Analogues of the Quararibea metabolite chiral enolic-gamma-lactone from (2S,3S)- and (2S,3R)-tetrahydro-3-hydroxy-5-oxo-2,3-furandicarboxylic acids

Abstract

Reaction of dialkyl (2S,3S)- or (2S,3R)-tetrahydro-3-hydroxy-5-oxo-2,3-furandicarboxylates with POCl3 in pyridine followed by diazomethane resulted in the isolation of dialkyl 2S-4-methoxy-5-oxo-2,5-dihydro-2,3-furandicarboxylates, which are analogues of the Quararibea metabolite chiral enolic-gamma-lactone (3-hydroxy-4,5-(R)-dimethyl-2(5H)-furanone). An unusual alpha-hydroxylation of gamma-butyrolactone takes place involving POCl3 in pyridine. When the dehydration was facilitated with methanesulfonyl chloride in triethylamine, instead of POCl3, aromatic dialkyl 5-[(methylsulfonyl)oxy]-2,3-furandicarboxylates were obtained.