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A new approach for the synthesis of 4-pyrones with broader substrate scope and functional group tolerance is described. The reaction proceeds via an initial 1,4-addition by piperidine, followed by nitrogen-assisted… Click to show full abstract
A new approach for the synthesis of 4-pyrones with broader substrate scope and functional group tolerance is described. The reaction proceeds via an initial 1,4-addition by piperidine, followed by nitrogen-assisted 6-endo-dig cyclization and hydrolysis. 1,3-Diynones with nonenolizable electron-withdrawing ketones and nonpropargylic H provide relatively high yields. For substrates with particular R2 substituents, 1,4- or 1,6-adducts were isolated, suggesting that steric and electronic factors of the R2 substituent should have a strong impact on the 6-endo-dig cyclization.
Journal Title: Organic letters
Year Published: 2022
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