Chloromethyl tetrafluorophosphorane

The reaction is conducted in a 50-ml. three-necked flask equipped with an efficient reflux condenser, topped by a drying tube, a thermometer, and a 30-ml. dropping funnel. The ground joints are greased with Fluorolube GR 660 stopcock grease (checkers found Kel-F to be adequate). The system is carefully evacuated and filled with dry nitro- 

Dimethyltrifluorophosphorane was first obtained by the fluorination of dimethylchlorophosphine with antimony- 

The reaction mixture is slowly heated. Between 80 and 100° inner temperature a liquid product starts to distill. The colorless reaction mixture gradually turns dark black. Distillation is continued until the pot temperature reaches 250°. Material distilling between 60 and 75° (mainly 60 to 65°) is collected. The yield is 35 to 38 g. (74 to 81%). The product is redistilled over a small amount of sodium fluoride through a 10-in. glass helix-packed column in a nitrogen atmosphere at atmospheric pressure b.p. 61 to 62°. (The checkers, working on half this scale report a yield of 76%, b.p. 61 to 62°.) Dimethyltrifluorophosphorane may be stored in a Teflon or stainless-steel container. 

Dimethyltrifluorophosphorane is a liquid of b.p. 61 to 62° which must be handled with careful exclusion of moisture. 

3(C6H6)2PC1 4- SAsFa- 3(C6H6)sPF3 -h 2As 4- AsCb 

---

Chloromethyl)tetrafluorophosphorane has been obtained thus far only by the above reaction. It may be noted that, although a redox reaction takes place between (chloro-methyl)dichlorophosphine and antimony (III) fluoride, (chloromethyl)difluorophosphine is the only product formed. The reaction of dichlorophosphines with anti-mony(V) fluoride was the first method of preparation of tetrafluorophosphoranes to be reported. The strongly oxidizing antimony(V) fluoride, however, seems to be required only in special instances, such as the one described below. 

Benzylic Reactivity. 2,5-Dimethyl-3,4-dinitrothiophen has been condensed with aromatic aldehydes to give 3,4-dinitro-2,5-distyryl-thiophens. " An improved synthesis of 3-nitro-2-styryl-thiophens involves bromination of 3-methyl-2-nitrothiophen with A-bromosuccinimide, followed by a modified Wit-tig reaction. From 2,5-di(chloromethyl)thiophen, the phosphonate was prepared by the Arbusov reaction, which was used for the preparation of 2,5-distyryl-thiophens. Trichloromethyl(thienyl)carbinols have been converted into the corresponding fluoro-derivatives through the reaction with phenyl-tetrafluorophosphorane. The liquid-phase catalytic oxidation of phenyl-(2-thienyl)methane in acetic acid in the presence of cobalt(ll) acetate and sodium bromide has been investigated. ... 

---