Efficient synthesis of functionalized hydrofurans and pyrrolsemploying hexachloroacetone

Isocyanides react smoothly with dimethyl acetylenedicarboxylate in the presence of hexachloroacetone to produce dimethyl 5-[alkyl(aryl)imino]-2,2-bis(trichloromethyl)-2,5-dihydro-furan-3,4-dicarboxylates in high yields. When the reaction was performed in the presence of dibenzoylacetylene, 3-benzoyl-1-alkyl-4-chloro-5- hydroxy-5-phenyl-1,5-dihydro-2H-pyrrol-2-ones were obtained.