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. y-Pyrones and 2-alkylidene-2,3-dihydro-3-fu-ranones were obtained by the triethylamine-catalyzed cyclization of the 4-pentyne-l,3-dione system having a dike-tone 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.
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