Coupling Reaction Of Carboxylic Acids Research Articles

Mn‐Catalyzed Three‐Component Coupling Reactions of Carboxylic Acids, Diazo Compounds, and Tertiary Amines for the Synthesis of β‐Amino Esters

ABSTRACTA simple and efficient three‐component coupling reaction of carboxylic acids, diazo compounds, and tertiary amines catalyzed by manganese has been described. This reaction proceeds smoothly under mild conditions to afford various β‐amino esters in moderate to good yields by using O2 as the terminal oxidant. In this process, Mn‐based carbene radical, single‐electron transfer, and nucleophilic attack were fused into a reaction system.

Advancements in double decarboxylative coupling reactions of carboxylic acids.

The double decarboxylative coupling reaction between two (similar or different) molecules of carboxylic acids is an emerging area that has gained considerable attention as a new avenue for forging carbon-carbon bonds. Since this synthetic strategy only utilizes carboxylic acids as easily accessible, non-toxic and stable starting materials, and extrudes carbon dioxide (CO2) as the only waste by-product, it can be considered as an environmentally benign alternative to traditional coupling reactions which mainly rely on the use of toxic organic halides or organometallic reagents. The aim of this review is to highlight the recent advances and developments in this exciting new field that may serve as inspiration for future research to mature it.

Reaction of aromatic carboxylic acids with phenylacetylene with the participation of a zinc catalyst

The reaction of benzoic, 4-methylbenzoic, 2-bromobenzoic and 4-bromobenzoic acids with phenylacetylene was carried out in a toluene solution at a temperature of 110 0C in the presence of a catalyst - 1 mol % [Zn(C4H7S2)4](NO3)2. In the coupling reaction of carboxylic acids with phenylacetylene a mixture of coupling products is formed according to the Markovnikov and anti-Markovnikov rules. A reaction mechanism was proposed and it was found that the yield of vinyl esters increased in the serie 4-CH3-C6H4COOH< C6H5COOH< 4-Br-C6H4COOH< 2-Br-C6H4COOH. It was found that with an increasing acidity of the carboxylic acids, the product formed by Markovnikov rule has been formed in a larger amount. On the contrary, as the acidity of the starting compounds decreased, the amount of the anti-Markovnikov coupling product has increased. The total yield of reaction products of phenylacetylene with carboxylic acid is 44% (65/35) in 4-methylbenzoic acid, 67% (80/20) in benzoic acid, 78% (82/18) in 4-bromobenzoic acid, 82% (85 /15) in 2-bromobenzoic acid. The structure of the synthesized vinyl esters was proved on the base of the analysis of IR, 1H, 13C NMR and Mass spectrums.

Nickel‐Catalyzed Reductive Coupling of Carboxylic Acids with Disulfides to Access Thioesters

AbstractA nickel‐catalyzed reductive cross coupling reaction of carboxylic acids with disulfides is described. The readily available and inexpensive carboxylic acid is activated in situ by the formation of a mixed anhydride. The transformation occurs at room temperature with wide functional group tolerance to efficiently generate structurally diverse thioesters. Moreover, the reaction tolerated a broad substrate scope, including sterically hindered of disulfides. Ultimately, this powerful method could be applied to the late‐stage functionalization for the construction of diverse thioesters, affording a convenient and practical tactic to construct carbon‐sulfur bonds.

Palladium-Catalyzed Synthesis of Aryl Ketones from Carboxylic Acids and Arylboronic Acids Using 2-Chloroimidazolium Chloride as a Coupling Reagent

AbstractCarboxylic acids are an abundant and structurally diverse class of commercially available materials, which are commonly used as stable reagents in organic synthesis. The Suzuki–Miyaura coupling reaction directly using carboxylic acid as a substrate has been rarely reported. Here, we report an efficient coupling reaction of carboxylic acids with arylboronic acids in toluene in the presence of IPrCl-Cl, Pd(OAc)2, PPh3, and K3PO4·7H2O at 90 °C to give the corresponding aryl ketones.

Dehydrative/Decarboxylative Coupling of Carboxylic Acids with Allylic Alcohols

Herein reported is a dehydrative/decarboxylative coupling reaction of carboxylic acids with allylic alcohols, which is co-catalyzed by photoredox and palladium catalysts. α-Hetero- or aryl-substitu...

Organophotocatalyzed E and Z stereoselective [formula omitted] bond forming cross coupling reactions of carboxylic acids with β-aryl-vinyl halides

Owing to their importance in organic synthesis, transition metal catalyzed cross-coupling reactions have been the focus of many studies. Recently, it was recognized that merged transition metal and photoredox catalysis is a powerful strategy for the design of challenging Csp3-Csp2 bond forming cross coupling reactions. However, these reactions require metals (e.g., Ni) to activate Csp2-halogen bonds. In the current investigation, we developed a new, photocatalysis based, metal free approach to accomplish Csp3-Csp2 bond formation between an alkyl fragment, derived from a carboxylic acid, and a vinyl moiety of a,β-aryl-substituted vinyl halide. The cross coupling process, which is activated by using the simple organic dye 4CzIPN, acting as a single electron transfer type photocatalyst, and visible light, is chemoselective, E-stereoselective and efficient. Moreover, upon prolonged irradiation of the reaction mixture, 4CzIPN serving as an energy transfer photocatalyst, promotes isomerization of the initially formed alkenes into mixtures enriched in the Z-isomers.

Branching Out: Rhodium-Catalyzed Allylation with Alkynes and Allenes.

We present a new and efficient strategy for the atom-economic transformation of both alkynes and allenes to allylic functionalized structures via a Rh-catalyzed isomerization/addition reaction which has been developed in our working group. Our methodology thus grants access to an important structural class valued in modern organic chemistry for both its versatility for further functionalization and the potential for asymmetric synthesis with the construction of a new stereogenic center. This new methodology, inspired by mechanistic investigations by Werner in the late 1980s and based on preliminary work by Yamamoto and Trost, offers an attractive alternative to other established methods for allylic functionalization such as allylic substitution or allylic oxidation. The main advantage of our methodology consists of the inherent atom economy in comparison to allylic oxidation or substitution, which both produce stoichiometric amounts of waste and, in case of the substitution reaction, require prefunctionalization of the starting material. Starting out with the discovery of a highly branched-selective coupling reaction of carboxylic acids with terminal alkynes using a Rh(I)/DPEphos complex as the catalyst system, over the past 5 years we were able to continuously expand upon this chemistry, introducing various (pro)nucleophiles for the selective C-O, C-S, C-N, and C-C functionalization of both alkynes and the double-bond isomeric allenes by choosing the appropriate rhodium/bidentate phosphine catalyst. Thus, valuable compounds such as branched allylic ethers, sulfones, amines, or γ,δ-unsaturated ketones were successfully synthesized in high yields and with a broad substrate scope. Beyond the branched selectivity inherent to rhodium, many of the presented methodologies display additional degrees of selectivity in regard to regio-, diastereo-, and enantioselective transformations, with one example even proceeding via a dynamic kinetic resolution. Many advances presented in this account were driven by detailed mechanistic investigations including DFT-calculations, ESI-MS and in situ IR experiments and enabled the application of our chemistry for target-oriented syntheses demonstrated by several examples shown herein. In general, this research topic has matured over the past years into a viable option when synthesizing chiral compounds, from small molecules such as quercus lactones to complex target structures such as Homolargazole or Clavosolide A. This demonstrates the importance and utility of these coupling reactions, especially considering the ease with which carbon-heteroatom bonds can be built stereoselectively, with many of the product classes displaying motifs common in modern APIs.

A novel aromatic carbocation-based coupling reagent for esterification and amidation reactions.

A novel tropylium-based coupling reagent has been developed to facilitate the synthesis of a series of esters, amides, lactones and peptides under mild reaction conditions. Remarkably, this reagent can be used in catalytic amounts in conjunction with a sacrificial reagent, offering a new and efficient method for nucleophilic coupling reactions of carboxylic acids.

Epimerization‐Free C‐Terminal Peptide Activation

Smooth operation: C-terminal peptide activation with full stereointegrity was accomplished using a copper(II)-mediated coupling reaction of carboxylic acids with arylboroxines (see scheme, NCL = native chemical ligation, Boc = tert-butoxycarbonyl). This method allows epimerization-free activation and ligation of peptides with racemization-prone phenylglycine at the C terminus.

ChemInform Abstract: Thio‐Mediated Two‐Component Coupling Reaction of Carboxylic Acids and Isonitriles under Mild Conditions.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Thio-mediated two-component coupling reaction of carboxylic acids and isonitriles under mild conditions

The coupling reaction between carboxylic acids and isonitriles in the presence of thiophenol as activator under mild conditions is described.

ChemInform Abstract: Two New Catalysts for the Dehydrogenative Coupling Reaction of Carboxylic Acids with Silanes—Convenient Methods for an Atom‐Economical Preparation of Silyl Esters.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Two New Catalysts for the Dehydrogenative Coupling Reaction of Carboxylic Acids with Silanes—Convenient Methods for an Atom‐Economical Preparation of Silyl Esters

Tris(triphenylphosphine)cuprous chloride [Cu(PPh3)3Cl] has been found to be an efficient catalyst for the dehydrosilylation of carboxylic acids with silanes. In the presence of 4 mol% Cu(PPh3)3Cl, dehydrosilylation reactions in acetonitrile afforded the corresponding silyl esters at 80°C in good yields. It was noted that triphenylphosphine itself also functions as an adequate catalyst for the reaction.

Triphenylphosphine‐Catalyzed Dehydrogenative Coupling Reaction of Carboxylic Acids with Silanes — A Convenient Method for the Preparation of Silyl Esters.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.

Triphenylphosphine‐Catalyzed Dehydrogenative Coupling Reaction of Carboxylic Acids with Silanes – A Convenient Method for the Preparation of Silyl Esters

AbstractTriphenylphosphine has been found to be an efficient catalyst for the dehydrosilylation of carboxylic acids with silanes. In the presence of 4 mol % of triphenylphosphine (PPh3), dehydrosilylation reactions in DMF afforded the corresponding silyl esters at 120 °C in good yield.

Synthesis of Optically Pure Bisphosphine Oxides and Related Compounds

Abstract Optically pure bisphosphine oxides were conveniently synthesized by Kolbe electrolytic coupling reaction of carboxylic acids possessing a chiral phosphinoyl group in 60—65% isolated yield. This synthetic approach provides a variety of accesses to P-chiral bisphosphine ligands. Their absolute configurations were intercorrelated with that of the previous reported BisP*-borane. Asymmetric hydrogenation of α-(acylamino)acrylic acids by a rhodium complex with BisP* (R = t-octyl or 1,1,3,3-tetramethylbutyl) affords N-acylamino acids in 94—96% ee.

Spectrophotometric Determination of Carboxylic acids with 2-Mitrophenylhydrazine in Aqueous Solution

Abstract Carboxylic acids were determined spectrophotometrically by converting them into 2-nitrophenylhydrazides. The coupling reaction of carboxylic acids with 2-nitrophenylhydrazine was effected by a water-soluble carbociimide, 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide, and proceeded efficiently in aqueous solution buffered at pH 4.5 with pyridine and hydrochloric acid. The yields of hydrazides from acetic and benzoic acids were nearly quantitative. The reaction mixture was then made strongly alkaline, and after heating to reduce the blank absorbance, the absorbance of the hydrazide was measured at around 540 nm. Calibration curves of various carboxylic acids were linear between 0.02 and 0.5 μmol through the origin.