Yu. V. Zeifman

Dehydrofluorination with triethylamine-boron trifluoride adduct. New synthesis of perfluoromethacrylic acid derivatives and related compounds

Abstract Adduct (C2H5)3N·BF3 has proved to be a suitable dehydrofluorinating reagent for preparing highly reactive fluoroolefines through dehydrofluorination of corresponding monohydro derivatives. Its advantage over other dehydrofluorinating agents are demonstrated by the synthesis of a number of perfluoromethacrylic acid derivatives.

Fluorine-containing heterocumulenes Communication 5. A new synthesis of bis(trifluoromethyl)ketenimines

1. Methods were developed for the synthesis of bis(trifluoromethyl)ketenimines by the reaction of perfluoroisobutylene with primary amines, or by the dehydrofluorination of the imidoyl fluorides ofα-hydroperfluoroisobutyric acid. 2. The perfluoroisobutylene-triethylamine mixture is a mild dehydrofluorinating agent.

Fluoro-containing heterocumulenes

1. Bis (trifluoromethyl)ketene reacts with diazomethane and with isonitriles at its carbonyl group to give 1,3 -dioxolanes. 2. The reaction of diazomethane with the β-lactone dimer of bis(trifluoromethyl)ketene was studied.

Fluorinated diiodoalkanes and diolefins

1. Higherα,ω-diiodoperfluoroalkanes, I(CF2)nI, n=2, 4, 6. 2. The addition of ethylene toα, ω-diiodoperfluoroalkanes was accomplished. 3. α,ω-Divinylperfluoroalkanes capable of polymerization were obtained.

Reaction of vicinal dihalopolyfluoroalkanes with sodium azide

Conclusions1.The reaction of vicinal dihalopolyfluoroalkanes and related compounds with sodium azide causes replacement of halogen by an azide group, probably by an ionic cleavageaddition chain mechanism.2.Nucleophilic azidobromination of fluoroolefins has been carried out by the action of sodium azide and bromine.3.These reactions were used to synthesize new β-halopolyfluoroalkyl azides.

Synthesis of allenes containing geminal trifluoromethyl groups

Abstract Allenes (CF 3 ) 2 CCC(COOMe) 2 and (CF 3 ) 2 CCC(COOEt) Ph were prepared by Cs-catalyzed condensation of octafluoroisobutene with dimethyl malonate and ethyl phenylacetate respectively. A stable salt is formed from (CF 3 ) 2 CCC(COOMe) 2 and CsF. Similar salts were prepared through the condensation of octafluoroisobutene with ethyl cyanoacetate and malononitrile. Allenes (CF 3 ) 2 CCOMe 2 and (CF 3 ) 2 CCCHPh were synthesized by dehydrofluorination of olefines (CF 3 ) 2 CHCFCRR′ under the action of octafluoroisobutene and CsF mixture; the latter allene has been isolated only as a cycloadduct with octafluoroisobutene.

Generation of radicals by the photolysis of branched fluoroolefins and their study by EPR spectroscopy

The UV irradiation of branched fluoroolefins leads to the formation of free radicals due to the addition of CF3 to the starting olefin. Branched fluoroolefins containing a fluorine atom at the radical site are incapable of recombination but react with oxygen.

S-anions from 2,2,4,4-tetrakis(Trifluoromethyl)-1,3-dithietane and their reactions

Conclusions1.The system containing 2,2,4,4-tetrakis (trifluoromethyl)-1,3-dithietane and halide ion is the equivalent of the α-halohexaf luoroisopropylthio anion and may be used in the synthesis of compounds containing α-fluoro and α-chlorohexafluoroisopropylthio groups.2.The cycloadduct of perfluoroisobutylene and hexafluorothioacetone was obtained under nucleophilic catalysis conditions.

Organometallic synthesis of compounds containing a perfluoroisobutenyl group

ConclusionsPerfluoroisobutenyllithium and perfluoroisobutenylmagnesium bromide were obtained, and it was shown that these reagents can be used in the synthesis of compounds containing a perfluoroisobutenyl group.

Fluorine-containing imines. 1. New cycloaddition reactions of acylimines of fluoroketones

ConclusionsAcylimines of fluoroketones react with nitriles and aromatic aldehydes to form 1,4-cycloadducts, and with difluorocarbene give 1,2- and 1,4-cycloadducts, with the latter predominating.