2H-Furo(2,3-F)(2)benzopyran-2,8(3H)-dione, 5A-ethenyloctahydro-4-hydroxy-3,9-bis(methylene)-, (3ar,4S,5ar,9ar,9br)-

2H-Furo(2,3-f)(2)benzopyran-2,8(3H)-dione, 3a-beta,4,5,5a,6,9,9a-beta, 9b-alpha-octahydro-3,9-dimethylene-4-beta-hydroxy-5a-beta-vinyl-, (+)-