Efficient synthesis of functionalized furans using multicomponent reactions of ethyl bromopyruvate

The reaction of dialkylacetylenedicarboxylates or diaroylacetylenes with ethyl bromopyruvate in the presence of enaminones led to 2-ethyl 3,4-dialkyl 4-bromo-4,5-dihydro-2,3,4-furan tricarboxylates or ethyl 3,4-diaroyl-4-bromo-4,5-dihydro-2-furoate, in excellent yield. These compounds are quantitatively converted to the corresponding 2,3,4-trisubstituted furans by 4-dimethylaminopyridine.