PHOTO-CHEMICAL REACTIONS .103. PHOTOCHEMISTRY OF CONJUGATED-GAMMA,DELTA-EPOXY-ENE-CARBONYL COMPOUNDS OF THE IONONE SERIES - UV-IRRADIATION OF ALPHA,BETA-UNSATURATED EPSILON-OXO-GAMMA,DELTA-EPOXY COMPOUNDS AND INVESTIGATION OF THE MECHANISM OF THE ISOMERIZATION OF EPOXY-ENONES TO FURANES