Polyfluorobicyclo[2,2,2]octanes. Part III. Syntheses and reactions of new mono- di- and trihydrides and derived compounds

Fluorobicyclo2,2,2]octanes as follows were made by fluorination with cobaltic fluoride :- 1H- and 2H- tridecafluoro- ; 1H,2H-, 1H,3H-, 2H,2H-, 2H,3H-, and 1H,4H- dodecafluoro-; 1H,2H,3H-, 1H,2H,4H-, and 1H,3H,3H- undecafluoro-; 2H,2H,3H,3H- decafluoro-. These afforded, by the appropriate dehydrofluorinations, dodecafluoro-; 1H- and 2H- undecafluoro-; 1H,2H-, 1H,3H-, and 1H,4H- decafluoro- bicyclo2,2,2]oct-2-ene. Self-consistent nmr data confirmed all structures. 1H-Trideca- and 1H,4H-dodeca- fluorobicyclo2,2,2]octanes possess acidic bridgehead hydrogens, which are reactive under basic conditions, and may be replaced by various functional groups. 1-Lithiotridecafluorobicyclo2,2,2]octane, a remarkably stable perfluoroalkyl lithium derivative, survived many hours in refluxing ether, but slowly decomposed to 1- substituted undecafluorobicyclo2,2,2]oct- 2-enes, via a transient intermediate, a bridgehead ‘olefin’ ‘violating’ Bredt's rule.