujita、Satoshi Kakuyama、Shuichi Fukuyoshi、Naoko Hayakawa、Akifumi Oda、Munetaka Kunishima
DOI:10.1021/acs.joc.8b00331
日期:2018.4.20
nic acid (∼200 mol %). Considerable rate acceleration of benzylation, allylation, and p-nitrobenzylation was observed as compared to the reactions with less than 100 mol % of the acid catalyst. The triazine-based leaving group showed superior p-nitrobenzylation yield and stability in comparison to common leaving groups, trichloroacetimidate and bromide. A plausible reaction mechanism (the cationic
已经开发出一种新的基于三嗪的阳离子离去基团,用于酸催化O-和C-亲核试剂的烷基化。在三氟甲磺酸(〜200 mol%)的存在下,碳正离子物质的快速生成涉及两种协同驱动力,即稳定的C═O键形成和电荷-电荷排斥作用。与使用少于100mol%的酸催化剂的反应相比,观察到苄基化,烯丙基化和对硝基苄基化的显着速率加速。基于三嗪的离去组显示出优异的p与常见的离去基团,三氯乙酰亚胺酸酯和溴化物相比,-硝基苄基化的收率和稳定性。在机理和动力学研究,NMR实验和计算的基础上,提出了合理的反应机理(阳离子离去基团途径)。