Copper-catalyzed methyl esterification of aromatic aldehydes and benzoic alcohols by TBHP as both oxidant and methyl source

Application of the Wittig Rearrangement of N-Butyl-2-benzyloxybenzamides to Synthesis of Phthalide Natural Products and 3-Aryl-3-benzyloxyisoindolinone Anticancer Agents

Application of the [1,2]-Wittig rearrangement and cyclisation approach to 3-arylphthalides has been evaluated for the synthesis of three bioactive natural products. While this is successful in the case of crycolide, providing the second synthesis of this compound, the more sterically demanding targets isopestacin and cryphonectric acid prove not to be amenable to this approach, with the 2,6-disubstituted aryl groups causing the failure of the rearrangement and alkylation steps, respectively. Direct oxidation of the substituted benzhydrols resulting from [1,2]-Wittig rearrangement using MnO2 provides a new route to 3-aryl-3-hydroxyisoindolinones, and this method has been used in the synthesis of two 3-aryl-3-benzyloxyisoindolinone anticancer agents.

Direct access to pyrrole anhydrides via oxidative self-coupling of pyrrole carboxaldehydes

An elegant synthesis of pyrrole-2-carboxylic acid anhydrides from pyrrole-2-carboxaldehydes using TBAI as a catalyst and tert-butyl hydroperoxide (TBHP) as an oxidant is described herein. Unlike the previous reports wherein pyrrole-2-carboxylic acids were invariably used, we report here for first time the oxidative self-coupling of N-benzyl pyrrole-2-carboxaldehydes for the synthesis of 1-benzyl-1H-pyrrole-2-carboxylic anhydrides. In addition, a one-pot synthesis of novel pyrrole-2-carboxamides from pyrrole-2-carboxaldehydes is also reported. The mechanistic investigation supports a previously unexplored oxidative self-coupling of a pyrrole acyl radical, leading to the synthesis of a carboxylic anhydride.

Copper(ii) and iron(iii) complexes with arylhydrazone of ethyl 2-cyanoacetate or formazan ligands as catalysts for oxidation of alcohols

Cooperative coordination and ionic interactions assisted E/Z isomerization of arylhydrazone ligands lead to a variety of Cu^II complexes, which effectively catalyse the homogeneous oxidation of alcohols to carbonyl compounds.

Copper-catalyzed radical methylation/C-H amination/oxidation cascade for the synthesis of quinazolinones

A copper-catalyzed radical methylation/sp(3) C-H amination/oxidation reaction for the facile synthesis of quinazolinone was developed. In this cascade reaction, dicumyl peroxide acts not only as a useful oxidant but also as an efficient methyl source. Notably, a methyl radical, generated from peroxide, was confirmed by electron paramagnetic resonance for the first time.

Ultrasound assisted direct oxidative esterification of aldehydes and alcohols using graphite oxide and Oxone

A sonochemical procedure for direct oxidative esterification of aldehydes and alcohols using graphite oxide and Oxone in an alcoholic solvent is described. Mild reaction conditions, short reaction times, cost-effectiveness, and facile isolation of the products make the present system as a practical method.

Metal-free regioselective C-3 nitration of quinoline N-oxides with tert-butyl nitrite

A direct, regioselective and eco-friendly C3-nitration of quinoline N-oxides using tert-butyl nitrite as both the nitro source and oxidant has been developed. This reaction undergoes a free radical process and can be smoothly scaled up to gram scale.

The cascade synthesis of quinazolinones and quinazolines using an α-MnO2 catalyst and tert-butyl hydroperoxide (TBHP) as an oxidant

Heterogeneously catalyzed synthesis of quinazolinones or quinazolines is reported in this study.

Nitrogen enriched mesoporous organic polymer anchored copper(ii) material: an efficient and reusable catalyst for the synthesis of esters and amides from aromatic systems

New mesoporous polymer anchored copper acetate (Cu-mPMF) has been synthesized and well characterized. The catalytic performance of this complex has been tested for the synthesis of esters and amides.

Copper-catalyzed oxidative esterification of unactivated C(sp3)–H bonds with carboxylic acids via cross dehydrogenative coupling

An effective copper-catalyzed esterification of unactivated (non-benzylic and allylic) C(sp³)–H bonds of hydrocarbons with Selectfluor as an oxidant has been developed.

Magnetic Co3O4/reduced graphene oxide nanocomposite as a superior heterogeneous catalyst for one-pot oxidative esterification of aldehydes to methyl esters

Magnetic Co₃O₄/reduced graphene oxide nanocomposite as a superior heterogeneous catalyst for one-pot oxidative esterification of aldehydes to methyl esters.

Copper-catalyzed acyloxylation of the C(sp3)–H bond adjacent to an oxygen by a cross-dehydrogenative coupling approach

We demonstrated a dehydrogenative cross coupling between a benzyl alcohol and C(sp³)–H bond for the construction of a C–O bond. This method reveals a new strategy for the direct use of benzyl alcohols in the synthesis of esters with the use of copper as a catalyst and TBHP as an oxidant.