Synonyms: (-)-Bakkenolide C;(1'R,3R,7'aβ)-1'β-Hydroxy-3'aβ,4'β-dimethyl-4-methylene-7'α-[[(2Z)-2-methyl-2-butenoyl]oxy]spiro[oxolane-3,2'-hydrindane]-2-one;(Z)-2-Methyl-2-butenoic acid [(3R,3'aα)-4,5,1',3',3'a,4',5',6',7',7'a-decahydro-3'α-hydroxy-7'α,7'aα-dimethyl-4-methylene-2-oxospiro[furan-3(2H),2'-[2H]inden]-4'β-yl] ester;Bakkenolide C