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Metal-free Synthesis of Ynones from Acyl Chlorides and Potassium Alkynyltrifluoroborate Salts
Published on: February 24, 2015
Synthesis of γ-Pyrones from Formal [4 + 2] Cyclization of Ketene Dithioacetals with Acyl Chlorides
Mingshan Wang1, Lou Shi1, Yifei Li1
1Jilin Province Key Laboratory of Organic Functional Molecular, Design & Synthesis, Department of Chemistry , Northeast Normal University , Changchun 130024 , China.
Abstract:
A formal [4 + 2] cyclization of easily available ketene dithioacetals with acyl chlorides has been developed. Mediated by lithium bis(trimethylsilyl)amide, a series of γ-pyrones were obtained with a broad substrate scope. This unprecedented formal [4 + 2] cyclization provides a novel mode for ketene dithioacetals as versatile synthons. The synthesized γ-pyrones could be successfully transformed to 2-aryl/amino γ-pyrones and 2,3-dihydroimidazo[1,2-a]pyridin-7(1H)-ones mainly via the cleavage of the C-S bond.
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