SPIRO[2,5-ETHANOOXIRENO[3,4]CYCLOPENTA[1,2-C]- PYRAN-6(1BH),2'-OXIRANE]-3,7(2H)-DIONE,TETRAHYDRO- 1B-HYDROXY-5A-METHYL-8-(ISOPROPYL)-,(1AS,1BR,2S,2'R,5S,5AR,6AR,8S)-