Julian F. S. Vaughan

'NAKED FLUORIDE ION' FROM ELEMENTAL FLUORINE

Abstract Tetrakis(dimethylamino)ethene 1 reacts with elemental fluorine to give a salt 3, which contains anhydrous fluoride ion as indicated by the 19 F NMR chemical shift.

Fluorinated di-enes

Abstract Fluorinated di-enes may be obtained by the defluorination of some oligomers of F -alkenes and -cycloalkenes using tetrakis(dimethylamino)ethene. These di-enes are very susceptible to nucleophilic attack. Nucleophilic epoxidation of ( 4 ) gives a new diepoxide which undergoes a novel ring-opening reaction. Di-ene ( 4 ) forms cyclopentadienylide derivatives with di-functional carbon nucleophiles and a cyclopentadienylide salt ( 17 ) is obtained in a remarkable ‘one-pot’ reaction from hexachlorobutadiene.

Alkylation and decarboxylation of ethyl 2-fluoro-3-oxobutanoate as a route to functionalised α-fluoro-ketones

Abstract Alkylation and decarboxylation of α-fluoro-β-ketoesters such as ethyl 2-fluoro-3-oxobutanoate offers a versatile route to a range of fluoro-ketoalkenes, demonstrating the synthetic utility of using α-fluoro-β-ketoesters as synthons for the preparation of synthetically more sophisticated selectively fluorinated systems.

Elemental fluorine. Part 7. New oxidation methodology

Abstract Reaction of fluorine with water in the presence of acids provides new oxidants for ‘in-situ’ oxidation of ketones. Direct reaction of fluorine with anhydrous alcohols and 1,2-diols provides simple methodology for oxidation to corresponding secondary ketones or α-hydroxy ketones.

Reactions involving fluoride ion. Part 39. Reactions of perfluorinated dienes with oxygen and sulphur nucleophiles

The order of reactivity of perfluorinated dienes towards methanol is 3 > 21 and the process is activated by release of angle strain. The diene 1 is hydrolysed to give perfluorotetramethyl-furan and the corresponding thiophene, is obtained by an analogous process using K2S. Hydrolysis of compounds 2 and 3 yields diketones that are strong acids. Reactions of phenols and thiophenols with 1 give aryl ethers and sulfides and difunctional nucleophiles react with 1 to give potential polymer precursors.

SYNTHESES OF PERFLUORINATED EPOXIDES, DIEPOXIDES, AND A NOVEL REARRANGEMENT

Abstractt-Butylhydroperoxide/butyl-lithium is a good reagent for synthesis of epoxides and diepoxides from polyfluorinated-alkenes and-polyenes. This reagent and calcium hypochlorite both give a novel diepoxide 5 from perfluoro-3,4-dimethyl-2,4-diene 1; diepoxide 5 undergoes a novel rearrangement, at 200°C, to the corresponding 1,4-dioxine derivative 18. Possible mechanisms are discussed.

AN INTERMOLECULAR MIGRATION OF TRIFLUOROMETHYL ANION

Abstract A fluoride-ion-induced rearrangement of a perfluorinated alkene perfluoro-4,4-dimethylpent-2-ene proceeds by migration of trifluoromethyl, giving perfluoro-2,4-dimethylpent-2-ene. It has been demonstrated that this rearrangement involves intermolecular transfer of trifluoromethyl as an anion

Direct syntheses of pentakis(trifluoromethyl)cyclopentadienide salts and related dienes

Direct routes for the synthesis of pentakis(trifluoromethyl)cyclopentadienide salts, hexakis(trifluoromethyl)cyclopentadiene and 5H pentakis(trifluoromethyl)cyclopentadiene are described.

Reactions involving fluoride ion. Part 38. New fluorinated dienes by defluorination

The oligomers 2, 4 and 6, 6a, derived from tetrafluoroethene, octafluorocyclopentene, and hexafluorocyclobutene respectively, are converted into their corresponding dienes 7–9 by defluorination, using sodium amalgam. An alternative route using tetrakis(dimethylamino)ethene (TDAE) is also described and forms a fluoride salt of TDAE. The diene 7 shows a remarkably low extinction coefficient for UV absorption.

Charge-transfer salts containing cyclic perfluorinated anions

Abstract Perfluorobicyclopentenyl (1a) and -butenyl (2a) react with decamethylferrocene (3) , to give charge-transfer salts 4 and 5 , respectively; perfluorohexakis(trifluoromethyl)cyclo-pentadiene (6) forms a salt (8) containing the C 5 (CF 3 ) 5 anion. Crystal structures of the salts 4 and 5 have been determined; both contain centrosymmetric trans -diene radical anions.