Thiophosphinic acid halides

The alkylation, with the more reactive of alkyl halides, of the sodium salts of monoes-terified phosphonothioic acids (equation 22) (see also Scheme 11) or of the disodium salts 107 results in preferential S-alkylation, and the same situation obtains for the salts of phosphinothioic acid " methylation can also be carried out with dimethyl sulphate. Alkylations may also be performed under phase-transfer conditions. From both practical and theoretical perspectives, the subject is more complex, since the course of alkylation reactions depends on the nature of the alkylating agent, on the polarity of solvent and whether this is protic or non-protic and on the concentrations of reactants a study of these features has been the subject of two reports In non-polar or weakly polar aprotic media, or in EtOH, alkylation occurs almost exclusively on sulphur, but in dipolar aprotic solvents, O-alkylation also takes place. The relative yields of sulphur- and oxygen-substituted derivatives, [Qs/Qol depends, for a given solvent, on the nature of substituents on phosphorus, i.e. essentially, whether the substrate is a thiophosphoric, thiophosphonic or thiophosphinic acid. With alkyl tosylates as alkylating agents at 0.02 m in hmpt, the alkylation of sodium 0,0-dialkyl or diphenyl phosphorothioates results in 100% overall conversions with [Qs/Qo] 5 the overall yields for sodium diphenyl- or diisopropyl-phosphinothioates are lower (50-100%) with [Qs/Qo] 1 ... 

CsFs-PRX (X = Br or Cl). The fluorides CeFs PRF are formed when the last compounds are treated with sodium fluoride in acetonitrile, and the phosphorancs CeFs-PRFs are obtained from the diethylamino-compounds (CeFs-PR-NEta) and arsenic trifluoride the phosphoranes react with hexamethyldisiloxane to give phosphinic acid fluorides, C6F5 P(O)RF.4 0 Preparation of the thiophosphinic halides C6F5-P(S)RX (X = Br, Cl, or F R = Me, Et, Bu. Ph, or CeFs) and of the thiophosphonic halides (C0Fs)2P(S)X has also been described, and their tP and n.m.r. spectra have been discussed.The hydrido(pentafluorophenyl)phosphate (250), obtained from dibromo(pentafluorophenyl)phosphine (Scheme 57), decomposes as shown at 50 °C. ... 

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