从2-溴乙基溴化菲啶鎓与一系列伯胺的反应中已分离出一类新型的菲啶鎓衍生物,收率很高。反应路径是前所未有的,通过三个级联的步骤进行:在杂芳环体系和环化的亚胺部分的伯胺的亲核攻击,以形成一个五元环,随后氢化物损失,得到rearomatized二氢ħ -咪唑并[1,2- f ]菲啶鎓衍生物。进行了一系列NMR相转移实验以阐明机理途径,并且该方法已经通过使用N-溴代琥珀酰亚胺作为助氧化剂的双相系统进一步发展。该方法也已扩展到其他N-杂环阳离子衍生物,例如喹啉鎓和喹唑啉鎓。
从2-溴乙基溴化菲啶鎓与一系列伯胺的反应中已分离出一类新型的菲啶鎓衍生物,收率很高。反应路径是前所未有的,通过三个级联的步骤进行:在杂芳环体系和环化的亚胺部分的伯胺的亲核攻击,以形成一个五元环,随后氢化物损失,得到rearomatized二氢ħ -咪唑并[1,2- f ]菲啶鎓衍生物。进行了一系列NMR相转移实验以阐明机理途径,并且该方法已经通过使用N-溴代琥珀酰亚胺作为助氧化剂的双相系统进一步发展。该方法也已扩展到其他N-杂环阳离子衍生物,例如喹啉鎓和喹唑啉鎓。
An unusual substitution reaction directed by an intramolecular re-arrangement
作者:Alexis D.C. Parenty、Louise V. Smith、Leroy Cronin
DOI:10.1016/j.tet.2005.06.074
日期:2005.8
Secondary amines and thiols undertake a substitution reaction on the side chain of 2-bromoethyl-pyridinium derivatives ' directed ' by an intramolecular re-arrangement. Experimental investigations strongly indicate that the reaction is initiated by an alpha addition of the nucleophile onto the iminium moiety of the N-heteroaromatic cation, followed by a cyclisation and in oxidative ring opening. This novel substitution process is able to occur with less reactive nucleophiles that would not undergo conventional substitution with ' isolated ' bromoethyl moieties. (c) 2005 Elsevier Ltd. All rights reserved.