Potassium salts, enolate derivatives arylation

Phenylmercury derivatives of 3-aminomethylene-l-methyloxindols have also been investigated (79KGS65). For studies of the effect of substituents on the electronic structure of silver and potassium salts of 3-(aryl)imi-nooxindole see 76MI2. The keto-enol and imino-enamine tautomerism of compounds of type 127 (with 128 and 129) has been investigated (85KGS921). 

A similar beneficial effect of 1,1-diphenylethylene on the yields of arylation products was later observed in the synthesis of benzonitrile derivatives by reaction of diaryliodonium salts with potassium cyanide and in the reaction of diaryliodonium salts with the sodium salt of nitroalkanes. 7 In the latter case, the reaction was therefore considered to result from intermediate inner-sphere radicals. Some years later. Barton et al. showed that 1,1-diphenylethylene acts as an efficient inhibitor of the radical chain process in the reaction of enolates with diaryliodonium salts. They concluded that the arylation products arose from a non-radical process. 

Diaryliodonium salts react more or less easily with carbonyl compounds to afford the C-arylated derivatives. Depending upon the nature of the substrate, different experimental conditions have been used. These reactions are generally performed in alcoholic solvents (r-BuOH, r-AmOH.) or in DMF, at temperatures ranging from low (- 78°C) to reflux of the solvent. Arylation of simple ketones has been obtained either by reaction of the ketone enolates with an appropriate diaryliodonium salt, i or by reaction of the ketone enol silyl ether with diaryliodonium fluoride. Phenylation of the potassium enolate of acetone (13) with diphenyliodonium bromide (14) afforded a modest yield of the monophenylation product, but the stimulation with solvated electrons led to overreaction due to the subsequent reaction of the iodobenzene, a good SrnI arylating agent under these conditions. 9... 

Indoles and Carbazoles. - Formation. 2-Arylindoles (132) are formed by intramolecular Wittig reaction of the phosphonium salts (131). The hydroxamic acids PhN(OH)COCH2COR (R = alkyl or aryl) cyclize in boiling toluene to mixtures of indoles (133) and 3-isoxazolones (134). Irradiation of a solution of o-iodoaniline and the potassium enolate of acetone affords 2-methylindole. The enamino-ketone (135) cyclizes photochemically to 1,2-dimethylindole (136) with elimination of acetaldehyde/ The styrene derivative (137), obtained by the action of Meerwein s acetal, Me2NCH(OMe)2, on o-nitrotoluene, yields 1-hydroxyindole on treatment with zinc/ Azidobenzocyclobutanes (138 R = Me, Ph, or CH2Ph) are converted into indoles (133) by the action of concentrated sulphuric acid/ ... 

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