REGIOSPECIFIC 2+2 PHOTOADDITION OF PHENYL SUBSTITUTED ACETYLENES TO PENTAFLUOROPYRIDINE

Article abstract of DOI:10.1016/S0040-4020(01)80039-9

Irradiation of a cyclohexane solution of pentafluoropyridine and 1-phenyl-2-alkyl-acetylenes produced regiospecific 2+2 photocycloaddition, thus forming 3-aza-bicyclo<4.2.0> octa-2,4,7-triene derivatives, which further phototransformed to 7-aza-tricyclo<4.2.0.0^2,5>octa-3,7-diene derivatives.Further phototransformation of the tricyclic system depended on the alkyl substituent: in the case of tert-butyl, 1,2,5,6,7-pentafluoro-3-tert-butyl-4-phenyl-8-aza-bicyclo<4.2.0>octa-2,4,7-triene was formed, while in the case of a methyl substituent, 1-methyl-2,3,5,6,7-pentafluoro-8-phenyl-4-aza cycloocta-1,3,5,7-tetraene resulted.