STRUCTURAL ASSIGNMENT OF THE INTRAMOLECULAR META PHOTOCYCLOADDUCT ISOMERS FROM 4-PHENOXYBUT-1-ENES AND 3-BENZYLOXYPROP-1-ENES BY PROTON NMR-SPECTROSCOPY

H-1 NMR data (400 and 500 MHz) are reported for the intramolecular met a photocycloaddition products from 4-phenoxybut-1-enes and 3-benzyloxy prop-1-enes. The structures of these photoproducts, and in particular the discrimination between the 1,6- and 7,8-bridged isomers, are deduc ed from COSY 45 and 60 experiments and spin-decoupling techniques.