(1′R,2R,2′S,3′S,7′S,8′R,9′R,10′R,12′R,13′R,14′R,15′R,18′R)-14′-Chloro-13′-(hydroxymethyl)-8′,18′-dimethyl-17′-oxospiro[oxirane-2,4′-[11,16,19]trioxapentacyclo[11.5.1.0~1,15~.0~3,8~.0~10,12~]nonadecane ]-2′,7′,9′-triyl triacetate