DL-3-[(2,5-Dihydro-3-methyl-2-oxo-5-furyl)oxymethyl ene]-3,3a,6,6a-tetrahyd
ro-2H-cyclopenta[b]furan-2-one, C13H12O5, has relative configurations at th
e asymmetric C atoms of 3aS, 6aS and 5'R. The dihedral angle formed by the
fused cyclopentene and furan rings is 114.81 (5)degrees, and these rings fo
rm dihedral angles of 119.53(5) and 67.68 (5)degrees, respectively, with th
e methylfuranone ring.