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.

Chloroacetate Promotes and Participates in the Oxidative Annulation of Pyridines/Isoquinoline by Using Oxygen as the Oxidant

The aerobic oxidative annulation of chalcones, pyridines/isoquinoline and ethyl chloroacetate to indolizines was achieved by cascade reaction. Various functional groups on chalcones were tolerated. And different pyridines derivatives could also be suitable substrates. Ethyl chloroacetate is an essential component in participating of the oxidative annulation process. Overall, this protocol is very practical and efficient by using molecular oxygen as oxidant with high selectivity for the annulation product.

Visible light mediated efficient oxidative benzylic sp(3) C-H to ketone derivatives obtained under mild conditions using O2

A photooxygenation of benzylic sp(3) C-H reaction has been demonstrated using O2 mediated by visible light. This protocol provides a simple and mild route to obtain ketones from benzylic sp(3) C-H bonds. Various benzylic sp(3) C-H bonds can be transformed into the desired ketone derivatives in moderate to good yields. The (18)O2 labelling experiments demonstrated that the oxygen introduced into ketone originated from dioxygen. A plausible mechanism has been proposed accordingly.

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.

Spontaneous Oxygenation of Siloxy-N-silylketenimines to α-Ketoamides

Siloxy-N-silylketenimines generated in situ from O-silyl cyanohydrins were converted to α-ketoamides by brief exposure to air or oxygen. Oxidation under extremely mild conditions can be explained by assuming the intermediacy of a 3-imino-1,2-dioxetane derivative generated via triplet-singlet intersystem crossing after the reaction of siloxy-N-silylketenimines with triplet oxygen.

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.

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.

Metal-free oxidative esterification of acetophenones with alcohols: a facile one-pot approach to α-ketoesters

A novel oxidative esterification method for the synthesis of α-ketoesters has been developed, which is a facile one-pot approach to α-ketoesters from acetophenones with alcohols, especially under metal-free conditions with broad substrate scope.

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.

Room temperature copper-catalyzed oxidative amidation of terminal alkynes for the synthesis of α-ketoamides using O-benzoyl hydroxylamines as aminating reagent and oxidant

A novel and convenient copper-catalyzed oxidative amidation for the synthesis of α-ketoamides has been successfully developed, which uses easily available O-benzoyl hydroxylamines as aminating reagent and oxidant.

Synthesis of 2-trifluoromethylquinolines via copper-mediated intramolecular oxidative cyclization of N-(2-alkenylaryl) enamines

A general and efficient copper-mediated intramolecular oxidative cyclization of N-(2-alkenylaryl) enamines for the synthesis of 2-trifluoromethylquinolines has been developed.

Recent Trends in Copper-Catalyzed C-H Amination Routes to Biologically Important Nitrogen Scaffolds

Nitrogen-containing heterocycles have found remarkable applications in natural product research, material sciences, and pharmaceuticals. Although the synthesis of this interesting class of compounds attracted the interest of generations of organic chemists, simple and straightforward assembly methods based on transition-metal catalysis have regularly been elusive. The recent advancements in the development of C-H functionalization have helped in accomplishing the synthesis of a variety of complex heterocycles from simple precursors. This Focus Review summarizes the recent advances in one particular field: the copper-catalyzed C-N bond formation reactions via C-H bond functionalization to furnish a comprehensive range of nitrogen heterocycles. Applicability and synthetic feasibility of a particular reaction represent major requirements for the inclusion in this review.

Predicting hydration propensities of biologically relevant α-ketoamides

Quantum chemical calculations coupled to experiments were used to predict covalent hydration propensities of biologically relevant α-ketoamides. Experimentally determined hydration equilibrium constants for related ketones and aldehydes were compared to computationally determined values to develop a method for predicting hydration equilibrium constants. This method was used on six newly synthesized α-ketoamides to experimentally verify computational predictions. A correlation between calculation and experiment was observed and applied to models of several pertinent APIs. Our results indicate that the keto form is favored for practically all α-ketoamides in biological environs.

Copper-catalyzed efficient direct amidation of 2-methylquinolines with amines

A novel Cu-catalyzed direct amidation of 2-methylquinolines with amines is described. This method afforded an efficient approach for the synthesis of biologically important aromatic amides from readily available coupling partners using molecular oxygen as the oxidant.

Cu-catalyzed aerobic oxidative esterification of acetophenones with alcohols to α-ketoesters

Copper-catalyzed aerobic oxidative esterification of acetophenones with alcohols using molecular oxygen has been developed to form a broad range of α-ketoesters in good yields. In addition to reporting scope and limitations of our new method, mechanism studies are reported that reveal that the carbonyl oxygen in the ester mainly originated from dioxygen.

TEMP and copper cocatalyzed oxygenation of ketones with molecular oxygen: chemoselective synthesis of α-ketoesters

A practical approach to α-ketoesters through TEMP and copper cocatalyzed chemoselective oxidative coupling of methyl ketones with alcohols is developed.

Metal free one-pot synthesis of α-ketoamides from terminal alkenes

A practical approach towards the synthesis of α-ketoamides from terminal alkenes has been developed using I₂/IBX under one-pot reaction conditions.

Cross dehydrogenative coupling (CDC) of aldehydes with N-hydroxyimides by visible light photoredox catalysis

A visible light mediated cross-dehydrogenative-coupling (CDC) reaction has been developed for the synthesis of N-hydroxyester derivatives from aldehydes and N-hydroxyimides.

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.

Cu-catalyzed aerobic oxidative amidation of aryl alkyl ketones with azoles to afford tertiary amides via selective C–C bond cleavage

Chemoselective cleavage of the C(CO)–C(alkyl) bond in aryl ketones leading to azole amides is disclosed. Aryl ketones with a variety of long-chain alkyl groups have been demonstrated to be active substrates and mechanism studies suggested that molecular oxygen serves both as an oxidant and a reactant in this strategy.

Chloroacetate-promoted selective oxidation of heterobenzylic methylenes under copper catalysis

The efficient selective oxidation and functionalization of C-H bonds with molecular oxygen and a copper catalyst to prepare the corresponding ketones was achieved with ethyl chloroacetate as a promoter. In this transformation, various substituted N-heterocyclic compounds were well tolerated. Preliminary mechanistic investigations indicated that organic radical species were involved in the overall process. The N-heterocyclic compounds and ethyl chloroacetate work synergistically to activate C-H bonds in the methylene group, which results in the easy generation of free radical intermediates, thus leading to the corresponding ketones in good yields.