5,8-Methano-2H-1-benzopyran-2-one, 6-ethylideneoctahydro- 6- and 7-Ethylideneoctahydro-5,8-methano-2H-1-benzopyran-2-one 69486-14-2 9-Ethylidene-3-oxatricyclo(6.2.1.02,7)undecane-4-one