Phosphonous dichloride, trichloromethyl

The reaction of chloromethylphosphonic dichloride with tetra-phosphorus decasulfide or with thiophosphoryl chloride are the only methods of preparation for this compound reported. The method is applicable more generally, and the syntheses of methyl-, trichloromethyl-, ethyl-, propyl-, cyclohexyl-, phenyl-, and -chlorophenylphosphonothioic dichloride from the corresponding phosphonic dichlorides have been reported. Phos-phinic chlorides of varying structures could also be converted to the corresponding thiono compounds by comparable procedures. The present method is preferable to the thiophosphoryl chloride procedure in that it does not require working under pressure. 

Yet another form of addition reaction is that of (trichloromethyl)phosphonic dichloride, as a consequence of its highly polarized C-Cl bonds, to buta-1,3-dienes in the presence of CuCl addition is 1,4, with the formation of (l,l,5-trichloropent-3-enyl)phosphonic dichlorides (139) as Z-E mixtures ". ... 

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