Aminocarbonylation of Aryl Tosylates to Carboxamides

Pd/C-Catalyzed Oxidative Aminocarbonylation of Aryldiazonium Tetrafluoroborate Salts through sp3CN Bond Activation of Inert Tertiary Amines to Tertiary Amides

Aryldiazonium tetrafluoroborate salts are highly accessible from readily available and inexpensive amines, and by realizing these advantages, an efficient protocol is developed that employs aryldiazonium tetrafluoroborate salts as an effective electrophile for oxidative aminocarbonylation with unreactive tertiary amines. In this, molecular oxygen has been used as an ideal and green oxidant, which activates the inert CN bond. Various derivatives of aryldiazonium tetrafluoroborate salts are prepared, which include different electron-withdrawing and electron-donating group substituents. This protocol utilizes Pd/C as a heterogeneous catalyst, which is smoothly recyclable. Moreover, this developed method is ligand and cocatalyst free, and it does not require any base to activate the amines as nucleophile, and the new process effectively provides a mild pathway toward a variety of tertiary amide moieties with significant yield. This way, the potent protocol is economical, simple, recyclable, and operates at milder conditions and contributes toward valuable products that are vital in an industrial domain.

Continuous-Flow Ritter Reaction for Sustainable Amide Synthesis Using a Recyclable m-Phenolsulfonic Acid-Formaldehyde Resin Catalyst

Herein, a rapid and efficient continuous-flow synthesis of amides is described. The Ritter reaction, catalyzed by a reusable solid acid catalyst composed of m-phenolsulfonic acid-formaldehyde resin (PAFR II), was used to convert nitriles and alcohols to amides in up to 90% yield. The continuous-flow system facilitates short reaction times and maintains activity for several weeks. This method is scalable, environmentally sustainable, and enables catalyst recycling.

Regioselective C-H Active Carbonylation via 1,4-Palladium Migration

We report a highly regioselective three-component coupling reaction of styrene, CO gas, and an amine compound to synthesize multisubstituted α,β-unsaturated amides, which involves a palladium-catalyzed sequential 1,4-palladium migration, C(sp²)-H activation, carbonylation, and amination. Salient features of this strategy include the use of 1 atm of CO, excellent stereochemistry, and good functional group tolerance. Further, a series of control experiments and density functional theory calculations were performed to afford some insights for the transfer mechanism.

Tunable Pd/C-catalyzed Oxidative Alkoxycarbonylation /Aminocarbonylation of Aryl hydrazines with Alcohols / Inert Tertiary amines through C−N Bond Activation

We report Pd/C-catalyzed oxidative aminocarbonylation and alkoxycarbonylation of unactiavated aryl hydrazines. This protocol employs inert tertiary amines as an aminal source and arylhydrazines via oxidative sp3 and sp2 C−N bond...

Pd-Catalyzed Oxidative Aminocarbonylation of Arylboronic Acids with Unreactive Tertiary Amines via C-N Bond Activation

An efficient synthesis of tertiary amides from aryl boronic acids and inert tertiary amines through the oxidative carbonylation via C(sp³)-N bond activation is presented. This protocol significantly restricts the homocoupling biarylketone product. It involves the use of a homogeneous PdCl₂/CuI catalyst and a heterogeneous Pd/C based catalyst, which promotes C(sp³)-N bond activation of tertiary amines with aryl boronic acids. This process represents a ligand-free, base-free, and recyclable catalyst along with an ideal oxidant like molecular oxygen.

Dichotomy of Atom-Economical Hydrogen-Free Reductive Amidation vs Exhaustive Reductive Amination

Rh-catalyzed one-step reductive amidation of aldehydes has been developed. The protocol does not require an external hydrogen source and employs carbon monoxide as a deoxygenative agent. The direction of the reaction can be altered simply by changing the solvent: reaction in THF leads to amides, whereas methanol favors formation of tertiary amines.

Mo(CO)6 as a Solid CO Source in the Synthesis of Aryl/Heteroaryl Weinreb Amides under Microwave-Enhanced Condition

The facile transformation of aryl/heteroaryl nonaflates into corresponding amides via Pd-catalyzed aminocarbonylation using Mo(CO)6 as a solid CO source under microwave-enhanced condition is reported. The method was found to be tolerant with respect to a diverse range of electronically biased aryl/heteroaryl nonaflates, and exceptional yields were obtained. The optimized protocol was further extended to a diverse range of amines.

Palladium-Catalyzed Highly Chemoselective Intramolecular C-H Aminocarbonylation of Phenethylamines to Six-Membered Benzolactams

A palladium-catalyzed highly selective intramolecular C-H aminocarbonylation of Br-functionalized phenethylamines in the presence of CO was achieved while leaving the C-Br bond unreacted to afford six-membered benzolactams with good to high yields. The remaining C-Br group in the cyclized product was successfully used as a reactive center for further functionalization through various palladium-catalyzed coupling reactions.

Palladium-catalyzed carbonylative transformation of aryl chlorides and aryl tosylates

The developments in the carbonylative transformations of aryl chlorides and aryl tosylates have been collected and discussed.