PHOTOCHEMICAL REDUCTION OF F-ADAMANTYL HALIDES - A FACILE SYNTHESIS OF HYDRYLFLUOROCARBONS FROM CHLOROFLUOROCARBONS

1-Chloro- and 2-chloro-F-adamantanes, 1,2- and 1,3-dichioro-F-adamantanes, 1,3,5-trichloro-F-adamantane, 1,3,5,7-tetrachloro-F-adamantane, 1-bromo-F-adamantane, and 1-iodo-F-adamantane dissolved in CFCl3 are conveniently dehalogenated in the presence of methanol, hexane, or other hydrogen donor cosolvents by ultraviolet irradiation. The reactions are very clean with isolated yields in the range of 80%-90%. Generally, irradiation times increase when large batches of material are photolyzed and when the less reactive secondary F-adamantyl chlorides are reduced. By controlling the irradiation time, polychloro-F-adamantanes can be reduced in a stepwise manner. Only free-radical, not ionic, products are isolated. A possible mechanism for this photochemical reduction is discussed.