K₂S₂O₈‐Mediated 1,2‐Hydroxycarbonylation of Alkenes to Construct Hydroxyl‐Functionalized Chroman‐4‐Ones

Abstract

Difunctionalization of alkenes allows the rapid construction of complex molecules with high selectivity and efficiency in organic synthesis. Herein, we first describe a 1,2‐hydroxycarbonylation of alkenes for the preparation of hydroxyl‐functionalized chroman‐4‐ones through the cooperative action of inorganic oxidants and organic acids. The transformation is initiated by the formation of an acyl radical, and then experiences intramolecular 6‐exo‐trig radical cyclization and hydroxylation process. It is notable that the hydroxyl group in the final products originate from organic acids without the use of any transition‐metal catalysts. To further demonstrate the practicality and mechanism of this method, the gram‐scale reaction and a series of control experiments including gas chromatography‐mass spectrometry (GC‐MS) and infrared (IR) absorption spectroscopy experiments were performed, and the corresponding intermediates were successfully captured.