Search

Alkynyl carboxylic acids undergo decarboxylative coupling with amines and paraformaldehyde, using a continuous flow reaction system to give propargylamines in excellent yields.

Palladium-catalyzed aminocarbonylation for the synthesis of alkynyl amides from the coupling reactions of alkynyl carboxylic acids, amines, and carbon monoxide is reported.

A trifluoroethylation of alkynes through a palladium-catalyzed decarboxylative coupling reaction was developed. When alkynyl carboxylic acids and ICH2CF3 were allowed to react with [Pd(η3-allyl)Cl]2/XantPhos and Cs2CO3 in N,N-dimethylformamide (DMF) at 80 °C for 1 h, the desired products were formed in good yields. This catalytic system showed high functional group tolerance.

The three-component reaction of aryl halides, sodium sulfide pentahydrate (Na2S⋅5 H2O), and propiolic acid in the presence of 2.5% bis(triphenylphosphine)palladium chloride [Pd(PPh3)2Cl2], 5% 1,4-bis(diphenylphosphino)butane (dppb) and 2 equivalents of 1,8-diazabicycloundec-7-ene (DBU) produces stereoselectively (Z)-3-arylthioacrylic acids in good yields. A study of the reaction pathway suggested that the CS bond formation between aryl halides and Na2S⋅5 H2O proceeded first, and the resulting intermediate reacted with propiolic acid to produce the desired product. In addition, when the resulting product was treated with acid, the respective thiochromenones were formed in good yields.

A variety of 2-iodoanilines and aromatic/heteroaromatic aldehydes undergo the title reaction.

Only trace amounts of symmetrical diarylalkynes are obtained in some cases as by- products.

The reaction proceeds in the presence of a phase transfer surfactant and is efficiently catalyzed by two different systems.

Symmetrical diarylalkynes were obtained from propiolic acid (or 2-butynedioic acid) and aryl halides in good yields. The optimized reaction conditions were 2.0 equiv of aryl halide, 1.0 equiv of propiolic acid, 5.0 mol % Pd(PPh3)2Cl2, 10.0 mol % 1,4-bis(diphenylphosphino)butane (dppb), 2.0 equiv of 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU), and dimethyl sulfoxide (DMSO) as the solvent. The coupling reaction of 2-butynedioic acid with aryl halides required 110 °C. The coupling reaction showed tolerance for functional groups such as ester, ketone, and aldehyde and exhibited chemoselectivity. In the coupling reaction of propiolic acid with aryl bromide, the diarylated product was the major one at 80 °C, even though 1 equiv of aryl halides was employed. However, among the monoarylated products that were formed predominantly at 25 and 50 °C in the coupling reaction with aryl iodide, more Sonogashira coupling product was obtained than the decarboxylative coupling product. Unsymmetrical diarylalkynes were also sy...

Nickel-catalyzed aminocarbonylation of aryl halides is described. A well-defined air-stable nickel-phosphite catalytic system (Ni(OAc)(2).4H(2)O/phosphite 1) effectively promoted the aminocarbonylation of aryl bromides with a range of formamides to give the corresponding aryl amide products in moderate to good yields. The less hindered formamide required lower catalytic loading for full conversion and produced higher yields than the more hindered one. It also exhibited base-dependent activity toward formamides.