Synthesis of β-Halobutenolides and Their Pd(0)/CuI-Catalyzed Cross-Coupling Reactions with Terminal Alkynes. A General Route to β-(1-Alkynyl)butenolides

Pd(0)/Ag+-Cocatalyzed Cyclization Reaction of 1,2-Allenic Carboxylic Acids with Aryl/Alkenyl Halides. An Efficient Synthesis of Butenolides

Efficient Synthesis of 4-Halo-4-penten-2-ones and 3-Halo-3-butenoic Acids/Esters via Hydrohalogenation Reaction of 3,4-Pentadien-2-one and 2,3-Butadienoic Acid/Methyl Ester