Anchoring of a Copper(II)–Schiff Base Complex onto Silica-Coated Ferrite Nanoparticles: A Magnetically Separable Catalyst for Oxidative C–O Coupling by Direct C(sp2)–H and C(sp3)–H Bond Activation
摘要:
A novel catalyst consisting of a Schiff base-copper complex on surface-modified silica-coated ferrite nanoparticles was been prepared and used for oxidative C-O cross-coupling reactions of 1,3-dicarbonyl compounds with formamides for the synthesis of enol carbamates. The new catalyst has also been used for esterification of alkylbenzenes with cyclic ethers.
Cyclic ethers to esters and monoesters to bis-esters with unconventional coupling partners under metal free conditions via sp<sup>3</sup> C–H functionalisation
作者:Ganesh Majji、Srimanta Guin、Saroj K. Rout、Ahalya Behera、Bhisma K. Patel
DOI:10.1039/c4cc05050a
日期:——
An efficient metal free oxidative esterification of sp(3) C-H bonds (adjacent to an oxygen atom) in simple solvents like 1,4-dioxane, tetrahydropyran, tetrahydrofuran and ethyl acetate has been achieved using terminal aryl alkenes and alkynes as the ArCOO(-) sources.
Copper-Catalyzed Esterification of Alkylbenzenes with Cyclic Ethers and Cycloalkanes via C(sp<sup>3</sup>)–H Activation Following Cross-Dehydrogenative Coupling
作者:Saroj Kumar Rout、Srimanta Guin、Wajid Ali、Anupal Gogoi、Bhisma K. Patel
DOI:10.1021/ol5011906
日期:2014.6.6
A copper-catalyzed cross-dehydrogenative coupling strategy has been developed for the synthesis of two classes of esters from simple solvents. The reaction of methylarenes with cyclic ethers resulted in alpha-acyloxy ethers involving four sp(3) C-H cleavages, while treatment of methylarenes with cycloalkanes led to the formation of allyl esters at the expense of six consecutive sp(3) C-H bonds.
Generation of bis-Acyl Ketals from Esters and Benzyl Amines Under Oxidative Conditions
作者:Ganesh Majji、Suresh Rajamanickam、Nilufa Khatun、Sourav Kumar Santra、Bhisma K. Patel
DOI:10.1021/jo502903d
日期:2015.4.3
Treatment of benzylamines with esters at an elevated temperature are expected to give amides. However, in the presence of TBAI/TBHP, esters possessing a methylene carbon alpha-to oxygen with benzylamines provide bis-esters rather than the expected amides. Benzylamines under oxidative conditions generate less nucleophilic carboxylates, which couples at the sp(3) C-H bonds of esters and cyclic ethers to give bis-acyl ketals and alpha-acyloxy ethers, respectively.