Tetrahedron letters

Synthesis of 3-alkenyl-2-arylchromones and 2, 3-dialkenylchromones via acid-catalysed retro-Michael ring opening of 3-acylchroman-4-ones

DS Clarke, CD Gabbutt, JD Hepworth, BM Heron

Index: Clarke, David S.; Gabbutt, Christopher D.; Hepworth, John D.; Heron, B. Mark Tetrahedron Letters, 2005 , vol. 46, # 33 p. 5515 - 5519

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Citation Number: 22

Abstract

3-Acylchromones and 3-acylflavones, readily available by acylation of 2′- hydroxydibenzoylmethane with acid anhydrides in the presence of base, undergo efficient conjugate reduction with NaBH4 in pyridine to give the corresponding chroman-4- ones/flavanones in high yields. The reduction is both regio-and chemoselective. Treatment of the chroman-4-ones with MeSO3H generates the 3-alkenyl-2-arylchromones by a ...