Selective Oxyfunctionalization of Benzylic C-H with No Solvent.

The direct selective oxyfunctionalization of C-H into C═O represents a highly useful, yet challenging, synthetic methodology. Herein, a one-step oxyfunctionalization of benzylic C-H into aryl ketone, with no overoxidation of the -OH functional group, is reported through mechanochemistry. The substrate scope is also tolerant of a wide range of different functional groups, providing a particularly sustainable yet widely adaptable route for the synthesis of aryl ketones, which represent both a classic synthetic precursor and a useful strategy for lignin monomer valorization. A series of mechanistic and spectroscopic investigations were also conducted to shed light on the unique C-H over -OH selectivity, opening up new avenues for oxidation chemistry.