Nitrogen-aryl bond, Buchwald-Hartwig

Amines are generally prepared by nucleophilic amination, which is a coupling of carbon electrophiles with a nucleophilic amination reagent, NR2, and Ni and Pd catalyzed reaction of aryl halides with arylamines (Hartwig-Buchwald amination) . Thus, the direct C—N bond formation between carbon nucleophiles and electrophilic nitrogen functionality R2N+ constitutes an example of the umpolung methodology. 

The seminal work by the groups of Hartwig and Buchwald in 1994 on aryl amina-tion chemistry has spurred substantial research on C-N bond formation in general and aryl-nitrogen bond formation in particular [114]. Catalytic aryl amine couplings are usually slow processes, especially when copper catalysis is used, often... 

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