Direct Synthesis of α-Ketoamides via Copper-Catalyzed Reductive Amidation of Nitroarenes with α-Oxocarboxylic Acids

Nitroarenes are known for their stability, low toxicity, easy availability, and cost-effectiveness, making them one of the most fundamental chemical feedstocks. The direct utilization of nitroarenes as nitrogen sources in amidation reactions offers significant advantages over using arylamines. Herein, we disclose a streamlined method for constructing α-ketoamides through the direct coupling of nitroarenes with α-oxocarboxylic acids. This transformation obviates the need for preparing, isolating, and purifying arylamines, leading to improved efficiency, cost-effectiveness, and time savings.

Atmospheric Oxygen Facilitated Oxidative Amidation to α-Ketoamides and Unusual One Carbon Degradative Amidation to N-Alkyl Amides

A mild, transition-metal-free novel synthetic approach for the construction of C═O and C-N bonds has been demonstrated. Easily accessible gem-dibromoalkenes under similar conditions form oxidative amidation product α-ketoamides and unusual degradative amidation product N-alkyl amides by simply changing the amine substitute. Atmospheric air containing molecular oxygen proved to be an ideal oxidant for an amidation reaction. Under similar conditions, the electron-deficient gem-dibromoalkenes play a dual role with different formamides forming novel oxidative amidation products and by the state of art neighboring group participation of amine to unusual one-carbon degradative amidation products.

Metal-Free Syntheses of α-Ketothioamide and α-Ketoamide Derivatives from Sulfoxonium Ylides

An efficient base, additive and metal-free synthetic methods for α-ketothioamide and α-ketoamide derivatives from readily available sulfoxonium ylides have been described. Sulfoxonium ylides with primary or secondary amines afforded α-ketothioamides in the presence of elemental sulfur, whereas α-ketoamides were produced when I2 and TBHP were present. The reaction proceeded well at room temperature and generated the corresponding molecules in good to excellent yields. The reaction can be scaled-up and tolerated by a range of functional groups with simple operational procedures.

One-Pot Synthesis of α-Ketoamides from α-Keto Acids and Amines Using Ynamides as Coupling Reagents

A one-pot strategy for α-keto amide bond formation have been developed by using ynamides as coupling reagents under extremely mild reaction conditions. Diversely structural α-ketoamides were afforded in up to 98% yield for 36 examples. This reaction features advantages such as practical coupling procedure, wide functional group tolerance, and extremely mild conditions and has potential applications in synthetic and medicinal chemistry.

Diversification of α-ketoamides via transamidation reactions with alkyl and benzyl amines at room temperature

A wide range of N-tosyl α-ketoamides underwent transamidation with various alkyl amines in the absence of a catalyst, base, or additive. On the other hand, transamidation in N-Boc α-ketoamides was achieved in the presence of Cs₂CO₃. The reactions proceeded at room temperature and provided good to excellent yields of transamidation products under the optimized conditions. Broad substrate scope, functional group tolerance and quick conversions are the important features of the developed methodology.

I2-DMSO mediated oxidative amidation of methyl ketones with anthranils for the synthesis of α-ketoamides

An I₂-DMSO mediated oxidative amidation of methyl ketones using anthranils as masked N-nucleophiles has been developed for the direct synthesis of α-ketoamides with high atom-economy. This metal-free process involves reductive N-O bond cleavage of anthranils and oxidative C-N bond formation of methyl ketones under mild conditions. The iodo group and electrophilic formyl group provide multiple possibilities for further functionalization of α-ketoamides.

Silver/manganese dioxide nanorod catalyzed hydrogen-borrowing reactions and tert-butyl ester synthesis

Silver/manganese dioxide (Ag@MnO2) nanorods are synthesized and characterized by scanning electron microscopy, transmission electron microscopy, energy dispersive X-ray spectroscopy, X-ray powder diffraction, and X-ray photoelectron spectroscopy. It was discovered that Ag@MnO2 nanorods can realize hydrogen-borrowing reactions in high yields and are also effective for the synthesis of tert-butyl esters from aryl cyanides and tert-butyl hydroperoxide in a short period of time. Mechanistic experiments revealed that this catalytic system acts as a Lewis acid in hydrogen-borrowing reactions, while the synthesis of tert-butyl esters occurs through a radical pathway. This is the first report on the excellent catalytic activity of Ag@MnO2 nanorods as a catalyst.

CuO-decorated magnetite-reduced graphene oxide: a robust and promising heterogeneous catalyst for the oxidative amidation of methylarenes in water via benzylic sp3 C–H activation

CuO-decorated magnetite-reduced graphene oxide: a heterogeneous catalyst for the oxidative amidation of methylarenes in water at room temperature.

Copper-Catalyzed Oxidative Synthesis of α-Ketoamides from Aryl Methyl Ketones and N-Bromobutanimide Using N,N-Dimethylformamide as Dimethylamine Source

A novel and practical Cu(OAc)2-catalyzed oxidative synthesis of α-ketoamides from aryl methyl ketones and N-bromobutanimide (NBS) using N,N-dimethylformamide (DMF) as dimethylamine (HNMe2) source and solvent has been developed under mild conditions. DMF was used as a HNMe2 source and can be easily converted into HNMe2 by acid hydrolysis. The mechanistic studies indicate that Cu(OAc)2 plays a dual role in providing both catalyst and oxidant.

Direct synthesis of 2-oxo-acetamidines from methyl ketones, aromatic amines and DMF via copper-catalyzed C(sp3)-H amidination

A convenient method for the synthesis of 2-oxo-acetamidines from methyl ketones using aromatic amines and DMF as nitrogen sources is reported via copper-catalyzed C(sp3)-H amidination. Various methyl ketones react readily with aromatic amines and DMF, producing 2-oxo-acetamidines in yields of 47 to 92%. This protocol features the simultaneous formation of C-N and C[double bond, length as m-dash]N bonds using DMF and aromatic amines as two different nitrogen sources. It thus provides an efficient approach to construct acyclic amidines via three C(sp3)-H bond amidination. Based on the preliminary experiments, a plausible mechanism of this transformation is disclosed.

Cu-Catalyzed carbamoylation versus amination of quinoline N-oxide with formamides

Carbamoylation and amination of quinoline with formamides was developed via copper-catalyzed C–C and C–N bond formations.

Selective synthesis of aryl thioamides and aryl-α-ketoamides from α-oxocarboxylic acids and tetraalkylthiuram disulfides: an unexpected chemoselectivity from aryl sulfonyl chlorides

Tosyl chloride-controlled generation of thioamides and α-ketoamides via base-promoted decarboxylative reaction of α-oxocarboxylic acids with tetraalkylthiuram disulfides has been established.

Recent Uses of N,N-Dimethylformamide and N,N-Dimethylacetamide as Reagents

N,N-Dimethylformamide and N,N-dimethylacetamide are multipurpose reagents which deliver their own H, C, N and O atoms for the synthesis of a variety of compounds under a number of different experimental conditions. The review mainly highlights the corresponding literature published over the last years.

Recent developments in functionalization of acyclic α-keto amides

This review describes the synthetic utility of α-keto amides to synthesize various important molecules via mono, dual and triple functionalization reactions.

Solvent-free one-pot oxidation of ethylarenes for the preparation of α-ketoamides under mild conditions

Here we developed a highly efficient solvent-free, one-pot procedure for synthesizing α-ketoamides from ethylarenes and amines, by oxidizing a C–H bond sp³ center.

One pot synthesis of α-ketoamides from ethylarenes and amines: a metal free difunctionalization strategy

One-pot and metal free synthesis of α-ketoamides has been described through in situ generation of aryl ketones from easily available ethylarenes followed by amidation with various amines. This multiple oxidation protocol involves catalytic I₂-pyridine-TBHP (t-butyl hydroperoxide) mediated oxidative benzylic carbonylation and sequential NaI-TBHP mediated oxidative amidation without using any solvent.

An efficient method for the preparation of tert-butyl esters from benzyl cyanide and tert-butyl hydroperoxide under the metal free condition

A novel protocol to synthesize tert-butyl esters from benzyl cyanides and tert-butyl hydroperoxide has been successfully achieved. Csp³–H bond oxidation, C–CN bond cleavage and C–O bond formation proceeded smoothly in one pot under the metal-free condition.

Copper–TEMPO-catalyzed synthesis of α-ketoamides via tandem sp3C–H aerobic oxidation and amination of phenethyl alcohol derivatives

The first synthesis of α-ketoamides from phenethyl alcohol derivatives, simple and readily available substrates, was achieved.

A two-step continuous synthesis of α-ketoamides and α-amino ketones from 2° benzylic alcohols using hydrogen peroxide as an economic and benign oxidant

A practical two-step flow synthesis of α-ketoamides and α-amino ketones via direct oxidative coupling between 2° benzylic alcohols and amines was developed.

Transition metal-free synthesis of α-ketoamides from arylmethyl ketones and alkylphosphoramides

Synthesis of α-ketoamides from arylmethyl ketones and hexalkylphosphoramides using TBAI as the catalyst and TBHP as the oxidant.

I2-promoted aerobic oxidative coupling of acetophenes with amines under metal-free conditions: facile access to α-ketoamides

A novel and efficient I₂-promoted oxidative coupling of acetophenes with amines to α-ketoamides is presented, which employs molecular oxygen as an environmentally friendly oxidant under metal-free conditions.

Formamidine hydrochloride as an amino surrogate: I2-catalyzed oxidative amidation of aryl methyl ketones leading to free (N–H) α-ketoamides

A highly efficient molecular iodine catalyzed oxidative amidation of aryl methyl ketones has been developed. This reaction represents a novel strategy for the synthesis of free (N–H) α-ketoamides.

Highly regioselective para-methylthiolation/bridging methylenation of arylamines promoted by NH4I

Aryl methyl thioethers and methylene-bridged arylamines were synthesized via highly regioselective para-methylthiolation/bridging methylenation of arylamines using DMSO as the methylthio or methylene source in the presence of NH₄I under metal-free conditions.

Peroxide promoted tunable decarboxylative alkylation of cinnamic acids to form alkenes or ketones under metal-free conditions

In the presence of DTBP or DTBP/TBHP, the decarboxylative alkylation of cinnamic acids with alkanes gave alkenes and ketones respectively via a radical mechanism in moderate to good yields.

Syntheses of thiol and selenol esters by oxidative coupling reaction of aldehydes with RYYR (Y = S, Se) under metal-free conditions

Thiol (selenol) esters were synthesized by a direct oxidative coupling reaction of aldehydes with disulfides (diselenides) under metal-free conditions.