Carbon tetrachloride, reaction with thiophenol

The chemistry of 149 is rather unusual from the point of view of the typical reactivity pattern observed for ordinary small-ring systems. Especially striking is the ease of central bond opening in radical reactions. Thus 149 spontaneously reacts with iodine, thiophenol, and even with carbon tetrachloride to give almost quantitative yields of the respective 1,3-adducts 153a-c (Scheme 4.51). A number of other additions, including those leading to the formation... 

A novel reaction leading to aryloxy- or arylthio-phosphonium salts involves treating a phosphine in the series Phn (Me2N)3, P, where n =0—3, with a phenol or thiophenol and carbon tetrachloride.249 The products, [Phn(Me2N)3 P(OAr)]+, can then be isolated as the hexachloroantimonates. 

Regioselective displacement of chlorine from 4,5-dichloro-3(2//)-pyridazinones has been shown to be exceptionally dependent on the solvent and has been the subject of several studies. With 2-methyl and 2-phenyl-4,5-dichloro-3(2//)-pyridazinones as substrates, reaction with alkoxides occurs selectively at C-4 in less polar solvents (carbon tetrachloride, dioxane, THF, t-BuOH, pyridine), is nonselective in solvents of intermediate polarity (acetone, 2-propanol), and is selective for C-5 in polar solvents (EtOH, MeOH, DMF, DMSO) with the exception of acetonitrile, in which mixtures are obtained. Similar selectivity was seen with phenol and ethanethiol, but with thiophenol and ethyl... 

Aryl alky ethers. The reaction of an alcohol with hexamethylphosphorous triamide in carbon tetrachloride at low temperatures results in formation of an alkoxytris(dimethylamino)phosphonium chloride (1), which can be converted into the stable hexafluorophosphate (2) by addition of ammonium hexafluoro-phosphate. The salt (2) reacts with potassium phenolates or aryl thiophenolates... 

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