A new synthesis of 5-alkyl-2-furancarboxylates and 5-alkyl-2-selenophenecarboxylates via the direct oxidation of 2,4-alkadienoic esters with selenium dioxide is described.
Direct oxidation of 2,4-alkadienoic esters with seleniumdioxide gave 5-alkyl-2-furancarboxylic esters along with 5-alkyl-2-selenophenecarboxylic esters. Ethyl 5-methylfurancarboxylate was converted to 5-hydroxymethyl-2-furancarbaldehyde, a component of honey, via ethyl 5-bromomethyl-2-furancarboxylate (5) in good yield. The compound 5 was converted to (5-ethoxycarbonyl-2-furyl)methyl dimethyldithiocarbamate