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

5-Hydroxyfuran-2(5H)ones are an important class of compounds because they often occur in natural products and exhibit a broad range of biological activities. Recently, much attention has been focused on the efficient and di verse synthesis of these compounds, particularly 4-halo-5-hydroxy-2(5H)-furanones. The typical synthetic strategies include acid catalyzed cyclization of ketonic acids, auto oxidation of corresponding lactone in air, rearrangement reactions of α-phenylsulphinylacrylates, oxidation with chromium trioxide in acetic acid, and bromination-hydrolysis of α ,β-butanolides. Herein, we wish to report that 4-halo-5-hydroxyfuran-2(5H)-ones were synthesized via the efficient sequential halolactonization-hydroxylation reaction of 4-aryl-2,3-allenoic acids with I2 or CuX2 (X = Br or Cl) inmoderate to good yields.……