Palladium-Catalyzed Oxidative N-Dealkylation/Carbonylation of Tertiary Amines with Alkynes to α,β-Alkynylamides

Metal-free photoinduced generation and alkynylation of carbamoyl radicals: a facile synthesis of alkynyl amides

A metal-free photoinduced alkynylation of carbamoyl radicals with hypervalent iodine(III) reagents for a facile synthesis of alkynyl amides is described. This protocol features good functional group tolerance and a broad substrate scope for direct synthesis of alkynyl amide derivatives in good to excellent yields under mild and redox-neutral reaction conditions. The synthetic application is demonstrated by the late-stage installation of alkynyl amides into natural products and active pharmaceutical relevant molecules. The mechanistic studies indicated the simultaneous existence of photoredox catalytic and direct photoexcited processes, and the quantum yields confirmed the occurrence of the radical chain propagation process.

The synthesis of alk-2-ynl Weinreb amides via Pd/Cu-catalysed oxidative carbonylation of terminal alkynes

Synthesis of alk-2-ynl-Weinreb amides via Pd-catalyzed oxidative carbonylation of terminal alkynes and N,O-dimethylhydroxylamine hydrochloride at room temperature under low CO/O2 pressure is reported for the first time. This protocol offers tolerance of various functional groups under mild reaction conditions. The protocol incorporates aromatic- and aliphatic-substituted alkynes through a one-step oxidative carbonylative route toward desired alkynyl Weinreb amides, which are of considerable importance as valuable synthetic building blocks.

Pd-catalysed synthesis of oxomalonamides through adjacent triple carbonylation of tertiary amines

The monocarbonylation and dicarbonylation reactions are well-established reactions in carbonylation chemistry. This work reports unusual oxidative adjacent triple carbonylation of the tertiary amine towards oxomalonamide synthesis using a Pd catalyst. The protocol involves the use of inert tertiary amines as an active reservoir of secondary amines through sp3 C-N bond activation using O2 as an ideal oxidant.

Thiuram Disulfide Mediated Cu-Catalyzed Amidation of Terminal Alkynes: An Efficient Synthesis of Alkynyl Amides

Terminal alkynes undergo a CO-free aminocarbonylation reaction mediated by thiuram disulfides. Thiuram disulfide acts as the source of the carbamoyl group in the amidation of terminal alkynes in the presence of copper-based reagent and catalyst. A series of alkynyl amides has been prepared with several structural variations following the current one-pot two-step protocol. The reaction proceeds through a mixed disulfide intermediate, which has been isolated and characterized by single-crystal XRD analysis.

Nickel-Catalyzed Amidation of Aryl Alkynyl Acids with Tetraalkylthiuram Disulfides: A Facile Synthesis of Aryl Alkynyl Amides

Nickel-catalyzed amidation of aryl alkynyl acids using tetraalkylthiuram disulfides as the amine source is described, affording a series of aryl alkynyl amides in good to excellent yields under mild conditions. This general methodology provides an alternative pathway for the synthesis of useful aryl alkynyl amides in an operationally simple manner, which shows its practical synthetic value in organic synthesis. The mechanism of this transformation was explored through control experiments and DFT calculations.

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...

Synthesis of alkynamides through reaction of alkyl- or aryl-substituted alkynylaluminums with isocyanates

An efficient and facile method for the preparation of alkynamides through Et₃N-catalyzed alumination of alkyl- or aryl-substituted terminal alkynes with AlMe₃ and sequential nucleophilic addition of in situ generated alkynylaluminums to isocyanates is described. This method has the merits of using readily available isocyanates and monosubstituted alkynes, easy access to organoaluminums, short reaction times, and high efficiency. A gram-scale synthesis of the desired alkynamide and its application to the formation of α-methylene-β-lactams demonstrates the synthetic utility of this method.

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.

Metal-Free Synthesis of 2- N, N-Dialkylaminobenzoxazoles Using Tertiary Amines as the Nitrogen Source

The unprecedented reaction of tertiary amines with 2(3 H)-benzoxazolones has been investigated. In the presence of the Ph₃P-I₂ reagent system, the reaction of both acyclic and cyclic aliphatic tertiary amines led to the formation of 2- N, N-dialkylaminobenzoxazoles with the selective cleavage of an alkyl group. Especially, N-(2-iodoethyl)piperazinyl derivatives were rapidly produced in good yields when using DABCO as the nitrogen source. Only in the cases when the nucleophilicity of the substrates exceeds that of the amine, competitive self-condensation of benzoxazolones then proceeds preferentially. ³¹P{¹H}-NMR study suggested the involvement of an aryloxyphosphonium intermediate and/or possibly 2-iodobenzoxazole which activates the C-2 position of benzoxazolones toward nucleophilic aromatic substitution.

Pd/C-catalyzed synthesis of oxamates by oxidative cross double carbonylation of alcohols and tertiary amines through C–N bond cleavage

Palladium-catalyzed oxidative cross double carbonylation reaction between tertiary amines and alcohols using oxidant O₂ and KI as the additive affords oxamates. Oxamate are as a intermediate in biological active compound and glycol synthesis.

Palladium-Catalyzed Three-Component Reaction: A Novel Method for the Synthesis of N-Acyl Propiolamides

Palladium-catalyzed three-component reactions between terminal alkynes, isonitriles, and sodium carboxylates have been developed. This novel and operationally simple methodology provides an alternative for the synthesis of N-acyl propiolamide derivatives under mild conditions using isonitriles as the amine source and sodium carboxylates as the oxygen and acyl source.

Selectivity Controlled Palladium-Catalyzed Carbonylative Synthesis of Propiolates and Chromenones from Phenols and Alkynes

An interesting selectivity-controlled palladium-catalyzed oxidative carbonylation procedure for the synthesis of propiolates and chromenones has been developed. Starting from phenols and alkynes, under slightly different conditions, various propiolates and chromenones can be isolated in moderate to good yields. Additionally, this also presents the first example of direct carbonylative annulation of nonpreactivated phenols and terminal alkynes to produce chromenones.

NH4I/tert-Butyl Hydroperoxide-Promoted Oxidative C–N Cleavage of Tertiary Amines Leading to Nitroaromatic Compounds

A NH4I/ tert-butyl hydroperoxide-promoted oxidation of tertiary N-aryl- N,N-dialkylamines in DMSO has been developed to access nitroaromatic compounds. This methodology involves sequential N-dealkylation reactions in one-pot and a radical pathway is proposed.

Palladium(II)-Catalysed Aminocarbonylation of Terminal Alkynes for the Synthesis of 2-Ynamides: Addressing the Challenges of Solvents and Gas Mixtures

2-Ynamides can be synthesised through Pd^II catalysed oxidative carbonylation, utilising low catalyst loadings. A variety of alkynes and amines can be used to afford 2-ynamides in high yields, whilst overcoming the drawbacks associated with previous oxidative methods, which rely on dangerous solvents and gas mixtures. The use of [NBu₄ ]I allows the utilisation of the industrially recommended solvent ethyl acetate. O₂ can be used as the terminal oxidant, and the catalyst can operate under safer conditions with low O₂ concentrations.

Metal-free radical oxidative alkoxycarbonylation and imidation of alkanes

The metal-free radical oxidative carbonylation of alkanes proceeded to give the corresponding esters and imides in good to high yields.

Palladium-Catalyzed Ylidyl-Carbonylation of Aryl Halides To Produce α-Acylphosphoranes

An efficient synthesis of α-acylphosphoranes by palladium-catalyzed carbonylation of aryl iodides with carbon monoxide and stabilized phosphonium ylides has been developed. Featuring 44 examples, the protocol displayed a wide substrate scope under mild reaction conditions, showcasing its potential in synthetic organic chemistry.