4-Pentyne-1, 3-dione derivatives having various substituents were conveniently synthesized from ynals and silyl enol ethers in two steps. The cyclization behaviors of the obtained 4- pentyne-1, 3-diones were studied. γ-Pyrones and 3 (2H)-furanones were obtained by cyclization in the presence of an acid or base as a catalyst. The selectivity of the cyclization was moderately influenced by the substituents at the acetylenic moiety.
