Trifluoromethylphosphonic

Trifluoromethylphosphonous bistriazolide (trifluoromethylbistriazolylphosphine) has been employed in the synthesis of trifluoromethylphosphonate analogues of nucleotides. 071... 

Dinucleoside phosphorofluoridites are readily available (Example 47). The Me3SiCF3 reagent reacts with this type of compounds in the presence of a catalytic amount of CsF (step a) and the trifluoromethylphosphonite formed was oxidized to trifluoromethylphosphonate by TBHP (step b). The method is particularly valuable as it is compatible with a sequential procedure combining the formation of phosphorus-fluorine compounds from pi haryloxy precursors with the reaction leading to P cp groups. Both reactions require the presence of fluorine ions as a substrate or catalyst. 

Because of the high volatility of the trifluoromethyl halides and their inertness in the thermal Michaelis-Arbuzov reaction,2 the synthesis of diethyl trifluoromethylphosphonate under pho-tolytic conditions has been investigated. The modest yield initially obtained (51%) can be improved using vacuum Une techniques, and the desired trifluoromethylphosphonate is isolated in almost quantitative yield (Scheme 3.45). ... 

Finally, to conclude this chapter, passing reference may be made to certain perfluoro derivatives of organo-phosphorus compounds that have recently been prepared. The starting point is trifluoroiodomethane, CF3I, prepared from trifluoro-acetic acid and iodine. The interaction of phosphorus and trifluoroiodomethane at about 200° gives P(CF3)3, P(CF3)2l and P(CF3)l2. The first of these compounds is a spontaneously inflammable liquid which reacts smoothly at —40° to give (CF3)gPCl2 in quantitative yield. When P(CF3)l2 is oxidatively hydrolysed trifluoromethylphosphonic acid, CF3-PO(OH)2, is obtained ... 

The analogues adenosine 5 -0-trifluoromethylphosphonate (72) and 2 -0-deoxythymidine 3 -0-trifluoromethylphosphonate have been prepared from the bis-triazolide of trifluoromethylphosphinic acid which was obtained from trifluoromethylphosphorus dibromide. 

Trifluoromethylphosphonous acid is obtained by hydrolysis of the halophosphine, but its sodium salt is sodium trifluoromethyl phosphinate. 

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