Direct cyclization of 1,3-diaryl propargylic alcohols with β-dicarbonyl compounds by palladium-boric acid dual-catalyst system

Palladium and boric acid-catalyzed cyclization of underivatized 1,3-diaryl propargylic alcohols with 1,3-cyclohexanediones has been developed. Boric acid plays a role for the efficient activation of the propargylic alcohols. Various substituted tetrahydrobenzofuranones were obtained in moderate to good yields. Reactions using 4-hydroxy-2-pyrones as the nucleophile also proceeded to afford the substituted dihydrofuropyranones.

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