Metal-Free Aerobic C–H Oxidation of Methylarenes to Aromatic Aldehydes by Sulfur-Containing Tetracyclic Compounds as Visible-Light Photocatalysts

抄録

Oxidation of benzylic sp³ C–H bonds smoothly proceeded at ambient temperature under blue LED (465 nm) photo-irradiation using sulfur-containing tetracyclic compounds as photocatalysts. The use of 1,1,1,3,3,3-hexafluoro-2-propanol (HFIP) as a co-solvent was the key to success: various toluene derivatives were selectively oxidized to substituted benzaldehydes without over-oxidation. Preliminary mechanism studies were undertaken, including electron spin resonance (ESR) spectroscopy analyses.