以氨为氮源的C-N偶联反应研究进展

摘要

C-N偶联反应是合成芳香胺的重要手段,咪唑、脂肪胺和氨常用作该反应的氮源.氨是最简单的氮化合物,应用在该反应中不仅廉价而且更加绿色环保.然而,由于氨结构以及偶联后产物结构使其存在一定的挑战性.各种催化体系的出现实现了以氨为氮源的C-N偶联反应.综述钯和镍在均相、多相体系中催化氨为氮源的C-N偶联合成苯胺类化合物的反应.这类金属催化剂催化活性较高,但存在进一步偶联生成二级胺的问题,且催化剂成本偏高.铜作为廉价金属在C-N偶联反应中的应用一直受到关注,重点介绍各种常见的铜盐、铜纳米材料和负载型铜催化剂等在氨为氮源的C-N偶联反应中的应用.%C-N coupling reaction is an important route for synthesis of aromatic amines.Imidazoles,aliphatic amines and ammonia are usually used as nitrogen sources for the coupling.As the simplest nitrogen compounds,ammonia is of low cost and environmentally-benign for this reaction.But due to the structure of ammonia and the resultant coupling product,using ammonia as nitrogen source is of challenge.Emerging of various catalytic systems makes it feasible C-N coupling reaction using ammonia as nitrogen source.The researches on C-N coupling reaction catalyzed by palladium,nickel and copper in homogeneous and heterogeneous phase,using ammonia as nitrogen source,were reviewed in this paper.These catalytic systems exhibit high catalytic activity,but some systems result in further coupling to form secondary amines byproducts,such as diphenylamines or triphenylamines,and palladium and nickel catalysts are of high cost.As an inexpensive metal,use of copper catalyst in C-N coupling reaction attracts much attention.Application of copper salts,nanoparticle copper and supported copper as the catalysts for C-N reaction using ammonia as nitrogen source was reviewed in detail.