Photoredox‐Catalyst‐Enabled para‐Selective Trifluoromethylation of tert‐Butyl Arylcarbamates

Abstract The direct incorporation of a trifluoromethyl group on an aromatic ring using a radical pathway has been extensively investigated. However, the direct highly para ‐selective C−H trifluoromethylation of a class of arenes has not been achieved. In this study, we report a light‐promoted 4,5‐dichlorofluorescein (DCFS)‐enabled para ‐selective C−H trifluoromethylation of arylcarbamates using Langlois reagent. The preliminary mechanistic study revealed that the activated organic photocatalyst coordinated with the arylcarbamate led to para ‐selective C−H trifluoromethylation. Ten‐gram scale reaction performs well highlighting the synthetic importance of this new protocol.