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.

Silver-Catalyzed Decarboxylative Acylation of Isocyanides Accesses to α-Ketoamides with Air as a Sole Oxidant

α-Ketoamide moieties, as privileged units, may represent a valuable option to develop compounds with favorable biological activities, such as low toxicity, promising PK and drug-like properties. An efficient silver-catalyzed decarboxylative acylation of α-oxocarboxylic acids with isocyanides was developed to derivatize the α-ketoamide functional group via a multicomponent reaction (MCR) cascade sequence in one pot. A series of α-ketoamides was synthesized with three components of isocyanides, aromatic α-oxocarboxylic acid analogues and water in moderate yields. Based on the research, the silver-catalyzed decarboxylative acylation confirmed that an oxygen atom of the amide moiety was derived from the water and air as a sole oxidant for the whole process.

Palladium-catalyzed tandem Heck/carbonylation/aminocarbonylation en route to chiral heterocyclic α-ketoamides

An unprecedented tandem carbonylation/aminocarbonylation triggered by palladium-catalyzed enantioselective Heck-type exocyclopalladation delivering chiral heterocyclic α-ketoamides has been developed.

Mg(OtBu)2-catalyzed C–H oxidation of α-azido arylethanones using TBHP as the oxidant and carbonyl oxygen source: facile access to primary α-ketoamides

A Mg(OtBu)2-catalyzed C(sp3)–H oxidation of α-azido arylethanones to straightforwardly produce primary α-ketoamides is presented.

A copper iodide-catalyzed coupling reaction of benzofuran-3(2H)-ones with amines: an approach to α-ketoamides

A CuI-catalyzed coupling reaction of benzofuran-3(2H)-ones with amines has been well established for the direct synthesis of α-ketoamides. This process involves C-O bond cleavage and C[double bond, length as m-dash]O/C-N bond formation. Mechanism studies indicated that this α-ketoamide formation reaction may involve a free radical process.

Metal-free electrochemical synthesis of α-ketoamides via decarboxylative coupling of α-keto acids with isocyanides and water

A mild and convenient electrochemical protocol has been developed for the preparation of α-ketoamides via a decarboxylative coupling reaction of α-keto acids with isocyanides and water.

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.

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.

Copper-catalyzed coupling of anthranils and α-keto acids: direct synthesis of α-ketoamides

Copper-catalyzed coupling of α-keto acids with anthranils is reported for the synthesis of α-ketoamides bearing an aldehyde group via N–O/C–O bond cleavages and C–N bond formation.

Direct defluorinative amidation-hydrolysis reaction of gem-difluoroalkenes with N,N-dimethylformamide, and primary and secondary amines

A novel and efficient method for the synthesis of arylacetamides by the reactions of gem-difluoroalkenes with N,N-dialkylformamides, and primary and secondary amines with the assistance of KOtBu and water was developed.

Palladium-Catalyzed Serendipitous Synthesis of Arylglyoxylic Amides from Arylglyoxylates and N,N-Dialkylamides in the Presence of Halopyridines

A palladium-catalyzed synthesis of arylglyoxylic amides by the reaction of arylglyoxylates and N,N-dialkylamides in the presence of a 2,3-dihalopyridine has been realized for the first time. An anticipated 2,3-diaroylpyridine did not form in this reaction. The current study unveils an unprecedented role of 2,3-dihalopyridine toward this amidation. Our mechanistic study reveals that the arylglyoxylate could react with halopyridine to form a traceless activated pyridyl ester of arylglyoxylic acid, which upon subsequent reaction with amino surrogate, N,N-dialkylamides could form the arylglyoxylic amides.

Facile Access to Amides from Oxygenated or Unsaturated Organic Compounds by Metal Oxide Nanocatalysts Derived from Single-Source Molecular Precursors

Oxidative amidation is a valuable process for the transformation of oxygenated organic compounds to valuable amides. However, the reaction is severely limited by the use of an expensive catalyst and limited substrate scope. To circumvent these limitations, designing a transition-metal-based nanocatalyst via more straightforward and economical methodology with superior catalytic performances with broad substrate scope is desirable. To resolve the aforementioned issues, we report a facile method for the synthesis of nanocatalysts NiO and CuO by the sol-gel-assisted thermal decomposition of complexes [Ni(hep-H)(H₂O)₄]SO₄ (SSMP-1) and [Cu(μ-hep)(BA)]₂ (SSMP-2) [hep-H = 2-(2-hydroxylethyl)pyridine; BA = benzoic acid] as single-source molecular precursors (SSMPs) for the oxidative amidation of benzyl alcohol, benzaldehyde, and BA by using N,N-dimethylformamide (DMF) as the solvent and as an amine source, in the presence of tert-butylhydroperoxide (TBHP) as the oxidant, at T = 80 °C. In addition to nanocatalysts NiO and CuO, our previously reported Co/CoO nanocatalyst (CoNC), derived from the complex [Co^II(hep-H)(H₂O)₄]SO₄ (A) as an SSMP, was also explored for the aforementioned reaction. Also, we have carefully investigated the difference in the catalytic performance of Co-, Ni-, and Cu-based nanoparticles synthesized from the SSMP for the conversion of various oxygenated and unsaturated organic compounds to their respective amides. Among all, CuO showed an optimum catalytic performance for the oxidative amidation of various oxygenated and unsaturated organic compounds with a broad reaction scope. Finally, CuO can be recovered unaltered and reused for several (six times) recycles without any loss in catalytic activity.

Ag(i)/persulfate-catalyzed decarboxylative coupling of α-oxocarboxylates with organotrifluoroborates in water under room temperature

The decarboxylative coupling of α-oxocarboxylates and organotrifluoroborates was carried out smoothly in water under room temperature. This novel and simple method is efficient, using AgNO₃/K₂S₂O₈ catalytic system to generate diarylketone products.

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.

Cu(i)-Functionalized SBA-16: an efficient catalyst for the synthesis of α-ketoamides under moderate conditions

An efficient catalyst based on the cage-like mesoporous material SBA-16 as the support and Cu(i) as active sites has been successfully prepared. The catalyst demonstrated high catalytic activity (up to 88%) in the direct oxidative synthesis of α-ketoamides between acetophenone and piperidine, employing O2 from open air as the oxidant without other additives. A heterogeneous catalyst was applied in this reaction for the first time, and the catalyst could be easily separated from the reaction system by filtration and reused several times without a significant loss of activity.

A novel coupling reaction of α-halo ketones promoted by SmI3/CuI

In the presence of SmI₃ and catalyzed by CuI in DMF, α-haloketones were transformed unexpectedly into α-hydroxy-1,4-diketones. The mechanism was probed and DMF was assumed to play a dual role both as a hydroxyl source and as a solvent.

Copper-catalyzed, hypervalent iodine mediated CC bond activation of enaminones for the synthesis of α-keto amides

An unprecedented approach toward the general synthesis of α-keto amides has been established by tailoring the CC double bond of enaminones in the presence of CuI and hypervalent iodine.

Recent advances in catalytic decarboxylative acylation reactions via a radical process

This review highlights the recent advances in radical decarboxylative cross-coupling reactions of α-keto acids which provide powerful tools for C–C and C–X bond formations.