Reduction of Perfluorinated Benzocycloalkenones and Other Polyfluoroaryl Ketones to Alcohols with LiBH4

The reduction of polyfluorinated benzocycloalken-1-ones, perfluoro-2,3-dihydrobenzofuran-3-one, and perfluorinated diaryl and alkyl aryl ketones with lithium tetrahydridoborate in diethyl ether gave the corre­sponding alcohols. The reduction of perfluorinated 2-methyl- and 2-hydroxy-2-phenylbenzocyclobutenones was accompanied by opening of the four-membered ring with the formation of (perfluoro-2-vinylphenyl)­methanol and [2-(hydroxymethyl)tetrafluorophenyl](pentafluorophenyl)methanol, respectively. Polyfluorinated benzocycloalkenediols were obtained in the reduction of dicarbonyl derivatives of perfluorinated benzocyclo­butene, indan, and tetralin.