Visible‐Light‐Initiated Air‐Oxygenation of Alkylarenes to Carbonyls Mediated by CBr4 in Water

The proposal of synthesizing benzyl skeleton derivatives via direct oxidation of functionalized benzylic C–H bonds has received extensive research attention. Herein, a method was developed to prepare carbonyl compounds via photoinduced aerobic oxidation of ubiquitous benzylic C–H bonds mediated by bromine radicals and tribromomethane radicals. This method employed commercially available CBr4 as a hydrogen atom transfer reagent precursor, air as an oxidant, water as a reaction solvent, and tetra-butylammonium perchlorate (TBAPC) as an additive under mild conditions. A series of substrates bearing different functional groups was converted to aromatic carbonyls in moderate to good yields. Moreover, a low environmental factor (E-factor value = 0.45) showed that the proposed method is ecofriendly and environmentally sustainable.