cis-1,2,3,6-Tetrahydro-4-methylphthalsureanhydrid

cis-1,2,3,6-tetrahydro-4-methylphthalic anhydride

rel-3aα*,4,7,7aα*-Tetrahydro-5-methyl-1,3-isobenzofurandione

(3aS,7aR)-5-methyl-3a,4,7,7a-tetrahydroisobenzofuran-1,3-dione