Base-free copper-catalyzed aerobic oxidation of benzylic alcohols with N-benzylidene-N,N-dimethylthane-1,2-diamine and TEMPO

Selective oxidation of alcohols using N-benzylidene-N,N-dimethylthane-1,2-diamine, CuBr2 and TEMPO as the catalytic system was developed. Catalyzed by this simple catalytic system in the absence of any external base, various benzylic alcohols could be oxidized to their corresponding aldehydes with excellent yields in CH3CN/H2O (v/v = 1/1) under 0.2 MPa O2 at 80 °C.

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► N-benzylidene-N,N-dimethylthane-1,2-diamine, CuBr2 and TEMPO as a catalyst system.
► The simple ligand could be easily synthesized.
► Efficient aerobic oxidation of benzylic alcohols into aldehydes under mild conditions.
► the oxidations occurred well without any external base, being unlike the previous Cu/TEMPO systems.