The reaction of 1, 3-dicarbonyl compounds with various α-haloketones in the presence of ammonium acetate in aqueous ethanol

The reaction of 1, 3-dicarbonyl compounds with ethyl bromopyruvate thus led to dihydrofurans in good yields. Dihydrofurans were converted to the corresponding furan derivatives in the presence of p-toluenesulfonic acid (p-TSA). Under similar conditions, however, the reactions of α-haloketones 3-chloropentane-2, 4-dione and methyl 2-chloro-3-oxobutanoate with 1, 3-dicarbonyl compounds led directly to fused furan derivatives in good yields. While, the reaction of phenacyl bromides with 1, 3-dicarbonyl compounds led to either esters or α-substituted acetophenones in moderate yields.