6-Endo-Dig vs. 5-Exo-Dig ring closure in o-hydroxyaryl phenylethynyl ketones. A new approach to the synthesis of flavones and aurones

…, S Iborra, J Primo, MA Miranda

文献索引：Garcia, Hermenegildo; Iborra, Sara; Primo, Jaime; Miranda, Miguel A. Journal of Organic Chemistry, 1986 , vol. 51, # 23 p. 4432 - 4436

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被引用次数: 65

摘要

The aryl phenylpropynoates 3a-c, prepared by esterification of phenylpropynoic acid with the corresponding phenols, by means of N,"-dicyclohexylcarbodiimide, give upon irradiation the o-hydroxyaryl phenylethynyl ketones 4a-c. The cyclization of these compounds in basic media follows two alternative pathways: 6-endo-dig ring closure, to give the flavones 8a-c, and/or 5-exo-dig ring closure, to give the aurones 9a-c. The predominance of one or the ...