2,5-Ethanoindeno[4,5-e]oxecin-3,11,15-trione,5,6,7,8,8a,10a,12,13,13a,13b-decahydro-7-hydroxy-12-methyl-,(1Z,5R*,7R*,8aS*,10aS*,12R*,13aR*,13bS*)-(+)-