Evidence of Reversibility in Azo-Coupling Reactions between 1,3,5-Tris(<i>N</i>,<i>N</i>-dialkylamino)benzenes and Arenediazonium Salts
作者:Carla Boga、Erminia Del Vecchio、Luciano Forlani、Silvia Tozzi
DOI:10.1021/jo071111k
日期:2007.11.1
The reactions between strongly electron-rich aromatic substrates (1,3,5-tris(N,N-dialkylamino)benzenes, neutral carbon super nucleophiles) and diazonium salts produce moderately stable σ complexes (Wheland complexes). The reactivity of Wheland complexes with electrophiles (other diazonium salts, or 4,7-dinitrobenzofuroxan) produces exchange reactions in the electrophilic part: the better electrophile
强电子富集的芳香族底物(1,3,5-tris(N,N-二烷基氨基)苯,中性碳超级亲核试剂和重氮盐可产生中等稳定的σ配合物(Wheland配合物)。Wheland配合物与亲电试剂(其他重氮盐或4,7-二硝基苯并呋喃恶烷)的反应性在亲电部件中产生交换反应:亲电试剂越好,取代的亲电试剂越弱。同样,在Wheland与1,3,5-三(吗啉基)苯的配合物中,1,3,5-三(哌啶基)苯取代了功能较弱的亲核试剂1,3,5-三(吗啉基)苯。此处报道的证据表明,对于标题系统,产生亲电子试剂的Wheland配合物的攻击反应是可逆的过程。重氮偶联反应的最终产物受到一些重氮盐的进一步侵蚀。