Radical decarboxylative phosphorylation of carboxylic acids

Thiohydroxomic corboxylic mixed anhydrides (e.g. 1) react at room temperature with (PhS)₃P to give, through a decarboxylative phosphorylation reaction, the corresponding dithiophosphonates 12 in moderate yields.     

Silver-catalyzed decarboxylative halogenation of carboxylic acids

Decarboxylative halogenation of carboxylic acids catalyzed by silver carbonate is reported. ortho-Nitrobenzoic acids react with copper(II) chloride or bromide in DMF/DMSO at 130-140 °C leading to the corresponding aryl halides in moderate to good yields.     

Silver-catalyzed decarboxylative chlorination of aliphatic carboxylic acids

Decarboxylative halogenation of carboxylic acids, the Hunsdiecker reaction, is one of the fundamental functional group transformations in organic chemistry. As the initial method requires the preparations of strictly anhydrous silver carboxylates, several modifications have been developed to simplify the procedures. However, these methods suffer from the use of highly toxic reagents, harsh reaction conditions, or limited scope of application. In addition, none is catalytic for aliphatic carboxylic acids. In this Article, we report the first catalytic Hunsdiecker reaction of aliphatic carboxylic acids. Thus, with the catalysis of Ag(Phen)(2)OTf, the reactions of carboxylic acids with t-butyl hypochlorite afforded the corresponding chlorodecarboxylation products in high yields under mild conditions. This method is not only efficient and general, but also chemoselective. Moreover, it exhibits remarkable functional group compatibility, making it of more practical value in organic synthesis. The mechanism of single electron transfer followed by chlorine atom transfer is proposed for the catalytic chlorodecarboxylation.     

Palladium-catalyzed highly regioselective and stereoselective decarboxylative arylation of unactivated olefins with aryl carboxylic acids

Palladium(II)-catalyzed highly regioselective and stereoselective decarboxylative arylation of unactivated olefins with aryl carboxylic acids has been developed. This method is applicable to a variety of unactivated olefins, including allylamides, long chain functionalized olefins and purely aliphatic olefins, leads to the formation of linear E-configured products in high yields. Both electron-rich and electron-deficient aryl carboxylic acids are suitable arylation reagents. It was found that the choice of solvent, catalyst precursor and oxidant had an important influence on reaction efficiency. As a co-solvent and ligand, DMSO is critical to catalysis. This chemistry expands the scope of decarboxylative arylation of olefins with aryl carboxylic acids, and provides a rapid access to useful linear arylation products of unactivated olefins.     

New decarboxylative chalcogenation of aliphatic and alicyclic carboxylic acids.

Thiohydroxamic-carboxylic mixed anhydrides can be decarboxylated in the presence of diaryl disulphides, diselenides and ditellurides to give sulphides, selenides and tellurides respectively in reasonable to good yield.     

Copper-catalyzed decarboxylative cross-coupling of alkynyl carboxylic acids with aryl halides

The copper-catalyzed decarboxylative reactions of alkynyl carboxylic acids with aryl halides were performed under relatively mild reaction conditions. Benzofurans could be further prepared smoothly by a one-pot domino protocol on the basis of decarboxylative cross-coupling of 2-iodophenol.     

Silver-catalyzed decarboxylative alkynylation of aliphatic carboxylic acids in aqueous solution

C(sp(3))-C(sp) bond formations are of immense interest in chemistry and material sciences. We report herein a convenient, radical-mediated and catalytic method for C(sp(3))-C(sp) cross-coupling. Thus, with AgNO(3) as the catalyst and K(2)S(2)O(8) as the oxidant, various aliphatic carboxylic acids underwent decarboxylative alkynylation with commercially available ethynylbenziodoxolones in aqueous solution under mild conditions. This site-specific alkynylation is not only general and efficient but also functional group compatible. In addition, it exhibits remarkable chemo- and stereoselectivity.     

Silver-catalyzed decarboxylative fluorination of aliphatic carboxylic acids in aqueous solution

Although fluorinated compounds have found widespread applications in the chemical and materials industries, general and site-specific C(sp(3))-F bond formations are still a challenging task. We report here that with the catalysis of AgNO(3), various aliphatic carboxylic acids undergo efficient decarboxylative fluorination with SELECTFLUOR(?) reagent in aqueous solution, leading to the synthesis of the corresponding alkyl fluorides in satisfactory yields under mild conditions. This radical fluorination method is not only efficient and general but also chemoselective and functional-group-compatible, thus making it highly practical in the synthesis of fluorinated molecules. A mechanism involvinig Ag(III)-mediated single electron transfer followed by fluorine atom transfer is proposed for this catalytic fluorodecarboxylation.     

Photocatalytic decarboxylative amidosulfonation enables direct transformation of carboxylic acids to sulfonamides

Sulfonamides feature prominently in organic synthesis, materials science and medicinal chemistry, where they play important roles as bioisosteric replacements of carboxylic acids and other carbonyls. Yet, a general synthetic platform for the direct conversion of carboxylic acids to a range of functionalized sulfonamides has remained elusive. Herein, we present a visible light-induced, dual catalytic platform that for the first time allows for a one-step access to sulfonamides and sulfonyl azides directly from carboxylic acids. The broad scope of the direct decarboxylative amidosulfonation (DDAS) platform is enabled by the efficient direct conversion of carboxylic acids to sulfinic acids that is catalyzed by acridine photocatalysts and interfaced with copper-catalyzed sulfur–nitrogen bond-forming cross-couplings with both electrophilic and nucleophilic reagents.

Sulfonamides are now accessible directly from carboxylic acids by a one-step, tricomponent decarboxylative amidosulfonation that provides the missing link between the two key functionalities.     

Insight into copper-catalyzed decarboxylative thiolation of carboxylic acids in the gas phase

Organocopper complexes bearing bidentate nitrogen ligands were synthesized in the gas phase by electrospray ionization mass spectrometry. Gas-phase decarboylative thiolation reaction was carried out in the ion-trap analyzer by collision-induced dissociation and ion-molecule reaction. The carboxylic acids were finally converted to thioethers as a neutral loss via collision-induced dissociation. During this process, copper acetate acted as a catalyst, and the valence state change of copper was observed. Meanwhile, the mechanism of decarboxylative thiolation was examined. This reaction was also suitable for different carboxylic acids and bidentate nitrogen ligands in the gas phase.     

Highly effective copper-catalyzed decarboxylative coupling of aryl halides with alkynyl carboxylic acids

We have developed a highly effective copper-catalyzed decarboxylative coupling of alkynylcarboxylic acids with various aryl and alkyl halides at 2 mol% loading of copper. This method is simple, economical and practical for the synthesis of disubstituted alkyne compounds.     

Pd-catalysed decarboxylative Suzuki reactions and orthogonal Cu-based O-arylation of aromatic carboxylic acids

Pd-catalysed decarboxylative Suzuki reactions and orthogonal Cu-based O-arylation reactions of aromatic carboxylic acids are reported. The new reactions may provide alternative routes for the synthesis of some biaryls and aromatic carboxylic esters.     

Copper-catalyzed decarboxylative coupling of aryl halides with alkynyl carboxylic acids performed in water

Most alkynes are volatile liquids, which are relatively difficult to use and to transport. In contrast, alkynyl carboxylic acids offer a stable and attractive alternative for the alkynylation reactions. Here, we employed alkynyl carboxylic acids as reaction partners for the alkynylation of aryl halides. Copper-catalyzed decarboxylative coupling, including various challenging aryl bromides with phenylpropiolic acid, was performed in water without using co-solvents with good yields. Our approach provides a low-loading, low-cost, stable and environmentally friendly copper catalyst system for decarboxylative coupling.     

Pd-catalyzed carbonylative reactions of aryl iodides and alkynyl carboxylic acids via decarboxylative couplings

Alkynyl carboxylic acids reacted with aryl iodides under a CO atmosphere in the presence of a palladium catalyst to produce α,β-alkynyl aryl ketones in good yields. The maximum turnover number was 16?800. The desired carbonylative coupling was formed from phenyl propiolic acid without any formation of a noncarbonylative coupling product in the absence of CuI. However, the reaction with alkyl-substituted alkynyl carboxylic acids required CuI as a cocatalyst for high yield.     

Selective deuteration of (hetero)aromatic compounds via deutero-decarboxylation of carboxylic acids

A practical, mild and highly selective protocol for the monodeuteration of a variety of arenes and heteroarenes is presented. Catalytic amounts of Ag(I) salts in DMSO/D(2)O are shown to facilitate the deutero-decarboxylation of ortho-substituted benzoic and heteroaromatic α-carboxylic acids in high yields with excellent levels of deuterium incorporation.     

Palladium-catalyzed intramolecular decarboxylative coupling of arene carboxylic acids/esters with aryl bromides

Give me a ring? An efficient approach has been developed for the intramolecular decarboxylative coupling of arene carboxylic acids/esters with aryl bromides catalyzed by palladium (see scheme). From a synthetic viewpoint, this method is highly attractive because the catalyst loading is low, the optimized reaction conditions are mild, and the substrate scope is broad.     

Palladium-catalyzed decarboxylation and decarbonylation under hydrothermal conditions: decarboxylative deuteration

[reaction: see text] Decarboxylation of free carboxylic acid was performed by Pd/C catalyst under hydrothermal water (250 degrees C/4 MPa). Under the hydrothermal conditions of deuterium oxide, decarbonylative deuteration was observed to give fully deuterated hydrocarbons from carboxylic acids or aldehydes.