The photorearrangement of 6-acetoxy-3,5-bis(chloromethyl)-2,4,6-trimethylcyclohexa-2,4-dienone
Abstract
U.v. irradiation of 6-acetoxy-3,5-bis(chloromethyl)-2,4,6-trimethylcyclohexa-2,4-dienone causes its highly stereoselective rearrangement to exo-6-acetoxy-1,4-bis(chloromethyl)-3,5,6-trimethylbicyclo[3,1,0]hex-3-en-2-one. This readily eliminates acetyl chloride to give a 5-methylenecyclopent-2-enone. These results help to establish the overall mechanism of the photoisomerisation of heavily substituted cyclohexa-2,4-dienones to bicyclo[3,1,0]hex-3-en-2-ones.