2,7-Dioxabicyclo[3.2.1]octan-3-one,4,6-bis(acetyloxy)-8-[1-(octahydro-4,4,7a-trimethyl-1H-inden-1-yl)ethenyl]-,[1S-[1a,4b,5a,6a,8S*(1S*,3aR*,7aR*)]]-