1,4-Methanocyclopent[3,4]oxepino[4',3':4,5]pyrrolo[2,1-b]oxazol-3(1H)-one,decahydro-10b-methyl-11-(1-methylethyl)-, (1R,4R,4aS,6aR,6bR,10aS,10bR,11S)-