Oxidation Of Diarylmethanes Research Articles

Transition-Metal-Free C(sp³)⁻H Oxidation of Diarylmethanes.

An efficient direct C(sp3)–H oxidation of diarylmethanes has been demonstrated by this study. This method employs environment-friendly O2 as an oxidant and is promoted by commercially available MN(SiMe3)2 [M = K, Na or Li], which provides a facile method for the synthesis of various diaryl ketones in excellent yields. This protocol is metal-free, mild and compatible with a number of functional groups on substrates.

Inside Back Cover: Cu(II)‐Catalyzed Ligand‐Free Oxidation of Diarylmethanes and Second Alcohols in Water (Chin. J. Chem. 9/2017)

The inside back cover picture shows a simple and efficient Cu(II)‐catalyzed ligand‐free oxidation of diarylmethanes and secondary alcohols using 70% TBHP in water. A series of diarylmethanes were directly oxidized into diaryl ketones in 67%–98% yields. Additionally, various secondary alcohols were also transformed into the desired products in 48%–98% yields. Importantly, the catalytic system in the absence of any organic solvent, surfactant, or phase transfer agent, had a wide substrate scope and a high tolerance for various functional groups. More details are discussed in the article by Liu et al. on page 1391–1395. image

Cu(II)‐Catalyzed Ligand‐Free Oxidation of Diarylmethanes and Second Alcohols in Water

We developed a simple and efficient Cu(II)‐catalyzed ligand‐free oxidation of diarylmethanes and secondary alcohols using 70% tert‐butyl hydroperoxide (TBHP) in water. A series of diarylmethanes were directly oxidized into diaryl ketones in 67%–98% yields. Additionally, various secondary alcohols were also transformed into the desired products in 48%–98% yields. Importantly, the catalytic system in the absence of any organic solvent, surfactant, or phase transfer agent, had a wide substrate scope and a high tolerance for various functional groups.

Dynamics of the transient species generated upon photolysis of diarylmethanes within zeolites — Deprotonation and oxidation reactions

The oxidation of diarylmethanes is a multistep process involving initial formation of a radical cation, deprotonation of the radical cation to the radical, and oxidation of the radical to the carbocation. The dynamics and efficiency of the last two steps in this process, namely deprotonation and oxidation, in acidic zeolites and non-acid zeolites are examined in the present work as a function of the acidity of the diarylmethane radical cations and the oxidation potential of the diarylmethyl radicals. Our results indicate that rate constants for deprotonation strongly depend on the acidity of the radical cations, but not on the composition of the zeolites. In addition, oxidation of the radicals to the diarylmethyl cations is strongly dependent on both the oxidation potential of the radicals and the oxidizing ability of the zeolite. This dependence allows oxidation potentials of the zeolites to be estimated.Key words: radical cations, carbocations, zeolites, laser flash photolysis.

Oxidation by Solids. II. The Preparation of Either Tetraarylethanes or Diaryl Ketones by the Oxidation of Diarylmethanes with Manganese Dioxide

Oxidation by Solids. II. The Preparation of Either Tetraarylethanes or Diaryl Ketones by the Oxidation of Diarylmethanes with Manganese Dioxide