Organic & Hybrid Photonic Crystals for Controlling Light-Matter Interaction Processes

Organic & Hybrid Photonic Crystals for Controlling Light-Matter Interaction Processe

Recent Advances of the Oxidation of C-H Bonds to Ketones

The ketones are important intermediates for the synthesis of fine chemicals, such as pharmaceuticals, natural products, agricultural chemicals, dyes, etc. The oxidation of C-H bonds is one of the most direct and efficient synthetic methods for the preparation of ketones. In this review, the oxidation of C-H bonds to ketones is reviewed

Direct oxidation of the C-sp3-H bonds of N-heterocyclic compounds to give the corresponding ketones using a reusable heterogeneous MnOx-N@C catalyst

Novel reusable MnO,-N@C catalyst has been developed for the direct oxidation of N-heterocycles under solvent-free conditions using TBHP as benign oxidant to give the corresponding N-heterocyclic ketones. The catalytic system exhibited a broad substrate scope and excellent regioselectivity, as well as being amenable to gram-scale synthesis. This MnOx-N@C catalyst also showed good reusability and was successfully recycled six times without any significant loss of activity. (C) 2016, Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by Elsevier B.V. All rights reserved

Synergistic H₄NI–AcOH Catalyzed Oxidation of the C_sp³–H Bonds of Benzylpyridines with Molecular Oxygen

The oxidation of benzylpyridines forming benzoylpyridines was achieved based on a synergistic H₄NI–AcOH catalyst and molecular oxygen in high yield under solvent-free conditions. This is the first nonmetallic catalytic system for this oxidation transformation using molecular oxygen as the oxidant. The catalytic system has a wide scope of substrates and excellent chemoselectivity, and this procedure can also be scaled up. The study of a preliminary reaction mechanism demonstrated that the oxidation of the C_sp³–H bonds of benzylpyridines was promoted by the pyridinium salts formed by AcOH and benzylpyridines. The synergistic effect of H₄NI–AcOH was also demonstrated by control experiments

An Effective Method for the Construction of Esters Using Cs₂CO₃ as Oxygen Source

An effective method for the construction of esters from acyl chloride and halohydrocarbon using Cs₂CO₃ as an oxygen source was achieved for the first time. The methodology has a wide scope of substrates and can be scaled up. The study of a preliminary reaction mechanism demonstrated that the O in the products comes from Cs₂CO₃ and this esterification proceeds through a free radical reaction. It was also found that CO₂ can also be used in this esterification reaction as an oxygen source

Iron/ABNO-Catalyzed Aerobic Oxidation of Alcohols to Aldehydes and Ketones under Ambient Atmosphere

We report a new Fe­(NO₃)₃·9H₂O/9-azabicyclo­[3.3.1]­nonan-<i>N</i>-oxyl catalyst system that enables efficient aerobic oxidation of a broad range of primary and secondary alcohols to the corresponding aldehydes and ketones at room temperature with ambient air as the oxidant. The catalyst system exhibits excellent activity and selectivity for primary aliphatic alcohol oxidation. This procedure can also be scaled up. Kinetic analysis demonstrates that C–H bond cleavage is the rate-determining step and that cationic species are involved in the reaction

oxygenationofbenzylicetherstoestersusingmnoxnccatalyst

A catalytic system for the oxidation of benzylic ethers to esters has been developed utilizing reusable MnO_x-N@C as catalyst and tert-butyl hydroperoxide(TBHP) as benign oxidant under neat condition. The catalytic oxidation system has good functional groups tolerance and excellent chemoselectivity, and this catalytic procedure can also be scaled up

Asymmetric Epoxidation of Olefins with Hydrogen Peroxide by an in Situ-Formed Manganese Complex

Asymmetric epoxidation of a variety of cis, trans, terminal, and trisubstituted olefins in excellent yields (up to 94%) and enantioselectivities (>99% ee) by an in situ-formed manganese complex using H₂O₂ has been developed. A relationship between the hydrophobicity of the catalyst imposed by ligand and the catalytic activity has been observed. The influence of the amount and identity of the acid additive was examined, and improved enantioselectivities were achieved through the use of a catalytic amount of a carboxylic acid additive