Ullmann-Goldberg condensation

It is worth noting that the Ullmann-Goldberg condensation of aryl halides with phenols and anilines worked efficiently in the presence of copper in water.50 For example, the coupling of 2-chlorobenzoic acid with 4-chlorophenol (K2C03/pyridine/copper powder) gave 2-(4-chlorophenoxy)carboxylic acid (Eq. 6.23).51 The Cu(I)-catalyzed transformation of 2-bromobenzoic acid into salicylic acid has also been studied in aqueous media (Eq. 6.24).52... 

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. 

Ugi condensation, asym. 43, 700 Ullmann-Goldberg reaction, modified 44,391... 

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