Pd-Promoted Cyclization of (Z)-Pent-2-en-4-yn-1-yl Alkanoates Leading to Furans via an Acyl Group Shift and Further Synthetic Transformation.

Palladium-promoted acyl migration was observed in the reaction of (Z)-pent-2-en-4-yn-1-yl alkanoates in the presence of DBU to yield 2-(alkanoylmethyl)furan derivatives (2) in high yields. Compounds 2 then underwent oxidative decarbonylation to afford 2-acylfurans with O2 as the oxidant under mild and metal-free conditions. The mechanistic pathway of the reaction involving an intramolecular cyclization and acyl group shift is discussed.