Robust Bio-derived Polyoxometalate Hybrid for Selective Aerobic Oxidation of Benzylic C(sp3)–H Bonds

Utilization of natural resources to construct functional catalytic materials for challenging organic reactions is of great importance in the chemical community, which has achieved significant attention. Herein, we describe the synthesis of a robust bio-derived polyoxometalate (POM) hybrid by the reaction of the naturally occurring phytic acid (PhyA) with MoO3, and the obtained hybrid was denoted PhyA–Mo. Systematic studies revealed that the multi-phosphate structure of PhyA enabled the synthesized PhyA–Mo to simultaneously possess a higher concentration of surface-active oxygen species and more negatively charged Mo sites, which played the role of catalytically active sites for aerobic oxidation. These two types of active sites together enabled the PhyA–Mo to show outstanding catalytic activity for aerobic oxidation of benzylic C(sp3)–H in different substrates to generate various carbonyl compounds without using any additional initiator. Importantly, the fact of realizing aerobic oxidation of benzylic C(sp3)–H bonds efficiently over POM-based materials in the absence of any radical initiator represented the main finding and the major breakthrough. Especially, this work provided a general and useful strategy to improve the catalytic performance of POM-based materials by using phosphoric acids containing multi-phosphate groups.