The photoisomerisation of α-tropolone

Abstract

α-Tropolone photoisomerises in hexane via 5-hydroxybicyclo[3,2,0]hepta-2,6-dien-4-one (III) to a mixture of bicyclo[3,2,0]hept-2-ene-4,6-dione and bicyclo-[3,2,0]hept-2-ene-4,7-dione; the hydroxy-ketone (III) is also formed when α-tropolone is irradiated in water and in methanol.