The possibility of developing new methods for the efficient construction organic molecules via disconnections other than traditional functional group transformations has driven interest in direct functionalization C-H bonds. ubiquity bonds makes such attractive, but they also pose several challenges. first is reactivity and selectivity To achieve this, directing groups (DGs) are often installed that can enhance effective concentration catalyst, leading to thermodynamically stable...

A methodology for the high yield and facile synthesis of isoquinolones from benzamides alkynes via oxidative ortho C−H activation has been developed. Ag2CO3 proved to be an optimal oxidant when MeCN was used as a solvent, [RhCp*Cl2]2 utilized efficient catalyst. Both N-alkyl N-aryl secondary can applied effective substrates. Furthermore, primary react with two alkyne units, leading tricyclic products double coupling. The reactivity structurally related 1-hydroxyisoquinoline also...

Rh(III)-catalyzed oxidative coupling reactions between benzamides or heteroaryl carboxamides and olefins have been developed. The vinylation product can further undergo a Michael reaction leading to γ-lactam in the case of electron-withdrawing olefins.

Cationic half-sandwich scandium alkyl complexes bearing monocyclopentadienyl ligands embedded in chiral binaphthyl backbones act as excellent catalysts for the enantioselective C-H bond addition of pyridines to various 1-alkenes, leading formation a variety enantioenriched alkylated pyridine derivatives high yields and enantioselectivity (up 98:2 er).

Lignin represents the most abundant source of renewable aromatic resources, and depolymerization lignin has been identified as a prominent challenge to produce low-molecular-mass chemicals. Herein, we report nanostructured MoOx/CNT, which can serve an efficient catalyst in hydrogenolysis enzymatic mild acidolysis lignins (EMALs) derived from various lignocellulosic biomass, thus giving monomeric phenols high yields (up 47 wt %). This showed selectivity toward phenolic compounds having...

A fundamental understanding of lignin solubilization offers structural information that would benefit a variety value added applications.

This review summarizes the recent advances in fabrication strategies and versatile applications of lignin-derived biodegradable film materials from viewpoint sustainable development.

Abstract C-lignin is a homo-biopolymer, being made up of caffeyl alcohol exclusively. There significant interest in developing efficient and selective catalyst for depolymerization C-lignin, as it represents an ideal feedstock producing catechol derivatives. Here we report atomically dispersed Ru catalyst, which can serve the hydrogenolysis via cleavage C−O bonds benzodioxane linkages, giving catechols high yields with TONs to 345. A unique selectivity propenylcatechol (77%) obtained,...

Producing monomeric phenols from lignin biopolymer depolymerization in a detachable and efficient manner comes under the spotlight on fullest utilization of sustainable lignocellulosic biomass. Here, we report low-loaded highly dispersed Ru anchored chitosan-derived N-doped carbon catalyst (RuN/ZnO/C), which exhibits outstanding performance reductive catalytic fractionation lignocellulose. Nearly theoretical maximum yields phenolic monomers are achieved, corresponding to TON as 431 mol

[RhCp*Cl2]2 (1−2 mol %) can catalyze the oxidative coupling of N-aryl-2-aminopyridines with alkynes and arylates to give N-(2-pyridyl)indoles N-(2-pyridyl)quinolones, respectively, using Cu(OAc)2 as an oxidant. Coupling styrenes gave mono- and/or disubstituted olefination products.

ADVERTISEMENT RETURN TO ISSUEPREVLetterNEXTPalladium-Catalyzed Oxidative Cross-Coupling between Pyridine N-Oxides and IndolesXue Gong†‡, Guoyong Song†, Hong Zhang‡, Xingwei Li†View Author Information Dalian Institute of Chemical Physics, Chinese Academy Sciences, 116023, P. R China, School Chemistry, Northeast Normal University, Changchun 130024, R. China[email protected]; [email protected]†Chinese Sciences.‡Northeast University.Cite this: Org. Lett. 2011, 13, 7, 1766–1769Publication Date...

Catalytic oxidative coupling between acrylamides and alkynes was achieved using 0.5 mol % loading of [RhCp*Cl(2)](2) with Cu(OAc)(2) as an oxidant. 2-Pyridones, iminoesters, substituted indoles could be obtained a result the electronic steric effects substituents in acrylamides.

Selective synthesis of quinolines has been achieved via oxidative annulation functionalized pyridines with two alkyne molecules under Rh(III)-catalyzed cascade C–H activation using Cu(OAc)2 as an oxidant. The selectivity this reaction is oxidant-dependent, particularly on the anion

Rhodium and iridium complexes of a new type abnormal N-heterocyclic carbenes (NHCs) derived from imidazo[1,2-a]pyridiniums have been prepared via silver transmetalation, where metalation can be directed to either the C-2 or C-3 position imidazo[1,2-a]pyridine ring provided that other is appropriately blocked. The donating abilities these NHC ligands assessed average CO stretching frequencies their corresponding dicarbonyl complexes. By varying N-alkyl groups fusing pyridine moiety with an...

Heteroatoms enhance polymerization and copolymerization of functional olefins.

Substantial attention has been given to depolymerization of lignin into monomeric phenols in recent years because is a renewable and CO2-netural aromatic resource. Recent results indicated that the base can shift selectivity from C3-fragmented C2-fragmented partially transition metal-catalyzed hydogenolysis, while reaction mechanisms have remained elusive. Using series dimeric, trimeric, polymeric β-O-4 mimics, as well their deuterated analogues, we now report an in-depth experimental study...

Rh(III)-catalyzed oxidative coupling reactions between isoquinolones with 3-aryl groups and activated olefins have been achieved using anhydrous Cu(OAc)(2) as an oxidant to give tetracyclic products. The nitrogen atom acts a directing group facilitate ortho C-H activation. This reaction can be one-pot starting from methyl benzohydroxamates, without the necessity of isolation isoquinolone A broad scope substrates has demonstrated, both terminal internal applied. In N-methylmaleimide,...

The asymmetric C–H annulation of O-pivaloyl 1-indolehydroxamic acid with donor/acceptor diazo compounds has been achieved for the first time, to best our knowledge, by using a rhodium catalyst embedded in chiral binaphthyl backbone. This protocol constitutes straightforward route synthesis new family 1,2-dihydro-3H-imidazo[1,5-a]indol-3-one derivatives having quaternary carbon stereocenter high yields and excellent enantioselectivity (up 98:2 er).

The efficient and selective ortho-alkylation of N,N-dimethyl anilines via C-H addition to alkenes was achieved for the first time using a cationic half-sandwich yttrium catalyst. This protocol constitutes straightforward atom-economical route synthesis new family tertiary aniline derivatives with branched alkyl substituents, which are otherwise difficult obtain. DFT calculation studies suggest that interaction between atom NMe2 group plays an important role intramolecular activation through...

Catechyl lignin (C-lignin), a homobiopolymer usually existing in the seed coats of Vanilla and Cactaceae plants, was recognized as an "ideal lignin" archetype leading to well-defined aromatic compounds. Herein, we report that deep eutectic solvents (DESs) can serve green recyclable extract C-lignin from cheap abundant castor for first time, which led biopolymer good yields with high purity. High abundance benzodioxane structures DES-extracted samples corroborated by HSQC NMR experiments....

Biodegradable composite materials are increasingly imperative in modern society owing to their eco-friendly character, and further reducing costs improving compatibility of composites will facilitate applications.