DIELS-ALDER REACTIONS OF VINYL FLUORIDES WITH 1,3-DIPHENYLISOBENZOFURAN

alpha-Fluorostyrenes synthesized from substituted styrenes by a two-st ep bromofluorination-dehydrobromination procedure and the E/Z-isomers of beta-fluorostyrene do react in thermal [4+2]-cycloadditions with th e super diene 1,3-diphenylisobenzofuran. alpha-Fluorostyrenes are less reactive and the endo/exo ratio is decreased in all cases compared to the parent olefins. Both electron donating and electron withdrawing s ubstituents in the aromatic ring of alpha-fluorostyrenes accelerate th e reaction rate, suggesting a neutral Diels-Alder reaction. Copyright (C) 1996 Published by Elsevier Science Ltd