Amines Ullmann-Goldberg coupling

Figure 36 - Aromatic amines via the Ullmann-Goldberg coupling...

Abstract Although requiring the use of stoichiometric amounts of metal and harsh conditions, the copper-mediated coupling reactions of aryl halides with amines and phenols (Ullmann craidensatiOTis), amides and carbamates (Ullmann-Goldberg condensations), or activated methylene compounds (Ullmann-Hurtley condensations) have been for a long time useful methods for the formation of C(aryl)-N, C(aryl)-0, and C(aryl)-C bonds. In 2001, a renaissance of the Ullmann reaction has been initiated with the discovery of versatile new copper catalytic systems for C-C, C-N, or C-O coupling under mild temperature ccmditions. 

Efficient and selective coupling of aryl and vinyl halides with N, O, and C nucleophiles are indispensable and important transformations to construct useful compounds. Over 110 years ago, Ullmann and Goldberg found the synthesis of aryl ethers and aryl amines by C-N and C-O bond-forming reactions in the presence of copper powder or copper salt. However, even until the late twenty century, these transformations often required stoichiometric amounts of copper reagent in polar solvents (such as N-methylpyrrolidone, nitrobenzene, and dimethylformamide) at high reaction temperatures (>200 °C). These harsh reaction conditions frequently led to... 

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