Synthesis of novel bicyclic prostaglandins by photochemical cycloaddition reactions

Abstract

Light-induced addition reactions of cyclopentenone derivatives with ethylene, followed by elaboration of the alkyl chains at positions 8 and 12, give bicyclic prostanoic acid analogues belonging to the prostaglandin E₂ and F_2α series. Cycloaddition of ethylene to prostaglandin A₂ methyl ester yields simultaneously the α- and β-cyclo-adducts. Photochemical addition of allene to prostaglandin A₂ derivatives affords mixtures of photoadducts which vary with the nature of the functional group at position 15, thus illustrating the versatility of these photocondensation reactions.