Synthesis and Triethylamine‐catalyzed Cyclization Reaction of 4‐Pentyne‐1,3‐dione System Having Various Substituents

4‐Pentyne‐1,3‐dione system having various substituents was synthesized in two steps and the cyclization behavior of the obtained 1,3‐dicarbonyl compounds was examined. γ‐Pyrones and 2‐alkylidene‐2,3‐dihydro‐3‐furanones were obtained by the triethylamine‐catalyzed cyclization of the 4‐pentyne‐1,3‐dione system having a diketone moiety. Furthermore, a phenol derivative was obtained in the case of 4‐pentyne‐1,3‐dione system having an ester moiety. Thus, it was found that the kind of substituents in the 4‐pentyne‐1,3‐dione system remarkably influenced the selectivity in the cyclization.