Microwave-Assisted Efficient Copper-Promoted N-Arylation of Amines with Arylboronic Acids

摘要

Amination of arylboronic acids is one of the most important reactions in the synthesis of essential intermediates and targets of numerous pharmaceutical agents,agrochemi-cals,natural products,and industrial materials containing the N-aryl moiety.One of the traditional methods to create the C-N bond is the transition-metal-catalyzed arylation of nucleophiles with aryl halides,that is,the Ullmann or Goldberg condensations.2 Recently,significant progress has been achieved in C-N bond formation;for example,Ullmann coupling has led to the emergence of several protocols based on copper or iron-copper catalysis.Chan and Lam4 reported the preparation of C-N bonds via Cu-mediated coupling of amines with arylboronic acids under milder conditions,where arylboronic acids are used as arylating agents instead of aryl halides.5 Although these methods are highly effective,there is still much room for improvement,for example,these methods usually require high temperatures,long reaction times,and complex ligands,and some of them suffer from a relatively narrow scope of substrates,especially for aniline derivatives.