One-Pot Synthesis of E-Alkylidene Derivatives of 3H-Furan-2-ones from 4-Pentynoic Acid and Aldehyde

4-Pentynoic acid reacts with aldehyde under the co-catalyst system of Wilkinson’s complex and 2-aminopyridine to give E-alkylidene derivatives of 3H-furan-2-one through the transition metal-catalyzed cyclization of 4pentynoic acid followed by condensation of the resulting lactone with aldehyde.