Propanedioic acid, bis(2,3,3a,4,4a,5,7a,8,9,9a-decahydro-4a,8-dimethyl-3-methylene-2,5-dioxoazuleno(6,5-b)furan-4-yl) ester, (3aR-(3alpha,4alpha(3'aR*,4'S*,4'aR*,7'aR*,8'R*,9'aR*),4abeta,7aalpha,8alpha,9aalpha))-