| Perfluoro[2.2]paracyclophane and perfluoro[2.2.2]paracyclophane have been successfully synthesized in 42% and 1.2% yield respectively from their precursor, 1,4-bis (chlorodifluoromethyl)-2,3,5,6-tetrafluorobenzene by its reaction with activated zinc dust when heated in anhydrous acetonitrile at 100 °C. Two preparations of the precursor, first from 1,4-dicyano-2,3,5,6-tetrachlorobenzene and an improved method beginning from 1,2,4,5-tetrachlorobenzene, are also described and discussed as are key comparisons to our related synthesis of AF4. Perfluoro[2.2]paracyclophane was then used as starting materials in reactions with a large variety of nucleophiles.;The aromatic fluorines of perfluoro[2.2]paracyclophane are extremely reactive with respect to nucleophilic substitution reactions. Chapter 3 emphasizes products of monosubstitution with hydroxide, alkoxide, tert-butyl lithium, thiolates, amines and dimethyl malonate in the presence of sodium hydride. Reactions of bidentate nucleophiles with perfluoro[2.2]paracyclophane provide cyclic products. All reactions appear to proceed via SNAr mechanisms. Reactivity issues are discussed including the effects of substituents on the further reactivity and regiochemistry of multisubstitution. The UV-vis absorption spectra of products show a progression toward longer wavelength absorption as the substitutents become increasingly electron donating.;Bis-nucleophilic substitutions of F8 with sodium thiolates show replacement of the fluorine atom para to the first substitutent on the same benzene ring. In comparison, treatment of F8 with sodium 4-fluorophenolate or secondary amines gives a mixture of bis-substituted F8 derivatives. Reaction of F8 with 4 equivalents of sodium thiolates furnishes tetrakis-substituted F8 derivatives which contain two regioisomers. Each benzene ring has two substituents para to each other. The ratio of the two isomers is dependent on the group that is attached to sulfur. Treatment of F8 with 4 equivalents of sodium 4-fluorophenolate gives only one isomer. The reaction of F8 with 8 equivalents of pyrrolidines provides two tri-substituted F8 isomers. Treatment of F8 with two equivalents of 1,2-benzene-dithiol in the presence of sodium hydride furnishes bis-cycloadducts on the same benzene ring as a major product. Transannular effects of these products are measured by UV-vis spectra. |
