Development of a Rhodium(II)-Catalyzed Chemoselective C(sp3)H Oxygenation.

We report the first example of Rh^II-catalyzed chemoselective double C(sp³)H oxygenation, which can directly transform various toluene derivatives into highly valuable aromatic aldehydes with great chemoselectivity and practicality. The critical combination of catalyst Rh(OAc)₂, oxidant Selectfluor, and solvents of TFA/TFAA promises the successful delivery of the oxidation with satisfactory yields. A possible mechanism involving a unique carbene-Rh complex is proposed, and has been supported by both experiments and theoretical calculations. [ABSTRACT FROM AUTHOR]