Reaction Of Nitroalkanes Research Articles

A New General, Mild Preparation of 2-Hydroxy-β-nitrostyrenes Starting from 2-Acetylsalicylaldehydes and Nitroalkanes via Domino Process

AbstractA new practical and improved preparation of 2-hydroxy-β-nitrostyrenes by reaction of nitroalkanes with acetylsalicylaldehydes, promoted by DBU in acetonitrile at 0 °C is reported. Under these conditions products were isolated in very good yields and as single E-diastereomers.

Intermolecular direct catalytic cross-Michael/Michael reactions and tandem Michael/Michael/aldol reactions to linear compounds

Catalytic cross-Michael/Michael reactions of nitroalkenes and ethyl acrylate with pronucleophiles including thiols, dimethyl methylmalonate, and 2-nitropropane to linear three-component products were developed by using a catalytic amount of DBU in DMSO. Tandem sulfa-Michael/Michael/aldol reactions of a thiol, a nitroalkene, ethyl acrylate, and an aldehyde proceeded to give a linear four-component product. The high nucleophilicity of in situ-formed nitronate anions and ester enolates in DMSO was important for the present multi-component cascade reactions using pronucleophiles that had protons with relatively high acidity.

Asimetrik Michael Katılma Tepkimesi için Prolin bazlı β-Hidroksiamit Organokatalizörü

Applications of chiral organocatalysts in reaction types capable of forming C-C bonds, such as Michael addition, are one of the important research areas of recent years. One of the best examples of Michael addition, one of the important works of organic reaction types, is the reaction of nitroolefins with ketones in the presence of organocatalysts. In this study, L-proline-based amide derivative was synthesized with moderate yield and its structure was elucidated by various techniques. As an organocatalyst, its effect on enantiomeric excess (e.e.) was investigated in Michael addition studies and the best enantiomeric excess value was found to be 65% in carbontetra chloride (CCl4).

Catalytic intermolecular aldol reactions of transient amide enolates in domino Michael/aldol reactions of nitroalkanes, acrylamides, and aldehydes

Aldol reactions of amide enolates formed by addition of nitronates to acrylamides proceeded with catalytic amounts of KOH in DMSO.

Nitroalkanes as electrophiles: synthesis of triazole-fused heterocycles with neuroblastoma differentiation activity.

We discovered a reaction of nitroalkanes with 2-hydrazinylquinolines, 2-hydrazinylpyridines and bis-2,4-dihydrazinylpyrimidines in polyphosphoric acid (PPA) affording 1,2,4-triazolo[4,3-a]quinolines, 1,2,4-triazolo[4,3-a]pyridines and bis[1,2,4]triazolo[4,3-a:4',3'-c]pyrimidines, respectively. The reaction expands the scope of heterocyclic annulations involving phosphorylated nitronates, believed to be the electrophilic intermediates formed from nitroalkanes in PPA. Several of the synthesized triazoles showed promising anticancer activity by inducing differentiation in neuroblastoma cancer cells. Due to the urgent need for novel differentiation agents for neuroblastoma therapy, this finding warrants further evaluation of this class of compounds against neuroblastoma.

Comprehension of the α-Arylation of Nitroalkanes

Background: α-Aryl substituted nitroalkanes are important synthetic intermediates for the preparation of pharmaceutical molecules, natural products, and functional materials. Due to their scare existence in Nature, synthesis of these compounds has attracted the attention of synthetic and medicinal chemists, rendering α-arylation of nitroalkanes of an important research topic. This article summarizes the important advances of α- arylation of nitroalkanes since 1963. Results: After a brief introduction of the synthetic application and the reactions of nitroalkanes, this article reviewed the synthetic methods for the α-arylated aliphatic nitro compound. The amount of research on α-arylation of nitroalkanes using various arylation reagents and the discovery of elegant synthetic approaches towards such skeleton have been discussed. This review described these advances in two sections. One is the arylation of non-activated nitroalkanes, with an emphasis on the application of diverse arylation reagents; the other focuses on the arylation of activated nitroalkanes, including dinitroalkanes, trinitroalkanes, α-nitrosulfones, α-nitroesters, α-nitrotoluenes, and α-nitroketones. The synthetic application of these methods has also been presented in some cases. Conclusion: In this review, we described the progress of α-arylation of nitroalkanes. Although the immense amount of research on α-arylation of aliphatic nitro compounds has been achieved, many potential issues still need to be addressed, especially the asymmetric transformation and its wide application in organic synthesis.

N‐Heterocyclic‐Carbene‐Catalyzed Reactions of Nitroalkenes: Synthesizing Important Building Blocks

AbstractThe recent developments of N‐heterocyclic carbene (NHC)‐catalyzed acyl anion equivalent (Stetter reaction), homoenolate, and enolate reactions with reactive nitroalkenes as Michael acceptors are described. The unique strategies for NHC‐catalyzed C−C bond‐forming reactions using nitroalkenes for the synthesis of synthetic building blocks, in particular asymmetric approaches, are systematically presented. Advances in the single‐electron‐transfer reaction combined with the use of NHCs as organocatalysts are also discussed, with nitroalkenes acting as important coupling partners. This Focus Review brings together both the accomplishments and the future work needed in this important area.

Organocatalytic Nitroaldol Reaction Associated with Deuterium‐Labeling

AbstractA deuterium‐labeling reaction of nitroalkanes in deuterium oxide and the subsequent nitroaldol reaction have been accomplished under basic and organocatalytic conditions to provide the deuterium‐labeled β‐nitroalcohols in high yields and high deuterium contents. β‐Deuterated β‐nitroalcohols could be smoothly obtained from the reaction of nitroalkanes and various electrophiles using the easily‐removal basic resin WA30. Furthermore, the asymmetric nitroaldol reaction using nitromethane and α‐keto esters as electrophiles in the presence of a quinine‐derived organocatalyst in deuterium oxide could provide the desired β‐deuterated nitroalcohol derivatives with high enantioselectivities.magnified image

Electrophilically activated nitroalkanes in the synthesis of 6,7-dihydro-1H-cyclopenta[g]perimidines

A highly efficient synthetic route to 6,7-dihydro-1H-cyclopenta[gh]perimidines has been proposed on the basis of a novel reaction of nitroalkanes with 4,5-diaminoacenaphthene in the presence of polyphosphoric acid. The reaction involves phosphorylation of the aci-nitro compound, followed by intramolecular cyclization.

ChemInform Abstract: Chiral Ammonium Aryloxides as Broensted Base Catalysts for the Henry Reaction of Nitroalkanes to Aromatic and Aliphatic Aldehydes.

ChemInform Abstract: Chiral Ammonium Aryloxides as Broensted Base Catalysts for the Henry Reaction of Nitroalkanes to Aromatic and Aliphatic Aldehydes.

Chiral Ammonium Aryloxides as Brønsted Base Catalysts for the Henry Reaction of Nitroalkanes to Aromatic and Aliphatic Aldehydes

An enantioselective organocatalyzed Henry reaction was reported using chiral ammonium aryloxides as Bronsted base organocatalysts. A wide range of aliphatic and aromatic aldehydes along with several nitroalkanes are tolerated providing the corresponding enantioenriched β-nitroalcohols with moderate to high diastereomeric ratios and up to 83 % ee. An inversion of the diastereoselectivity was observed when changing from aromatic to aliphatic aldehydes. Transition state models were proposed in order to account for this phenomenon.

Stereoselective amine-thiourea-catalysed sulfa-Michael/nitroaldol cascade approach to 3,4,5-substituted tetrahydrothiophenes bearing a quaternary stereocenter

An investigation on the stereoselective cascade sulfa-Michael/aldol reaction of nitroalkenes and commercially available 1,4-dithiane-2,5-diol to 3,4,5-substituted tetrahydrothiophenes, bearing a quaternary stereocenter, is presented. A secondary amine thiourea derived from (R,R)-1,2-diphenylethylamine was found to be the most effective catalyst when using trans-β-methyl-β-nitrostyrenes affording the heterocyclic products in good yields and moderate stereoselectivities.

ChemInform Abstract: Copper‐Catalyzed [3 + 2] Cycloaddition/Oxidation Reactions Between Nitro‐Olefins and Organic Azides: Highly Regioselective Synthesis of NO2‐Substituted 1,2,3‐Triazoles.

A new copper-catalyzed [3 + 2] cycloaddition/oxidation reaction of nitro-olefins with organic azides has been developed to afford 1,4(-NO2),5-trisubstituted 1,2,3-triazoles. This reaction sequence has a broad substrate scope and affords NO2-substituted 1,2,3-triazoles with high regioselectivities and in good to excellent yields. The involved oxidative process overcomes the elimination of HNO2 for general cycloaddition of nitro-olefins with organic azides, which shows a high atom economy and potential applications.

Asymmetric Formal [3+2] Cycloaddition Reaction of Succinaldehyde and Nitroalkene Catalyzed by Diphenylprolinol Silyl Ether

AbstractThe enantioselective domino Michael/Henry reaction of nitroalkenes with succinaldehyde was found to proceed efficiently upon using diphenylprolinol silyl ether as the organocatalyst. The reaction affords cis‐disubstituted nitropentenes with excellent diastereoselectivities and enantioselectivities after treatment of the Michael product with Ac2O and pyridine.

ChemInform Abstract: Recent Developments in the Synthesis of Imidazo[1,2‐a]pyridines

AbstractReview: [151 refs.

Morita–Baylis–Hillman Reactions with Nitroalkenes: A Case Study

AbstractWe report on the use of a highly reactive super‐DMAP catalyst in Morita–Baylis–Hillman (MBH) reactions of nitroalkenes with ethyl glyoxylate, which result in excellent conversions and short reaction times with, importantly, very low catalyst loading. An extensive study of this particular reaction is presented, which examines all mechanistic and experimental details. Several critical points were hence uncovered that include the correlation between reaction efficiency and Lewis basicity of the catalyst; the double role played by the promoter, primarily as a nucleophilic activator towards the nitroalkene, and as a Brønsted base that triggers glyoxylate depolymerisation. More generally, the limitations in the choice of electrophiles that can engage efficiently in MBH‐type transformations are rationalized by the competition between a productive pathway and a nitroalkene polymerization process. Other aspects of this transformation, used as a case study, are presented in the light of physical organic chemistry.

Recent Developments in the Synthesis of Imidazo[1,2-a]pyridines

Advances in the last decade for the synthesis of the imidazo[1,2-<i>a</i>]pyridine scaffold from various substrates employing approaches such as multicomponent reactions, tandem processes, rearrangement reactions, inter- and intramolecular oxidative/reductive cyclizations, and transition-metal-catalyzed C–H activation are summarized in this review. The mechanisms for the selected transformations are also discussed. 1 Introduction 2 From 2-Aminopyridines 2.1 Revisiting Traditional Cyclocondensation 2.1.1 Regioselectivity in Cyclocondensation 2.2 Reactions of Carbonyl Compounds 2.3 Reactions of α,β-Unsaturated Carbonyl Compounds 2.4 Reactions of Nitroolefins 2.5 Reactions of Alkynes 2.6 Multicomponent Reactions 2.6.1 Three-Component Reaction of Aldehyde, 2-Aminopyridine, and Isocyanide 2.6.2 Three-Component Reaction of 2-Aminopyridine, Aldehyde, and Alkyne 2.6.3 Other Multicomponent Procedures 2.7 Reactions of N-Substituted 2-Aminopyridines 2.8 Miscellaneous Reactions 3 From Pyridines 3.1 Multicomponent Reactions 4 From Pyridinium Salts 5 From Imidazoles 5.1 Reactions of Heterocyclic Ketene Aminals 6 Miscellaneous Methods 7 Conclusion

Copper-catalyzed [3 + 2] cycloaddition/oxidation reactions between nitro-olefins and organic azides: highly regioselective synthesis of NO2-substituted 1,2,3-triazoles.

A new copper-catalyzed [3 + 2] cycloaddition/oxidation reaction of nitro-olefins with organic azides has been developed to afford 1,4(-NO2),5-trisubstituted 1,2,3-triazoles. This reaction sequence has a broad substrate scope and affords NO2-substituted 1,2,3-triazoles with high regioselectivities and in good to excellent yields. The involved oxidative process overcomes the elimination of HNO2 for general cycloaddition of nitro-olefins with organic azides, which shows a high atom economy and potential applications.

Unusual reactivity of nitronates with an aryl alkyl carbonate: synthesis of α-amino esters.

The monoanions of nitroalkanes are ambident nucleophiles that react with carbonate electrophiles through the oxygen atom. Products arising from reactivity at the carbon atom will yield α-nitro esters, which are precursors for α-amino esters. We demonstrate this in the reactions of nitroalkanes with benzyl phenyl carbonate and DABCO where α-nitro esters are obtained instead of nitrile oxides. The products are readily reduced to α-amino esters. This pathway could be a safe alternative to the Strecker reaction.

N-heterocyclic carbene organocatalytic reductive β,β-coupling reactions of nitroalkenes via radical intermediates.

An unprecedented N-heterocyclic carbene catalytic reductive β,β-carbon coupling of α,β-nitroalkenes, by using an organic substrate to mimic the one-electron oxidation role of the pyruvate ferredoxin oxidoreductase (PFOR) in living systems, has been developed. The reaction goes through a radical anion intermediate generated under a catalytic redox process. For the first time, the presence of radical anion intermediate in NHC organocatalysis is observed and clearly verified.