Efficient Oxidation of Benzylic and Aliphatic Alcohols Using a Bioinspired Cross‐Bridged Cyclam Manganese Complex with H₂O₂

Abstract

The cross‐bridged cyclam manganese complex Mn(Me2EBC)Cl2 efficiently catalyzes the oxidation of benzylic and aliphatic alcohols at pH 3 in a mixture of acetonitrile and water at room temperature. The environmentally benign and high oxygen content oxidant H2O2 was adopted. Conversions of the alcohols to the corresponding carbonyl compounds reached 98 % with good to excellent selectivity. In addition, several lignin model compounds were also catalytically oxidized under these conditions, with excellent conversion (up to 96 %) and selectivity (up to 99 %).

Selective Aerobic Oxidation of Benzyl Alcohols with Palladium(0) Nanoparticles Suspension in Water

“…benzaldehyde) were observed. While some reports exist with for example homogeneous Mn/H 2 O 2 systems [57,66], to the best of our knowledge this is the first example of the oxidation of this compound in the presence of a Pd/O 2 /water system [67][68][69]. This is encouraging for the transformation of more functionalized substrates.…”

“…Based on this, the potential of the NPs suspension was assessed for the oxidation of other substrates modelling the lignin structure under the same conditions [57] (Table 2). First we observed that the reaction was less efficient using 2-methoxybenzyl alcohol (entry 1) with a maximum yield of 21%.…”

Cyclohexene Promoted Efficient Biomimetic Oxidation of Alcohols to Carbonyl Compounds Catalyzed by Manganese Porphyrin under Mild Conditions

“…The selective oxidation of alcohols to carbonyl compounds is one of the most important processes because the products are valuable in organic synthesis . Numerous methods for oxidation of alcohols have been developed involving the use of stochiometric oxidants such as chromium oxides, TBHP ( tert ‐butyl hydrogen peroxide), hydrogen peroxide, etc ., which cause environmental and high cost problems. From the viewpoints of enviroment and cost, selective oxidation of alcohols with molecular oxygen is extremely valuable and particularly attractive.…”

Synthesis of and Metal Complexation with a Chiral Cyclam

“…This particular feature of these ligands led to the investigation of their utility in transition-metal-catalyzed processes. The Kochi and Burrows laboratories have separately evaluated these macrocyclic amines as ligands for nickel-mediated oxygen transfer processes. − Additionally, these ligands have been applied to zirconium-catalyzed hydroamination, manganese- and iron-catalyzed oxidation, and electrochemical catalytic CO 2 reduction. − Furthermore, the metal complexes of these polyamines have found applications as MRI contrast agents and radiopharmaceuticals …”