Nickel-catalyzed oxidative decarboxylative coupling reactions between alkynyl carboxylic acids and arylboronic acids

An Efficient and Sustainable Approach to Decarboxylative Cross-Coupling Using Silica Coated Magnetic Copper Nanocatalyst for the Synthesis of Internal Alkynes

A highly efficient magnetically separable copper nanocatalyst has been developed for decarboxylative cross-coupling reaction for the alkynylation of haloarenes using alkynoic acid as a reaction partner. The chemical nature, morphology, size, and magnetic properties of the prepared nanocatalyst were studied by SEM, TEM, EDS, FT-IR, VSM, and ICP techniques. Remarkably, this catalyst represents the first successful copper based heterogeneous system for this type of coupling that provides a low-cost, stable, and environmentally friendly magnetically recoverable entity that can be re-used for seven consecutive runs without appreciable loss in its catalytic performance.

Pd-Catalyzed decarboxylative alkynylation of alkynyl carboxylic acids with arylsulfonyl hydrazides via a desulfinative process

The decarboxylative alkynylation of alkynyl carboxylic acids and arylsulfonyl hydrazides by desulfinative coupling could provide aryl alkynes in satisfactory yields by either judiciously selecting palladium catalysts or modulating phosphine ligands under mild conditions.

Palladium-Catalyzed Decarboxylative Coupling of Alkynyl Carboxylic Acids with Aryl Tosylates

Decarboxylative coupling reactions of alkynyl carboxylic acids with aryl tosylates were developed in the presence of a palladium catalyst. Among the commercially available phosphine ligands, only 1-dicyclohexylphosphino-2-(di-tert-butylphosphino-ethyl)ferrocene (CyPF-tBu) showed good reactivity. The reaction took place smoothly and gave the decarboxylative coupled products in moderate to good yields. This demonstrates the excellent functional group tolerance toward alkyl, alkoxy, fluoro, thiophenyl, ester, and ketone groups. In addition, alkyl-substituted propiolic acids, such as octynoic and hexynoic acids, were coupled with phenyl tosylate to provide the desired products. We found that the electronic properties of the substituents on the phenyl ring in arylpropiolic acids are an important factor. The order of reactivity was found to be aryl iodide > aryl bromide > aryl tosylate > aryl chloride. However, aryl chloride-bearing electron-withdrawing groups showed higher reactivity than those bearing aryl tosylates.