(1<i>S</i>,1′<i>S</i>,2′<i>R</i>,4a'<i>S</i>,9a'<i>S</i>,9b'<i>R</i>)-1′-Acetyloxy-2,4′-dioxo-2′,4′,4a',7′,8′,9′,9a',9b'-octahydro-1′<i>H</i>,2<i>H</i>-spiro[acenaphthylene-1,5′-pyrano[4,3-<i>a</i>]pyrrolizin]-2′-ylmethyl acetate
Acta crystallographica. Section E