Ketene-Forming Eliminations from Aryl Phenylacetates Promoted by R<sub>2</sub>NH/R<sub>2</sub>NH<sub>2</sub><sup>+</sup> in Aqueous MeCN. Mechanistic Borderline between E2 and E1cb
作者:Bong Rae Cho、Hyun Cheol Jeong、Yoon Je Seung、Sang Yong Pyun
DOI:10.1021/jo025555m
日期:2002.7.1
Eliminationreactions of 2-X-4-NO2C6H3CH2C(O)OC6H3-2-Y-4-NO2 [X = H (1), NO2 (2)] promoted by R2NH/R2NH2+ in 70 mol % MeCN(aq) have been studied kinetically. The base-promoted eliminationsfrom 1 proceeded by the E2 mechanism when Y = Cl, CF3, and NO2. The mechanism changed to the competing E2 and E1cb mechanisms by the poorer leaving groups (Y = H, OMe) and to the E1cb extreme by the strongly electron-withdrawing