6β-Angeloyloxy-4α-hydroxy-9-oxofuranoeremophilane

(4S)-4a,5,6,7,8,8aβ-Hexahydro-3,4aβ,5β-trimethyl-5-hydroxy-4β-[(Z)-2-methyl-2-butenoyloxy]naphtho[2,3-b]furan-9(4H)-one

(Z)-2-Methyl-2-butenoic acid (4S)-4,4a,5,6,7,8,8aβ,9-octahydro-5α-hydroxy-3,4aβ,5-trimethyl-9-oxonaphtho[2,3-b]furan-4β-yl ester