A Simple Synthetic Method for γ-Methylene-γ-butyrolactones from Diallyl 2-Propynylmalonates by Palladium-Catalyzed Cyclization and Hydrogenolysis with Formic Acid - Mandai, Tadakatsu; Ohta, Kazumi; Baba, Norimitsu; Kawada, Mikio; Tsuji, Jiro (Synlett, 1992)