Polyfluorinated alkenes and alkynes

Abstract

The research described within this thesis may be divided into four main subject areas: 1) The use of (Z)-2H-heptafluorobut-2-ene (10) as a synthon for hexafluorobut- 2-yne (4) in Diels-Alder reactions was investigated. Novel 'one-pot' routes to a variety of bis(trifluoromethyl) substituted furan and arene derivatives were discovered, along with the synthesis of the novel diene, bis(trifluoromethyl)cyclopentadiene (46), from cyclopentadiene.2) A variety of nucleophiles were successfully reacted with (10), the products of which were identical to those that have been, or would be expected to be, formed from the reaction of the same nucleophile with (4). A novel route to a fluorinated quinoline derivative was also discovered.3) Perfluoroperhydrophenanthrene (74) was used as a 'bulking agent' to replace the hydrocarbon solvent used in halogen exchange reactions for the preparation of octafluorocyclopentene (3), chlorofluoro -pyridine, -pyrimidine, and -benzene derivatives. New 'one-pot' syntheses of hexafluorobut-2-yne (4), octafluorobut-2-ene (6) and hexafluorocyclobutene (2) were also discovered.4) Various routes were explored in an attempt to improve the present literature preparations of tetrafluoropropyne (79), including pyrolysis and elimination methods. Tetrafluoroallene (81), and trace amounts of (79), were found to be formed on the elimination of hydrogen fluoride from 2H-pentafluoropropene (5).