Photoreaction of 1,5-DIMETHYL-6-OXACYCLOPROPYLIDENETRICYCLO[3.2.1.02,7]OCT-3-EN-8-ONE: A Novel Type of Addition of Ketene With the Moiety Containing an Epoxide Ring

Abstract

1,5-Dimethyl-6-oxacyclopropylidenetricyclo[3.2.1.02,7] oct-3-en-8-one (II), upon irradiation, afforded 4,8-dimethyl-1,4-dihydrobenzopyran-3-one (III). This rearrangement was considered to be a novel ene-type reaction of photochemically generated ketene with the moiety involving an epoxide ring. The ketene intermediate was detected by low temperature ir spectrum as well.