An efficient synthesis of dihydrofurans and furans by a reaction between 1,3-dicarbonyl compounds and ethyl bromopyruvate, ethyl 2-chloroacetoacetate, or 3-chloroacetylacetone in the presence of ammonium acetate in aqueous ethanol is described. When the reaction was performed with a phenacyl bromide, O-alkylation of 1,3-dicarbonyl compounds occurred without cyclization.