Conversion of aryl CO to CC bond through a UV light activation/TEMPO oxidation cascade reaction

Metal free conversion of aryl CO to CC bond through a photochemical rearrangement/oxidation cascade reaction is described. Irradiation of O-acetyl aryloxy benzene derivatives in benzene solution undergoes a unique photochemical rearrangement reaction to afford the ketal compounds, which are sequentially oxidized by 2,2,6,6-tetramethylpiperidine 1-oxyl (TEMPO) to yield the diketone compounds.

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► The direct conversion of aromatic CO to CC without metallic catalyst was developed.
► The conversion could be realized by a hν activation/TEMPO oxidation cascade reaction.
► The photochemical approach could compensate the Friedal–Crafts acylation reaction.
► The research enriches the application of photochemical reactions in organic synthesis.