研究了在对位具有碱性氮取代基的全氟苯基卤化物与卤化氢水溶液的反应中,用氢置换了卤素取代基。对卤代N,N-二甲基全氟苯胺与各种卤化氢的反应行为以及对卤代全氟苯基三甲基铵三氟甲磺酸盐与亲核试剂和电子转移剂的反应行为表明,在酸性介质中脱卤加氢有两种可能的反应机理:通过正卤素的反应路线亲核进攻卤素取代基(S N X过程),以及电子转移和单分子消除卤离子(S RN)1个过程)。发现芳族环上的铵基和全氟取代对于进行这种脱卤代氢是必不可少的。
Aromatic polyfluoro-compounds. Part LIV. Copper-assisted nucleophilic displacement reactions of pentafluorohalogenobenzenes
作者:J. Burden、P. L. Coe、C. R. Marsh、J. C. Tatlow
DOI:10.1039/p19720000763
日期:——
Copper-assisted nucleophilic displacement reactions of pentafluorohalogenobenzenes have been investigated; in some cases exclusive halogen replacement occurs, and in others fluorine displacement and halogen reduction are observed. The effects of solvent and added ligands, notably thiourea, on the course of the reaction have been studied and a theory developed to explain the results observed.
The pentafluorohalogenobenzenes react with nucleophiles mainly at the position para to the halogen; ortho replacement occurs to a lesser extent and diminishes in the order C6F5Cl > C6F5Br > C6F5I∼C6F5H. This is rationalized in terms of an electronic effect, which involves electron repulsion by halogens in π-electron systems and also by steric factors.
所述pentafluorohalogenobenzenes与亲核试剂主要是在反应位置对位到卤素; 邻位置换的发生程度较小,并且以C 6 F 5 Cl> C 6 F 5 Br> C 6 F 5 I〜C 6 F 5 H的顺序减少。这在涉及电子排斥的电子效应方面是合理的π电子系统中的卤素以及空间因素。
KOBAYASHI, H.;SONODA, T.;TAKUMA, K., J. FLUOR. CHEM., 1985, 27, N 1, 1-22