A. Yu. Volkonskii

Perfluorocarboxylic acid anhydrides and halides in the Wittig reaction

Conclusions1.Perfluorocarboxylic acid anhydrides and halides undergo the Wittig reaction with stable phosphorus ylides that do not contain anα-hydrogen atom.2.In contrast to other carbonyl compounds, perfluorocarboxylic acid anhydrides and halides undergo the Wittig reaction with hexafluoroisopropylidenetriethoxyphosphorane.

X-ray structure study of 2,2,4,4,6,6,8,8,10,10-decakis(trifluoromethyl)-1,3,5,7,9-pentamercuriacyclodecane [(CF3)2CHg]5·2C5H5N·2H2O

Conclusions1.A complete x-ray structure study was made of 2,2,4,4,6,6,8,8,10,10-decakis(trifluoromethyl)-1,3,5,7,9-pentamercuriacyclodecane.2.In the cyclic oligomer the 10-membered Hg5C5 ring has a practically planar structure, and the presence of a large number of trifluoromethyl substituents has little effect on the geometric parameters of the molecule.

Mixed anhydrides of α-mercuriohexafluoroisobutyric acids

Conclusions1.Mercury salts of carboxylic acids are readily added on to bis(trifluoromethyl) ketene and its N-phenylimine, forming mixed anhydrides or imides of α-mercuriobishexafluoroisobutyric acid.2.The mixed anhydride of trifluoroacetic and α-mercuriobishexafluoroisobutyric acids is readily decomposed to bis(trifluoromethyl) ketene, trifluoroacetic anhydride, and the internal salt of α-mercuriohexafluoroisobutyric acid. On decarboxylation in pyridine this salt is converted to hexafluoroisopropylidenemercury.

E,Z-Isomers of 3-ethoxy-4,4,4-trifluorobut-2-enenitrile and N-methylpyrrolidines derived from them

Abstract3-Ethoxy-4,4,4-trifluorobut-2-enenitrile was synthesized by the Wittig reaction of ethyl trifluoroacetate and (cyanomethylidene)triphenylphosphorane and was separated to individual E- and Z-isomers by rectification. Each isomer undergoes stereospecific 1,3-dipolar cycloaddition to N-methyl(methaniminio)-N-methylide generated in situ to give E- and Z-isomers of 4-cyano-3-ethoxy-3-trifluoromethyl-1-methylpyrrolidine.

Mechanism of the cleavage of mixed anhydrides of α-hydrohexafluoroisobutyric acid by triethylamine

Conclusions1.Reaction of triethylamine with the mixed anhydride of α-hydrohexafluoroisobutyric and benzoic acids results in cleavage of an α-proton to form a salt containing a mesomeric carbanion which is stable at temperatures below −40°C.2.Cleavage of the triethylammonium salt of the mixed anhydride of α-hydrohexafluoroisobutyric and benzoic acids to benzoyl fluoride and a salt of trifluoromethylmalonyl difluoride involves several reversible elimination-addition steps of fluoride and triethylammonium benzoate, together with irreversible cleavage of the acid fluoride and mixed anhydride of α-hydro-β-benzoyloxypentafluoroisobutyric acid.3.According to the19F NMR spectrum, the triethylammonium salt of trifluoromethylmalonyl difluoride at temperatures below −50°C contains three isomers as a result of restricted rotation around the partial double bonds in the mesomeric carbanion.

An unusual cleavage of mixed anhydrides of α-hydrohexafluoroisobutyric acid by the action of tertiary amines

1. The anhydride and mixed anhydrides of α-hydrohexafluoroisobutyric acid (CF3)2CHCOOCOR decompose upon reaction with a tertiary amine with the formation of the acid fluoride RCOF and adduct of the diacid fluoride of trifluoromethylmalonic acid with the tertiary amine. 2. The N-phenyl-N-benzoylamide of α-hydrohexafluoroisobutyric acid is decomposed by triethylamine with the formation of N-phenylbenzimidoyl fluoride and the adduct of the diacid fluoride of trifluoromethylmalonic acid with triethylamine. 3. New methods were found for the preparation of the diacid fluoride of trifluoromalonic acid.