Mechanistic Study of the Phase-Transfer-Catalyzed Reduction of Nitrobenzene to Aniline by Iron Carbonyl Complexes. Role of the Radical Anion [Fe3(CO)11]•-

Ragaini, Fabio

doi:10.1021/om950948f

Cited by 30 publications

(22 citation statements)

References 42 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…As far as the activation of nitroarenes by transition metal carbonyl complexes is concerned, the initial step of the reaction has been shown to involve a single electron transfer from the metal to the nitroarene in all the cases in which it has been investigated. These include the use of nickel, [9] ruthenium, [10][11] iron, [12][13][14][15] and rhodium [16][17][18] complexes. No direct evidence for a single electron transfer has been reported in the case of palladium complexes, the metal most widely employed as catalysts, but evidence for radical formation in the activation of nitrosoarenes has been obtained.…”

Section: Mode Of Activation Of the Nitro Groupmentioning

confidence: 99%

Transition Metal Catalyzed Reductive Cyclization Reactions of Nitroarenes and Nitroalkenes

2019

Self Cite

View full text Add to dashboard Cite

Nitroarenes are the entry point for the production of most nitrogen‐containing aromatic compounds. Thus, any transformation that leads directly from them to the final product allows saving one or more synthetic steps. This review deals with homogeneously catalyzed reactions leading to the formation of N‐heterocyclic compounds from nitroarenes or nitroalkenes in one pot. Reactions that lead to the intermediate formation of amines are not considered. Carbon monoxide is the most often employed reductant because it allows selective reactions, is cheap, and only produces CO2 as stoichiometric byproduct. However, the difficulty in handling pressurized CO has stimulated in recent years the development of CO‐surrogates, that is molecules able to liberate CO during the reaction. The use of phosphines and diols has also been developed in conjunction with molybdenum catalysts. The review focusses in more detail on the literature in the period 2006–2018, but reference to earlier work is made when necessary to put recent results in a more general context.

show abstract

Section: Mode Of Activation Of the Nitro Groupmentioning

confidence: 99%

Transition Metal Catalyzed Reductive Cyclization Reactions of Nitroarenes and Nitroalkenes

2019

Self Cite

View full text Add to dashboard Cite

show abstract

“…Compound 3b was obtained by reduction of the corresponding nitrocarbamate by Fe 3 (CO) 12 , following our modification [37] of the procedure originally reported by Alper and coworkers. [38] This procedure is very selective and quite convenient on the laboratory scale [Eq.…”

Section: ð4þmentioning

confidence: 99%

Carbonylation of Dinitrotoluene to Dimethyl Toluenedicarbamate; High Efficiency of Phosphorus Acids as Promoters for the Palladium-Phenanthroline Catalytic System

Gasperini

Ragaini

Cazzaniga

et al. 2005

Advanced Synthesis & Catalysis

Self Cite

View full text Add to dashboard Cite

Phosphorus acids are excellent promoters for the palladium-phenanthroline catalyzed carbonylation of 2,4-dinitrotoluene to 2,4-toluenedicarbamate. For the first time, all intermediate nitrocarbamates and aminocarbamates have been independently synthesized and their amount after every catalytic reaction precisely quantified. An extensive optimization of all experimental variables has been carried out. The best acids are phenylphosphonic and 4-tolylphosphonic acids. The addition of 2,2-dimethoxypropane as an internal drying agent is highly beneficial. The addition of an amine derived from the starting dinitroarene increases both rate and selectivity of the carbonylation reaction. have been prepared for the first time. The latter displays a markedly higher solubility than all other [Pd(Phen) 2 ] 2 þ complexes. The effect of several possible promoters has also been investigated. Under the optimized experimental conditions, a 77.6% selectivity in dicarbamate was obtained when working at a molar ratio dinitrotoluene/Pd ¼ 2920. At the end of the reaction, the dicarbamate spontaneously precipitates out of the solution in high yields upon cooling, with no inclusion of the acid promoter or of phenanthroline. 2,6-Dinitrotoluene can also be efficiently carbonylated to the corresponding dicarbamate.

show abstract

“…Nitro group in aromatic compounds can be reduced to aniline derivatives using iron carbonyl complexes. [16] Moreover, the nitro group can be reduced to form N-containing heterocyclic compounds in the presence of Fe, [17] Pd(TMB) 2 /TMPhen, and Ru 3 (CO) 12 /BIAN. [18] There are also few reports in the literature using substrates bearing -NO 2 functional group for benzimidazole formation in which reduction of the nitro group takes place under variety of catalytic systems such as selenium under basic conditions, [19] Ru 3 (CO) 12 , [20] and phosphines or phosphites (Ph 3 P, DPPE, P(OEt) 3 ).…”

Section: Resultsmentioning

confidence: 99%

“…However, in case of o-nitroaniline, the presence of different reducing agents in the reaction mixture such as Fe(CO) 5 , released CO, Pd(0) and also P(III) are responsible for the reduction of nitro group to the intermediate V which is in accordance with literature. [16,18,21] After that, the ring closure of this intermediate takes place to produce species (VI). In the presence of the produced iron oxides form Fe(CO) 5 , dehydrogenation of species (VI) takes place to deliver the desired benzimidazole.…”

Section: Resultsmentioning

confidence: 99%

Pd‐Catalyzed Reductive Carbonylation‐Ring Closure of Aryl Halides: A Direct Approach for Synthesis of Benzimidazoles

2016

View full text Add to dashboard Cite

A novel protocol is reported for the facile one-pot benzimidazole derivatives formation from Pd-catalyzed reaction of aryl halides (X = I, Br, -Cl), Fe(CO) 5 , and o-diaminobenzene or o-nitroaniline. Aryl halides are first converted to aryl aldehydes using Fe(CO) 5 which then undergo ring closure with o-diaminobenzene or o-nitroaniline in DMF at 110 8C under Ar. In the case of o-nitroaniline, the reduction of the nitro group takes place before the cyclization step in the presence of reducing agents such as Fe(CO) 5 , released CO, Pd(0) and also P(III) in the reaction mixture. There is no need for employing P(III) ligand in case of aryl iodides while P(III) ligand is necessary for aryl bromides and chlorides to facilitate the reaction. In this reaction, Fe(CO) 5 is not only responsible as the CO source and reduction of -NO 2 functionality in o-nitroaniline, but also produces iron oxides residue in the reaction which are responsible for the dehydrogenation step.

show abstract

Mechanistic Study of the Phase-Transfer-Catalyzed Reduction of Nitrobenzene to Aniline by Iron Carbonyl Complexes. Role of the Radical Anion [Fe₃(CO)₁₁]^•-

Cited by 30 publications

References 42 publications

Transition Metal Catalyzed Reductive Cyclization Reactions of Nitroarenes and Nitroalkenes

Transition Metal Catalyzed Reductive Cyclization Reactions of Nitroarenes and Nitroalkenes

Carbonylation of Dinitrotoluene to Dimethyl Toluenedicarbamate; High Efficiency of Phosphorus Acids as Promoters for the Palladium-Phenanthroline Catalytic System

Pd‐Catalyzed Reductive Carbonylation‐Ring Closure of Aryl Halides: A Direct Approach for Synthesis of Benzimidazoles

Contact Info

Product

Resources

About