Ketene-forming elimination reactions from aryl phenylacetates promoted by R2NH in MeCN: effects of base-solvent andβ-phenyl group
作者:Sang Yong Pyun、Hyoun Jung Seok、Ju Chang Kim、Hwan Myung Kim、Bong Rae Cho
DOI:10.1002/poc.1233
日期:2007.9
Elimination reactions of C6H5C(R)HCO2C6H3-2-X-4-NO2 [R = H (1), Ph (2), X = H (a), Cl (b), NO2 (c)] promoted by R2NH in MeCN have been studied kinetically. The reactions are second-order and exhibit Brönsted β = 0.46–0.89 and |βlg| = 0.37–0.76 and an E2 mechanism is evident. When the base-solvent was changed from R2NH/R2NH–70 mol% MeCN(aq) to R2NH-MeCN, β and |βlg| values remained nearly the same within
C 6 H 5 C(R)HCO 2 C 6 H 3 -2-X-4-NO 2的消除反应[R = H(1),Ph(2),X = H(a),Cl(b)动力学研究了R 2 NH在MeCN中促进的NO 2(c)] 。的反应是二阶并且表现出布朗斯台德β = 0.46-0.89和| β LG | = 0.37–0.76,并且有一个E2机制是明显的。当基础溶剂从R 2 NH / R 2 NH –70 mol%MeCN(aq)变为R 2时NH-MeCN,β和| β LG | 值在实验误差范围内几乎保持不变。对于1和2的消除,β和| β LG | 尽管β- Ph组抑制了该速率,但其值几乎相同。值得注意的是,形成烯酮的过渡态对碱溶剂和β - R基团变化的相对不敏感性。版权所有©2007 John Wiley&Sons,Ltd.