Reusable Palladium Nanoparticles Catalyzed Oxime Ether Directed Mono Ortho-Hydroxylation under Phosphine Free Neutral Condition

An efficient, reusable and stable binaphthyl stabilized Pd-nanoparticles (Pd-BNP) catalyzed the direct ortho-C−H hydroxylation of acetophenone oxime ethers under neutral and phosphine ligand-free condition has been developed. A readily available, economic, safe and greener oxidant oxone has been used in this direct ortho-hydroxylation. The scope of the reaction has been studied with various acetophenone oxime ethers including electron rich to electron deficient system and the reaction afforded only mono hydroxylated products in a highly regioselective manner. Several control experiment results confirmed that the oxone is the hydroxyl source. The Pd-BNP catalyst has been reused up to five times. The heterogeneous test confirmed that the reaction is catalyzed by the heterogeneous Pd-BNP catalyst. (Figure presented.).