Silica gel mediated oxidative C–O coupling of β-dicarbonyl compounds with malonyl peroxides in solvent-free conditions

Abstract

For the first time silica gel was observed to activate peroxides in oxidative coupling reactions. Here we report silica gel mediated oxidative C-O coupling of β-dicarbonyl compounds with cyclic diacyl peroxides affording α-acyloxy derivatives with 100 % atom efficiency. The highest yields of coupling products were achieved in solvent free conditions. C-O coupling products were prepared in yields up to 86 %.

A greatly improved procedure for the synthesis of an antibiotic-drug candidate 2,4-diacetylphloroglucinol over silica sulphuric acid catalyst: multivariate optimisation and environmental assessment protocol comparison by metrics

“…It is worth mentioning that silica gel itself has been used as a catalyst in various types of organic reactions through the silanol group as an active site. 52,53 Thereby, the presence of two different active sites could possibly improve the collision frequency between the substrates and the catalytic sites of the SSA catalyst.…”

Device for online monitoring of insulation faults in high-voltage switchgears

“…Among insulation faults, 79% were caused by flashover. [3][4][5] There are strict requirements for the insulation characteristics of high-voltage electrical equipment; however, insulator defects such as impurities, spikes, and bubble gaps can be introduced due to the production process or material limitations. The strong electric field generated due to high voltage cannot get uniformly distributed in this insulator.…”

Electrochemically Induced Intermolecular Cross-Dehydrogenative C–O Coupling of β-Diketones and β-Ketoesters with Carboxylic Acids

“…Similar transformations with stoichiometric amounts of chemical oxidants were performed using hypervalent iodine compounds, − Bu 4 NI/ t -BuOOH, , manganese­(III) acetate, , lead­(IV) acetate, and iron­(III) salts . Benzoyloxylation of the β-dicarbonyl compounds by benzoyl peroxide is based on their preliminary transformation into enamines, − copper complexes, or enolates. − Methods for the intermolecular oxidative acyloxy-functionalization of β-dicarbonyl compounds by diacyl peroxides have been discovered. − Concerning electrochemical intermolecular acetoxylation, it was found that anodic oxidation of enol acetates led to α-acetoxycarbonyl compounds. , …”