2,7-Dioxabicyclo[3.2.1]octan-3-one,6- (acetyloxy)-8-[1-[(1R,3aS,7aS)-octahydro-4,4,- 7a-trimethyl-1H-inden-1-yl]ethenyl]-,(1S,- 5R,6S,8R)-rel-(-)-