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

Abstract

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 tetrabutylammonium 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.

Boosting Solvent-Free Aerobic Oxidation of Benzylic Compounds into Ketones over Au-Pd Nanoparticles Supported by Porous Carbon

“…Various catalysts, including MnO 2 @Fe 3 O 4 nanoparticles [10], Cu 3 (PO 4 ) 2 [11], LaMO 3 (M = Cr, Co, Fe, Mn, Ni) perovskites [12], and Cr/MCM-41 [13], have been explored for the oxidation of the C-H bonds of benzyl compounds by combining with oxidants. In general, these catalytic systems still required a large amount of toxic or volatile organic solvents (e.g., ethanol, acetonitrile, dichloromethane, and chlorobenzene) and various oxidants (e.g., alkyl hydroperoxide, hydrogen peroxide (H 2 O 2 ), and iodosobenzene) [12][13][14][15][16]. This would result in difficulty in product separation and purification, increasing energy consumption, and generating lots of poisonous and harmful wastewater in the production processes.…”