1,1,2,2-Tetrafluoro-3- -propane

Sulfonyl Fluoride 2-Oxo-1,3,3.3-tetrafluoro-propane ElOb, 212 (Educt)... 

NsCFjCFX N,CF,-CFXI + N,- 4-Diazo-l,l,l,2,2,3,3-heptafluoropentane and 3-diazo-l,l,2,2-tetrafluoro-propane have bem successfully prepared by the routes n-CjFv-COMe... 

This would have results in 77 hits from l,2-[propadiene, 1,1,2,2-tetrafluoro-] with a boiling point of —38 °C, to [propane, l,l,l,2,3,3,3-heptafluoro-2-(trifluoromethyl)-] with a boiling point of 0 °C. Out of 77 hits, 49 of them contain elements that include B, Si, N, P, As, O, S, Cl, Br, and I, and perhaps too toxic to be considered as refrigerants seriously. There are 11 hits that are hydrocarbons, such as butane, which would be too flammable to be considered. Perhaps we would eliminate the six hits that have double or triple bonds, as they tend to be less stable and could polymerize. The remaining ones are all hydrofluorocarbons (HECs) without chlorine, and the prime candidates are C2H2E4, C3H3E5, and C4F10. 

The products from the partial fluorinations of butane32 and 2-methylpropane33 over cobalt(lll) fluoride are even more complex, 51 and 27 compounds, respectively, being identified. Most are C4F H10 n isomers which retained the original carbon skeletons, but up to 2% in each case has the carbon skeleton of the isomer (i.e., 2-methylpropane fluorination yields ca. 2% of products with the butane skeleton). From butane, at 140-230 C, only two compounds are present as more than 10% of the reaction product, 1 //,3//-octafluorobutane (11%) and 1 //,27f,4//-heptafluorobutane (14%). 2-Methylpropane is similar, at 140- 200°C only four compounds are present as over 10% of the product 2-(difluoromethyl)-l,1,1,2,3-pentafluoro-propane (14%), 2-(difluoromethyl)-l,l,2,3,3-pentafluoropropane (16%), 1,1,2,3,3-pentafluo-ro-2-(fluoromethyl)propane (24%), and l,l,2,3-tetrafluoro-2-(fluoromethyl)propane (15%). 

The action of sodium methoxide or potassium hydroxide on 2,3,3,3-tetrafluoro-l-(2-hy-droxyphenyl)propan-l-one (34) gives 3-fluoro-4-hydroxy-27/-chromen-2-one (35).139... 

To a solution of l,l,2,2-tetrafluoro-3-(tosyloxy)propane (0.86 g, 3 mmol) in THF was added dropwise 1.6M BuLi in hexane (4.1 mL, 6.6 mmol) at — 78°C over 20 min under argon. After lOmin at — 78 "C, the reaction was quenched with cold 10% aq HC1. Extraction, drying, concentration, and column chromatography (benzene) give a pale-yellow syrup yield (70%) (E/Z) 14 86. The procedure can also be applied to a 15-mmol scale. 

Acidic hydrolysis of pentafluoro-l-(2-methoxyphenyl)prop-l-ene gives 2,3,3,3-tetrafluoro-l-(2-methoxyphenyl)propan-l-one (8) by hydrolysis of the vinylic fluorine concomitant cleavage of the ether group produces the corresponding phenol 9 in variable amounts, depending on the reaction conditions.15... 

With perfluorobenzoic acid, the attempted replacement of one fluorine by methanethiol in the ethylene glycol/pyridine system resulted in a 60% yield of a 4-methylsulfanyl-substituted product in which the carboxy group is replaced by hydrogen.38 However, in methanol (16 h reflux, with NaOMe). tetrafluoro-4-(mcthylsulfanyl)benzoic acid was obtained in 83% yield,43 and in refluxing propan-2-ol, tetrafluoro-4-(methylsulfanyl)benzenemethanol was obtained in 73% yield.44... 

Propane 1,3-Dichloro-2-(2.2-dtmethyl-propanoylamino)-2-hydroxv-tetrafluoro- EI4a/2, 57/ 63(R,CO + R-CO-NH2)... 

Propane 1-Cyclopentyl-1.1.2.2-tetrafluoro- ElOa. 340 (2 CO 2CF2) c8h)2f4n2... 

Propane 2-(Heptafluoro-propyloxy)-hexafluoro-1-(1-iodo-tetrafluoro-ethoxy)- ElOa, 403 (Educt)... 

Propane 1-(2-IIydroxy-phenyl)-1-oxo-tetrafluoro-2I I- E10b2, 383 (En —F —, CO —CH/OCH3 OH)... 

Propane I 2-Dichlmo-2-(4-methoxy-phcnyl)-tetrafluoro E 0b2. 144 (Educt)... 

Propane l,3-Dichloro-2-hydroxy-1.1.3.3-tetrafluoro-2-(4-methyl-benzenesulfinylamino)- E14a/2,... 

Propane 2-(3.5-Dimcthyl-4-hydroxy-phcnyl)-tetrafluoro-1,2,3-trichlo-ro- E10b2. Ill (Educt)... 

Propane 2-[2-(Heptafluoro-piopyl-oxy)-hexafluoro-propyloxy]-hexafluoro-1 -(tetrafluoro-1 -... 

Jiang has expanded the Carreira method of alkyne addition to aldehydes to include other ligands and Zn(II) salts (Eq. 13) [17]. Thus use of stoichiometric quantities of Zn(II) difluoromethane sulfonate salt and (lS,2S)-3-(tert-butyldi-methylsilyloxy)-2-N,N-dimethylamino-l-(p-nitrophenyl)propane-l-ol (3) in the addition reaction can afford propargylic alcohols in high ee. Difluoromethanesul-fonic acid is prepared from 3,3,4-,4-tetrafluoro[1.2]oxathietane the amino alcohol has been used in the synthesis of chloramphenicol and is also readily accessible. Application of a combination of this same amino alcohol ligand with Zn(OTf)2 has also been shown to afford products in high yield and ee in addition reactions (Eq. 14) [18]. 

Tetrafluoro-l-(trifluoromethyl)propan-l-imine (29) Typical Procedure ... 

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