(4S)-4,5-dihydro-4-ethoxycarbonyloxy-2H-furo[2,3-c]pyran-2-one

ethyl 5-((dimethylamino)methylene)-2-oxo-4-(2-oxoethyl)-2,5-dihydrofuran-3-carboxylate

(4S)-4-acetoxy-4,5-dihydro-2H-furo[2,3-c]pyran-2-one

(Z)-3-deoxy-3-C-[(ethoxycarbonyl)methylene]-1,2-O-isopropylidene-5-O-triphenylmethyl-α-D-erythro-pentose

(4S,7S,7aR)-4,7-dihydroxy-4,5,7,7a-tetrahydro-2H-furo[2,3-c]pyran-2-one