Oxidative Trifluoroacetoxylation of 1°, 2°, and 3° Benzylic C(sp³)-H Bond Donors Using <i>N</i>-Trifluoroacetoxyquinuclidinium Salts under Photoredox Catalysis.

<i>N</i>-Trifluoroacetoxyquinuclidinium trifluoroacetate was prepared <i>in situ</i> from quinuclidine <i>N</i>-oxide and (CF₃CO)₂O. Except for some electron-poor substrates, this reagent allows for the high-yielding oxidative trifluoroacetoxylation of 1°, 2°, and 3° benzylic C-H bonds under photocatalytic conditions. The trifluoroacetoxylation of an ibuprofen methyl ester allowed the selective functionalization of a 2° benzylic C-H bond. For alkylbenzenes, hydrogen-atom transfer from a benzylic C-H bond to a quinuclidine cation radical was proposed to be the reaction-product-determining step.