Addition of molecular fluorine to bicyclo[2.2.1]hept-2-ene derivatives having electronegative substituent(s) on the ethano bridge has been found to give exo,exo-difluoro adducts with high stereoselectivity. The difluoro adducts derived from 2-azabicyclo[2.2.1]hept-5-en-3-ones having an electron-withdrawing group at 2-position were converted to the difluorinated carbocyclic nucleoside analogs.
Addition of molecularfluorine to bicyclo[2.2.1]hept-2-ene derivatives has been found to give exo,exo-difluoro adducts in fair yields. The difluoro adduct (13c) was converted to the fluorine containing carbocyclic adenosine and guanosine analogs.