Substitution reactions Ullman reaction

The Ullman reaction has long been known as a method for the synthesis of aromatic ethers by the reaction of a phenol with an aromatic halide in the presence of a copper compound as a catalyst. It is a variation on the nucleophilic substitution reaction since a phenolic salt reacts with the halide. Nonactivated aromatic halides can be used in the synthesis of poly(arylene edier)s, dius providing a way of obtaining structures not available by the conventional nucleophilic route. The ease of halogen displacement was found to be the reverse of that observed for activated nucleophilic substitution reaction, that is, I > Br > Cl F. The polymerizations are conducted in benzophenone with a cuprous chloride-pyridine complex as a catalyst. Bromine compounds are the favored reactants.53,124 127 Poly(arylene ether)s have been prepared by Ullman coupling of bisphenols and... 

Apart from nucleophilic substitution reactions, the chemistry of the halo derivatives of the 7r-deficient heterocycles is fairly similar to that of aromatic halides. Thus, heterobiaryls can be prepared by the Ullman reaction, and Grignard reagents and organolithium compounds can be prepared, although in many instances, and especially with Grignard reagents,... 

Poly(phenylene ether) s with pendant perfluoroalkyl sulfonic acids with an ion exchange capacity of 1.17-1.83 equivalents/g have been synthesized by an aromatic nucleophilic substitution reaction of a perfluo-romonomer, such as decafluorobiphenyl or hexafluo-robenzene with 2,5-bis(4 -iodophenyl)hydroquinone, followed by a Ullman coupling reaction with potassium 1,1,2,2-tetrafluoro-2-(l, 1,2,2-tetrafluoro-2-iodoethoxy)ethanesulfonate [100]. 

Yet another approach to these compounds consists of substituting the piperazine ring onto the preformed heterocyclic moiety. Ullman condensation of the substituted thiosalyciclic acid (40-1) with ort/zo-chloronitrobenzene results in the displacement of chlorine by thiophenoxide and the formation of the thioether (40-2). The nitro group in this last intermediate is then reduced to an aniline (40-3) the resulting amino acid is then cyclized thermally to the lactam (40-4). Treatment of that with phosphorus oxychloride gives the imino chloride (40-5). Reaction with N-methylpiperazine leads to the replacement of chlorine by nitrogen and the formation of clothiapine (40-6) [39]. 

The prevalence of the aniline functional group in alkaloid natural products of medicinal interest has inspired a number of metal-catalyzed strategies for the preparation of substituted anilines. One classical method, a variation of the Ullman aryl ether synthesis, features copper catalysis. This method generally suffers from harsh reaction conditions and limited substrate scope. Nonetheless, the simplicity of the transformation and the inexpensiveness of copper catalysis has prompted additional development of this strategy. For instance, cyclohexylphenylamine is formed in excellent yield from the copper(I) iodide-catalyzed amination of iodobenzene. ... 

It is also known that carbon dioxide is an effective cocatalyst in Ullman-t) e methanolysis of aryl halides.Vinylsilanes can also be prepared through the reaction of polyhalides with a-halogen-substituted allylsilanes using CuCl. The coupling of... 

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