The photo-cycloaddition of vinyl acetate to benzene and its simple derivatives: functionalisation of the dihydrosemibullvalene skeleton

Abstract

The photo-reaction of vinyl acetate with benzene yields both ortho- and meta-cycloadducts in an initial ratio of 1 : 7. The ortho-product has endo-stereochemistry but a mixture of regio- and stereo-isomers result from the meta-cycloaddition. Base-catalysed hydrolysis of the meta-adducts yields the corresponding alcohols, whereas acid treatment gives 2-substituted derivatives of bicyclo[3.3.0]octa-3,7-diene. The photo-reaction of vinyl acetate with toluene, anisole, fluorobenzene, and p-xylene also yields meta-cycloadducts : the results are discussed in terms of previously proposed reaction intermediates.