Synthèse de la diméthyl-4,4-dihydrofuranedione-2,3

4,4-Dimethyl-dihydro-2,3-furanedione ( 4 ), an intermediate in the synthesis of (+)-D -pantothenic acid, is obtained in good yield from readily available substances such as isopropyl chloride, diethyl oxalate and formaldehyde, without oxidative conditions.