Ullmann condensation

Illustrative of the traditional Ullmann ether synthesis is the preparation of p-nitrophenyl phenyl ether from 4-chloronitrobenzene and phenol. : Copper is used as a catalyst, either in the form of the metal or copper salts. Modern arylations use soluble copper catalysts. ==Goldberg reaction: C-N coupling==

A traditional Goldberg reaction involves reaction of an aniline with an aryl halide. The coupling of 2-chlorobenzoic acid and aniline is illustrative: : A typical catalyst is formed from copper(I) iodide and phenanthroline. The reaction is an alternative to the Buchwald–Hartwig amination reaction. Aryl iodides are more reactive arylating agents than are aryl chlorides, following the usual pattern. Electron-withdrawing groups on the aryl halide also accelerate the coupling. ==Hurtley reaction: C-C coupling==

The nucleophile can also be carbon including carbanions as well as cyanide. In the traditional Hurtley reaction, the carbon nucleophiles were derived from malonic ester and other dicarbonyl compounds: ==C–S coupling==

The arylation of alkylthiolates proceeds by the intermediacy of cuprous thiolates.{{cite journal|title=1,2-Bis(N-butylthio)benzene|author=Roger Adams, Walter Reifschneider, Aldo Ferretti ==Mechanism of Ullmann-type reactions==

In the case of Ullmann-type reactions (aminations, etherifications, etc. of aryl halides), the conversions involve copper(I) alkoxide, copper(I) amides, copper(I) thiolates. The copper(I) reagent can be generated in situ from the aryl halide and copper metal. Even copper(II) sources are effective under some circumstances. A number of innovations have been developed with regard to copper reagents. :{{chem2|ROCuAr(X)L_{n} → RO\sAr + CuL_{n}|}} ==History==

The Ullmann ether synthesis is named after its inventor, Fritz Ullmann. The corresponding Goldberg reaction, is named after Irma Goldberg. The Hurtley reaction, which involves C-C bond formation, is similarly named after its inventor. ==References==