Diels-Alder reactions of vinyl fluorides with 1,3-diphenylisobenzofuran

Abstract α-Fluorostyrenes synthesized from substituted styrenes by a two-step bromofluorination-dehydrobromination procedure and the E Z - isomers of β-fluorostyrene do react in thermal [4+2]-cycloadditions with the super diene 1,3-diphenylisobenzofuran. α-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 substituents in the aromatic ring of α-fluorostyrenes accelerate the reaction rate, suggesting a neutral Diels-Alder reaction.