Abstract
A photoredox‐catalyzed and copper‐promoted trifluoromethoxylation of arenediazonium tetrafluoroborates have been developed for the first time. Trifluoromethyl arylsulfonate (TFMS) was used as the trifluoromethoxylation reagent. This reaction is scalable and proceeds regioselectively under mild reaction conditions. Furthermore, mechanistic studies suggested that Cs[Cu(OCF3)2] intermediate might be generated during the reaction.