FLUORINATED DI-ENES

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 cydopentadienylide derivatives with difunctional carbon nucleophiles and a cyclopentadienylide salt (17) is obtained in a remarkable 'one-pot' reaction from hexachlorobutadiene. [GRAPHICS] principles for the construction of super-strong electron-withdrawing substituents and superstrong acids. This approach consists in replacing the sp(2)-oxygen atom in various groups with the =NSO2CF3 radical and has been confirmed by examples of substituents with the central atoms consisting of sulfur in different valence states, carbon, phosphorus and iodine. From this principle, a stable substituent with sigma(p) constant 1.76, equal to three nitro groups in its influence toward benzene nuclei, has been constructed.