Oxidative Amide Coupling from Functionally Diverse Alcohols and Amines Using Aerobic Copper/Nitroxyl Catalysis

Protocol for the preparation of amorphous manganese oxide and its application as heterogeneous catalyst in the direct synthesis of amides and nitriles

The cleavage and functionalization of carbon-carbon (C–C) bonds has emerged as a powerful tool for preparing value-added chemicals. In this protocol, we describe the preparation of amorphous manganese oxide and its application as a heterogeneous catalyst in the direct synthesis of amides via successive cleavage and amidation of C–C bonds in alcohols. Furthermore, we describe how a slight modification of reaction conditions allows for the cleavage and cyanation of alcohols to access sterically hindered nitriles.

For complete details on the use and execution of this protocol, please refer to He et al. (2022).

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Heterogeneous MnO_x-catalyzed cleavage and amidation/cyanation of alcohols

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Convenient preparation of MnO_x in large scale

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Recycling and reusing of MnO_x

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Wide substrate scope and gram-scale synthesis allowable

Publisher’s note: Undertaking any experimental protocol requires adherence to local institutional guidelines for laboratory safety and ethics.

Efficient Aerobic Oxidation of Organic Molecules by Multistep Electron Transfer

This Minireview presents recent important homogenous aerobic oxidative reactions which are assisted by electron transfer mediators (ETMs). Compared with direct oxidation by molecular oxygen (O₂), the use of a coupled catalyst system with ETMs leads to a lower overall energy barrier via stepwise electron transfer. This cooperative catalytic process significantly facilitates the transport of electrons from the reduced form of the substrate‐selective redox catalyst (SSRC^red) to O₂, thereby increasing the efficiency of the aerobic oxidation. In this Minireview, we have summarized the advances accomplished in recent years in transition‐metal‐catalyzed as well as metal‐free aerobic oxidations of organic molecules in the presence of ETMs. In addition, the recent progress of photochemical and electrochemical oxidative functionalization using ETMs and O₂ as the terminal oxidant is also highlighted. Furthermore, the mechanisms of these transformations are showcased.

Copper-Catalyzed Formylation of Amines by using Methanol as the C1 Source

Cu/TEMPO catalyst systems are known for the selective transformation of alcohols to aldehydes, as well as for the simultaneous coupling of alcohols and amines to imines under oxidative conditions. In this study, such a Cu/TEMPO catalyst system is found to catalyze the N-formylation of a variety of amines by initial oxidative activation of methanol as the carbonyl source via formaldehyde and formation of N,O-hemiacetals and oxidation of the latter under very mild conditions. A vast range of amines, including aromatic and aliphatic, primary and secondary, and linear and cyclic amines are formylated under these conditions with good to excellent yields. Moreover, paraformaldehyde can be used instead of methanol for the N-formylation.