Reductive Carbonylation Of Nitroarenes Research Articles

Reductive Carbonylation of Nitroarenes Using a Heterogenized Phen-Pd Catalyst.

The reductive carbonylation of nitroarenes in the presence of MeOH and CO(g) is one of the interesting alternative routes without utilizing toxic phosgene and corrosive HCl generation for the synthesis of industrially useful carbamate compounds that serve as important intermediates for polyurethane production. Since homogeneous palladium catalysts supported by phen (phen = 1,10-phenanthroline) are known to be effective for this catalysis, the heterogenized Pd catalyst was developed using the phen-containing solid support. In this study, we report the synthesis of a phen-based heterogeneous Pd catalyst, Pd@phen-POP, which involves the solvent knitting of a phen scaffold via the Lewis-acid-catalyzed Friedel-Crafts reaction using dichloromethane as a source for linker in the presence of AlCl3 as a catalyst. The resulting solid material has been thoroughly characterized by various physical methods revealing high porosity and surface area. Similar to the homogeneous pallidum catalyst, this heterogeneous catalyst shows efficient reductive carbonylation of various nitroarenes. The catalytic reaction using nitrobenzene as a model compound presents a high turnover number (TON = 530) and a reasonable turnover frequency (TOF = 45 h-1), with a high selectivity (92%) for the carbamate formation. According to the recycling study, the heterogeneous catalyst is recyclable and retains ∼90% of the original reactivity in each cycle.

Experimental and theoretical electron density of intermediates in palladium-phenanthroline catalyzed carbonylation of amines and reductive carbonylation of nitroarenes.

The accurate electron density distribution in Pd(Neoc)Cl2 (CO) (Neoc = 2,9-dimethyl-1,10-phenanthroline) was measured and calculated to investigate the chemical bonding features, the electrostatic forces and the polarizable bonds in this complex, which is a prototype of the proposed intermediate in the catalytic carbonylation of amines and nitroarenes. The quantum theory of atoms in molecules enables to investigate the nature of the elusive fifth coordination in the complex, which is approximately intermediate between a bypiramid penta-coordination and a square planar tetra-coordination. The analysis of the electrostatic potential and of the distributed atomic polarizabilities enables to address the sites that are more prompt to react, in particular in the context of the catalytic cycle. © 2017 Wiley Periodicals, Inc.

ChemInform Abstract: Away from Phosgene: Reductive Carbonylation of Nitroarenes and Oxidative Carbonylation of Amines, Understanding the Mechanism to Improve Performance

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Fine Chemicals by Reductive Carbonylation of Nitroarenes, Catalyzed by Transition‐Metal Complexes

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.

Fine Chemicals by Reductive Carbonylation of Nitroarenes, Catalyzed by Transition Metal Complexes

Fine Chemicals by Reductive Carbonylation of Nitroarenes, Catalyzed by Transition Metal Complexes

Palladium nitrosoarene complexes in reductive carbonylation of nitroarenes

The reactions of carbon monoxide with the palladium nitrosoarene complexes Pd2(μ-OCOR)2(—CH2C6H4NO)2 (1, R = Me, CF3, But, or Ph) and Pd2(μ-OCOR)2(PhNC6H4NO)2 (2, R = Me, CF3, But, or Ph) were studied. Complexes 1 contain the o-nitrosotoluene molecule metallated at the methyl group. In complexes 2, the phenyl-o-nitrosophenylamide ligand coordinated via two nitrogen atoms can be considered as a nitrosobenzene derivative bearing the NPh group in the ortho position of the Ph ring. It all cases, carbonylation of the complexes afforded the corresponding aryl isocyanates Ar—N=C=O or the products of their further transformations. The mechanism of reductive carbonylation of nitroarenes catalyzed by palladium compounds and the role of palladium nitrosoarene complexes as possible intermediates in this process are discussed.

Investigation of the possible role of arylamine formation in the ortho-substituted nitroarenes reductive cyclization reactions to afford heterocycles

Reductive carbonylation of nitroarenes with an unsaturated group in the ortho position generally affords high yields of heterocyclic compounds, including indoles, chalcones, quinolines, benzimidazoles, benzotriazoles, and indazoles. There is, however, no direct information on the organic intermediates formed during the reaction. In this paper, we have examined the possible formation of anilines as intermediates in the synthesis of indoles, acylindoles, quinolines, and quinolones with several catalytic systems based on palladium, ruthenium and rhodium. It transpired that, independent of the metal complex used as a catalyst, the formation of aniline as an intermediate is essential in the intra-molecular condensation reactions of nitroarenes involving an aldehydic or a keto group (including Michael addition reactions), but plays at best a very limited role in the addition reactions involving a CC double bond.

ChemInform Abstract: Novel Catalytic Reactions Using Ruthenium and Platinum Complexes

The following novel organic syntheses catalyzed by ruthenium (1-7) and platinum complexes (8-9) which have been disclosed by the authors are reviewed. 1) Activation of alcohols which provides novel synthetic methods for alkylamines and N-heterocycles such as piperidines, pyrrolidines, quinolines and indoles. 2) Hydroamidation of olefins. 3) Addition of carboxylic amides to olefins. 4) Addition of aldehydes to olefins to give unsymmetric ketones. The reactions 3) and 4) involve the activation of carbon-hydrogen bond of formyl groups. 5) [2 + 2] Cross cycloaddition of norbornenes with acetylene which provides the synthetic tool for linear polycyclo compounds. 6) Linear codimerization of acetylenes with 1, 3-dienes. 7) Addition of carboxylic acids to acetylenes to give enol esters. 8) Reductive carbonylation of nitroarenes to amides, urethanes and ureas. 9) Thermal and photo-chemical carbonylation of alkyl iodides to esters or aldehydes. Even alkyl halides with β-hydrogens are efficiently carbonylated. The mechanisms of these novel reactions are suggested.

ChemInform Abstract: DIRECT SYNTHESIS OF N‐ARYL BENZAMIDES BY REDUCTIVE CARBONYLATION OF NITROARENES CATALYZED BY RHODIUM CARBONYLS IN BENZENE

AbstractDie Nitrobenzole (I) werden in Gegenwart von Benzol, Kohlenmonoxid und Rhodiumcarbonyl‐Katalysatoren wie (II) in die Amide (III), die Amine (IV) und in manchen Fällen zusätzlich in die Diarylharnstoffe (V) übergeführt.

DIRECT SYNTHESIS OF N-ARYL BENZAMIDES BY REDUCTIVE CARBONYLATION OF NITROARENES CATALYZED BY RHODIUM CARBONYLS IN BENZENE

Abstract The reactions of nitroarenes, carbon monoxide, and benzene in the presence of Rh4(CO)12 or Rh6(CO)16 give N-aryl benzamides via the reductive carbonylation of nitroarenes and subsequent addition of benzene to the resulting aryl isocyanates.