An efficient synthesis of 4-halo-5-hydroxyfuran-2(5H)-ones via the sequential halolactonization and γ-hydroxylation of 4-aryl-2,3-alkadienoic acids

4-Halo-5-hydroxyfuran-2(5H)-ones were synthesized via the efficient sequential halolactonization-hydroxylation reaction of 4-aryl-2,3-allenoic acids with 12 or CuX2 (X = Br or Cl) in moderate to good yields. The structures of the products were established by the X-ray single-crystal diffraction study of 3-methyl-4-iodo-5-phenyl-5-hydroxyl-2(5H)-furanone (2a). A rationale for this reaction was discussed based on some brief mechanistic study.