Regioselective Reaction between Maltol and Vinyltriphenylphosphonium Salts: An Efficient One-Pot Synthesis of a Novel Class of Dihydrofuran and Cyclobutene Derivatives

The reaction of 2-methyl-3-hydroxy-4H-pyrane-4-one (maltol) with dialkyl acetylenedicarboxylates in the presence of triphenylphosphine in CH2Cl2 at room temperature leads to the unknown fused furan and cyclobutene derivatives, and functionalized olefins in fairly high yields.