Electrophilicities of Benzaldehyde-Derived Iminium Ions: Quantification of the Electrophilic Activation of Aldehydes by Iminium Formation
作者:Roland Appel、Saloua Chelli、Takahiro Tokuyasu、Konstantin Troshin、Herbert Mayr
DOI:10.1021/ja401106x
日期:2013.5.1
69 (Ar = p-MeOC6H4) to E = -8.34 (Ar = p-CF3), the iminium ions Ar-CH═NMe2(+) have almost the same reactivities as analogously substituted arylidenemalononitriles Ar-CH═C(CN)2 and are 10 orders of magnitude more reactive than the corresponding aldehydes. The rate constants for the reactions of iminium ions with amines and water in acetonitrile are 10(3)-10(5) times faster than predicted by the quoted
苯甲醛衍生的亚胺离子与 C-亲核试剂(烯胺、甲硅烷基化乙烯酮缩醛和烯醇醚)反应的速率常数已在 CH3CN 溶液中通过光度法确定,并用于确定由相关日志 k 定义的阳离子的亲电性参数 E (20°C) = s(N)(E + N) (Mayr, H.; et al. J. Am. Chem. Soc. 2001, 123, 9500-9512)。亲电性参数从 E = -10.69 (Ar = p-MeOC6H4) 到 E = -8.34 (Ar = p-CF3),亚胺离子 Ar-CH=NMe2(+) 具有与类似取代的亚芳基丙二腈 Ar- CH=C(CN)2 并且比相应的醛类反应性高 10 个数量级。亚胺离子与胺和水在乙腈中反应的速率常数比引用的相关性预测的快 10(3)-10(5) 倍,