Alkyl-polyfluoroalkyl-phosphines

They are pungent liquids which ignite in air, undergo the expected P—Rp bond cleavage with quantitative formation of fluorocarbon hydride RpH when heated with aqueous alkali, combine readily with chlorine to give the phosphorus(v) compounds RfRPCIs, and are converted into aminophos- 

The chlorophosphine CFj(Me)PCl has been converted into dimethyltri-fluoromethylphosphine oxide (36) and the unexpectedly stable methyltri-fluoromethylphosphine oxide (37)  

The phosphine sulphide (CF3)(Me)HPS can be generated via treatment of thiobis(methyltrifluoromethyl)phosphine (40) or methyltrifluoromethyl-chlorophosphine with hydrogen sulphide but has so far evaded isolation since it equilibrates with (40) and HjS, and also slowly decomposes to yield methyltrifluoromethylphosphine and unidentified material. Methoxymethyltrifluoromethylphosphine, CF3(Me)P O Me, appears to form a stable 1 1 adduct with boron trifluoride (the position of attachment, i.e. to O or P, of the Lewis acid is unknown) and possibly an unstable 1 2 adduct. 

Work on this system provided small amounts of the new fluorophosphine CFs(Me)PF, which can be prepared in 30% yield by treatment of its chloro-analogue CFg(Me)PCl with zinc fluoiide at 25 Dimethyl- and bistrifluoromethyl-phosphines have been shown to react smoothly with olefins under u.v. radiation to give high yields of teitiary phosphines, RJPR (R = CFg, R = Et, Pr , Bu , CHMeEt, or CHFj-CFg  

The alkylbistrifluoromethylphosphines yield fluoroform essentially quantitatively when treated with a mixture of 40% aqueous sodium hydroxide and dioxan at 80 C, but the dimethyipolyfluoroethylphosphines resist such cleavage e.g. CHFjCFaPMea is only 5% converted into 1,1,2,2-tetra-fluoroethane after 6 h at 90 °C). 

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Mixed Alkyl-polyfluoroalkyl-phosphines. Chlorophosphines of the type RpRPCl (Rp = CFs or n-CjF, R = Me or CFj-CHa CHa) have been synthesized from the corresponding perhuoroalkyldihalogenophosphines CF,-Paj and n-CsF,- ... 

The use of trichloroacetaldehyde is also to be particularly noted. Although reactions between this aldehyde and various dialkyl hydrogenphosphonates have been report- 269,274,294,295 it is the dimethyl ester of (l-hydroxy-2,2,2-trichloroethyl)phosphonic acid which has received particular attention, and which has been studied widely from the structural point of view in the light of its commercial importance as the powerful insecticide dipterex (also known as trichlorphon and chlorophos). Polyfluoroalkyl esters of the related alkyl(l-hydroxy-2,2,2-trichloroethyl)phosphinic acids have been prepared by the unusual combination of chloral hydrate and the bis(polyfluoroalkyl) alkylphosphonite ester ... 

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