Electronic and steric effects in theSNAr substitution reactions of substituted anilines with 2,4-dinitrophenyl 2,4,6-trinitrophenyl ether in acetonitrile
作者:Michael R. Crampton、Thomas A. Emokpae、Chukwuemeka Isanbor
DOI:10.1002/poc.997
日期:2006.1
2-position may result in considerable reductions in reactivity. These effects are more pronounced for the base-catalysed pathway and in 2,6-dimethylaniline the uncatalysed pathway takes all the reaction flux. In the case of the 2-fluoro substituent the electronic effect, strong inductive electron withdrawal, is dominant over steric effects. Copyright © 2005 John Wiley & Sons, Ltd.
报告了12个环取代苯胺与2,4-二硝基苯基2,4,6-三硝基苯基醚(1)在乙腈中。产物的形成,即相应取代的2,4,6-三硝基二苯胺,在没有通过碱催化和未催化途径观察到可检测量的中间体的情况下发生,并确定了这些过程的Hammettρ值。结果表明,尽管在苯胺的3-或4-位上的取代基仅具有很小的空间效应,但是在2-位上的烷基取代基可能导致反应性大大降低。对于碱催化的途径,这些作用更为明显,在2,6-二甲基苯胺中,未催化的途径吸收了所有反应通量。在2-氟取代基的情况下,电子效应,即强感应电子吸收,优于空间效应。版权所有©2005 John Wiley&Sons,Ltd.