scholarly journals Palladium catalyzed oxidative aminations and oxylations: where are we?

2016 ◽  
Vol 88 (4) ◽  
pp. 381-389 ◽  
Author(s):  
Mélanie M. Lorion ◽  
Julie Oble ◽  
Giovanni Poli
Keyword(s):  
Carboxylic Acid ◽  
Carboxylic Acids ◽  
Product Formation ◽  
Sigmatropic Rearrangement ◽  
Reaction Pathways ◽  
Reaction Conditions ◽  
Initial Substrate ◽  
Palladium Catalyzed ◽  
Oxidative Acetoxylation

AbstractSelective product formation in the Pd-catalyzed cyclization of unsaturated amide and carboxylic acid derivatives is an intriguing and challenging task. We recently discovered that the oxidative intramolecular Pd(II)-catalyzed amination or oxylation of unsaturated N-sulfonyl carbamates, N-sulfonyl carboxamides and carboxylic acids takes place through the involvement of cyclic (usually, 5- or 6-membered) aminopalladated (AmPIs) or oxypalladated (OxPI) intermediates. Such cyclic intermediates can undergo a variety of transformations such as distocyclic β-H elimination, oxidative acetoxylation or intramolecular carbopalladation, depending upon the substrate and/or the reaction conditions. In the absence of appropriate reaction pathways, the cyclic nucleopalladated intermediates (NuPIs) simply engage in an inconsequential equilibrium with the initial substrate and other transformations occur such as allylic C–H activation or, in the particular case of allyl carbamates, [3,3]-sigmatropic rearrangement.

scholarly journals Stereoselective Palladium-Catalyzed C(sp3)–H Mono-Arylation of Piperidines and Tetrahydropyrans with a C(4) Directing Group

2021 ◽  
Author(s):  
Amalia-Sofia Piticari ◽  
Daniele Antermite ◽  
Joe I. Higham ◽  
J. Harry Moore ◽  
Matthew P. Webster ◽  
...  
Keyword(s):  
Carboxylic Acid ◽  
Carboxylic Acids ◽  
Functional Groups ◽  
One Pot ◽  
Palladium Catalyzed ◽  
Directing Group

A selective Pd-catalyzed C(3)–H cis-functionalization of piperidine and tetrahydropyran carboxylic acids is achieved using a C(4) aminoquinoline amide auxiliary. High mono- and cis-selectivity is attained by using mesityl carboxylic acid as an additive. Conditions are developed with significantly lower reaction temperatures (≤50 °C) than other reported heterocycle C(sp3)–H functionalization reactions, which is facilitated by a DoE optimization. A one-pot C–H functionalization-epimerization procedure provides the trans-3,4-disubstituted isomers directly. Divergent aminoquinoline removal is accomplished with the installation of carboxylic acid, alcohol, amide and nitrile functional groups. Overall fragment compounds suitable for screening are generated in 3–4 steps from readily-available heterocyclic carboxylic acids.

scholarly journals Direct β- and γ-C(sp3)–H Alkynylation of Free Carboxylic Acids

2020 ◽  
Author(s):  
Francesca Ghiringhelli ◽  
Manuel van Gemmeren
Keyword(s):  
Carboxylic Acid ◽  
Carboxylic Acids ◽  
Synthetic Methods ◽  
Broad Scope ◽  
Palladium Catalyzed ◽  
Directing Group

In this study we report the identification of a novel class of ligands for palladium-catalyzed C(sp3)–H activation that enables the direct alkynylation of free carboxylic acid substrates. In contrast to previous synthetic methods no introduction/removal of an exogenous directing group is required. A broad scope of acids including both α-quaternary and challenging α-non-quaternary can be used as substrates. Additionally, the alkynylation in the distal γ-position is reported. Finally, this study encompasses preliminary findings on an enantioselective variant of the title transformation as well as synthetic applications of the products obtained.

scholarly journals Direct β- and γ-C(sp3)–H Alkynylation of Free Carboxylic Acids

2020 ◽  
Author(s):  
Francesca Ghiringhelli ◽  
Manuel van Gemmeren
Keyword(s):  
Carboxylic Acid ◽  
Carboxylic Acids ◽  
Synthetic Methods ◽  
Broad Scope ◽  
Palladium Catalyzed ◽  
Directing Group

In this study we report the identification of a novel class of ligands for palladium-catalyzed C(sp3)–H activation that enables the direct alkynylation of free carboxylic acid substrates. In contrast to previous synthetic methods no introduction/removal of an exogenous directing group is required. A broad scope of acids including both α-quaternary and challenging α-non-quaternary can be used as substrates. Additionally, the alkynylation in the distal γ-position is reported. Finally, this study encompasses preliminary findings on an enantioselective variant of the title transformation as well as synthetic applications of the products obtained.

Synthesis of pregnane 3-carboxylic acids via Pd-catalyzed alkoxycarbonylation and their effect on NMDA receptor activity

2011 ◽  
Vol 76 (9) ◽  
pp. 1141-1161 ◽  
Author(s):  
Eva Šťastná ◽  
Hana Chodounská ◽  
Vladimír Pouzar ◽  
Jiřina Borovská ◽  
Ladislav Vyklický
Keyword(s):  
Nmda Receptor ◽  
Carboxylic Acid ◽  
Voltage Clamp ◽  
Carboxylic Acids ◽  
Substitution Reaction ◽  
Hippocampal Neurons ◽  
Receptor Activity ◽  
Induced Responses ◽  
Palladium Catalyzed ◽  
Leaving Groups

We have prepared 20-oxo-5α- and 20-oxo-5β-pregnane-3-carboxylic acids by palladium catalyzed alkoxycarbonylation using triflate and nonaflate as the leaving groups in this substitution reaction. The activity of the synthesized compounds was studied in cultured rat hippocampal neurons under voltage-clamp conditions. The 5β-carboxylic acid derivatives were found to diminish NMDA-induced responses, whereas the 5α-derivative potentiated the response.

scholarly journals Biotransformation of Carboxylic Acids to Alcohols: Characterization of Thermoanaerobacter Strain AK152 and 1-Propanol Production via Propionate Reduction

2020 ◽  
Vol 8 (6) ◽  
pp. 945
Author(s):  
Sean Michael Scully ◽  
Johann Orlygsson
Keyword(s):  
Carboxylic Acids ◽  
Ethanol Yield ◽  
Kinetic Studies ◽  
Short Chain Fatty Acids ◽  
Product Formation ◽  
Ph Optimum ◽  
Initial Substrate ◽  
Maximum Conversion ◽  
Theoretical Ethanol Yield ◽  
Physiological Tests

Thermoanaerobacter strains have recently gained interest because of their ability to convert short chain fatty acids to alcohols using actively growing cells. Thermoanaerobacter thermohydrosulfuricus strain AK152 was physiologically investigated for its ethanol and other alcohol formation. The temperature and pH optimum of the strain was 70 °C and pH 7.0 and the strain degraded a variety of compounds present in lignocellulosic biomass like monosaccharides, disaccharides, and starch. The strain is highly ethanologenic, producing up to 86% of the theoretical ethanol yield form hexoses. Strain AK152 was inhibited by relatively low initial substrate (30 mM) concentration, leading to inefficient degradation of glucose and levelling up of all end-product formation. The present study shows that the strain produces alcohols from most of the tested carboxylic acids, with the highest yields for propionate conversion to propanol (40.7%) with kinetic studies demonstrating that the maximum conversion happens within the first 48 h of fermentation. Various physiological tests were performed to maximize the acid conversion to the alcohol which reveals that the optimum pH for propionate conversion is pH 6.7 which affords a 57.3% conversion. Kinetic studies reveal that propionate conversion is rapid, achieving a maximum conversion within the first 48 h of fermentation. Finally, by using 13C NMR, it was shown that the addition of propionate indeed converted to propanol.

One Pot Conversion of Carboxylic Acid to Ketone Using Trimethylsilyl Chloride

2020 ◽  
Vol 07 ◽  
Author(s):  
Habtamu Gelaw Mekonnen ◽  
Samaresh Jana
Keyword(s):  
Organic Chemistry ◽  
Natural Products ◽  
Carboxylic Acid ◽  
Carboxylic Acids ◽  
Organometallic Reagent ◽  
Trimethylsilyl Ester ◽  
Reaction Conditions ◽  
One Pot ◽  
Simple Process ◽  
Organolithium Reagents

Background: Ketone is abundant in many natural products and in pharmaceuticals. It is believed to be one of the important functional groups in organic chemistry. Till date,several research approaches have been made to access ketone from a readily available starting materials. One such notable transformation consists of the conversion of carboxylic acid to the corresponding ketone in a one pot manner. Objective: We aimed to develop a simple one pot reaction for the conversion of carboxylic acid to ketone. This reaction could be useful to convert all types of carboxylic acid to ketone in a facile manner. Methods: In this procedure, a carboxylic acid has been converted to the corresponding trimethylsilyl ester using trimethylsilyl chloride in the presence of a base. A suitable organometallic reagent can interact with the ester formed at 20°C to produce the corresponding ketone. Results: Under the optimized reaction conditions, various aromatic, aliphatic and heteroaromatic carboxylic acids have been converted to the corresponding ketones using organolithium reagents, in a one pot manner. Moderate to good yields of the desired ketones were observed in most of the transformations. Conclusion: Conversion of carboxylic acid to ketone has been reported in a one pot fashion, where carboxylic acid has been transformed to its silyl ester. Organolithium reagents were used as nucleophile for our reaction purpose, whereas the organomagnesium reagents were not useful for this transformation. Aliphatic, aromatic and heteroaromatic carboxylic acids have been converted to the ketones following a simple process.

Exploration of Mesyl Chloride in a One Pot Conversion of Carboxylic Acids to Ketones

2020 ◽  
Vol 7 (3) ◽  
pp. 242-247
Author(s):  
Habtamu Gelaw Mekonnen ◽  
Debasis Sahoo ◽  
Samaresh Jana ◽  
Sanjoy Kumar Maji
Keyword(s):  
Carboxylic Acid ◽  
Carboxylic Acids ◽  
Functional Group ◽  
Reaction Times ◽  
Mixed Anhydride ◽  
Organometallic Reagent ◽  
Reaction Conditions ◽  
One Pot ◽  
Organometallic Reagents ◽  
Organolithium Reagents

Background: Due to the ubiquitous nature of the ketone functionality, it is considered an important functional group in organic chemistry. Hence, the synthesis of ketones from readily available starting materials is an important chemical transformation in organic synthesis. Consequently, several research efforts have been reported in the literature for the transformation of carboxylic acids to ketones in a one-pot synthesis. However, some of the procedures have limitations, such as long reaction times, harsh reaction conditions, and usage of expensive metal catalysts. Thus, a simple and convenient one-pot conversion of carboxylic acids to ketones remains desirable. Objective: We intended to develop a simple and convenient one-pot methodology for the synthesis of ketones from carboxylic acids. Our objective was to build up a carboxylic acid-based chemical template where various types of organometallic reagents can interact to produce the desired ketone. Methods: In this procedure, a carboxylic acid was converted to a mixed anhydride using mesyl chloride in the presence of a base. This mixed anhydride was then reacted with a suitable organometallic reagent at -20°C to obtain the desired ketone. The reaction was performed in a one-pot fashion. Results: Under the optimized reaction conditions, various aromatic and heteroaromatic carboxylic acids were converted to the corresponding ketones using organolithium and organomagnesium reagents with short reaction times. Moderate to good yields of the desired ketones were observed in many of these transformations. Conclusion: A simple and convenient one-pot method for the conversion of carboxylic acids to ketones has been reported. Specifically, various aromatic and `heteroaromatic carboxylic acids have been converted to the corresponding ketones in moderate to good yields. Organomagnesium and organolithium reagents were used as nucleophiles for this reaction.

The Direct Pd-Catalyzed β-C(sp3)–H Activation of Carboxylic Acids

Synlett ◽  
2018 ◽  
Vol 29 (15) ◽  
pp. 1937-1943 ◽  
Author(s):  
Manuel van Gemmeren ◽  
Alexander Uttry
Keyword(s):  
Carboxylic Acid ◽  
Carboxylic Acids ◽  
Bond Activation ◽  
State Of The Art ◽  
Acid Moiety ◽  
Straightforward Manner ◽  
Aliphatic Acids ◽  
Tremendous Progress ◽  
Palladium Catalyzed ◽  
Directing Group

The carboxylic acid moiety is one of the most versatile and abundant functional groups. However, despite of tremendous progress in the field of C–H functionalization reactions its use as a directing group for C(sp3)–H activation has remained limited. In this Synpact article we present the challenges associated with the carboxylic acid moiety as a native directing group and report on the newest developments in this field, including our recent study in which we developed a generally applicable protocol for the direct palladium catalyzed β-C(sp3)–H arylation of propionic acid and related α-branched aliphatic acids giving access to hydrocinnamic acids derivatives in a highly straightforward manner.1 Introduction2 Challenges in the C(sp3)–H Bond Activation of Carboxylic Acids3 History/State of the Art4 Studies towards a General β-C(sp3)–H Functionalization of ­Aliphatic Acids5 Conclusion

Synthetic plant growth regulators. VI. The partial synthesis of optically active (4β,15α)-18-Norkaurene-15-carboxylic acids from (4β)-18-norkauren-3-one by means of a pyrrolidinium ylide rearrangement

1980 ◽  
Vol 33 (9) ◽  
pp. 2061 ◽  
Author(s):  
AL Cossey ◽  
LN Mander ◽  
JV Turner
Keyword(s):  
Carboxylic Acid ◽  
Plant Growth ◽  
Carboxylic Acids ◽  
Plant Growth Regulators ◽  
Growth Regulators ◽  
Sodium Borohydride ◽  
Sigmatropic Rearrangement ◽  
Optically Active ◽  
Allylic Amines ◽  
Partial Synthesis

(4β)-18-Norkaur-16-en-3-one (4a) was alternatively acetalized (ethanediol/Dowex resin) or deoxygenated (tosylhydrazine/sodium borohydride); allylic bromination (N-bromosuccinimide) of the products, followed by alkylation of pyrrolidine gave primary allylic amines which were quaternized with chloroacetonitrile. Potassium t-butoxide-induced [2,3]-sigmatropic rearrangement, followed by acidic hydrolysis and Jones oxidation, gave respectively (4β,15α)-3-oxo-18-norkaur-16-ene-15- carboxylic acid (10a) and (4β,15α)-18-norkaur-16-ene-15-carboxylic acid. Reductions of (4a) and (10a) gave, with K-Selectride, axial (3β)- alcohols and, with sodium borohydride, mainly equatorial (3α)-alcohols. Details of a related conversion of (+)-phyllocladene into (15α)- phyllocladene-15-carboxylic acid are also recorded.

scholarly journals Hemiacetal Ester Exchanges, Study of Reaction Conditions and Mechanistic Pathway

Reactions ◽  
2020 ◽  
Vol 1 (2) ◽  
pp. 89-101
Author(s):  
David Boucher ◽  
Jeppe Madsen ◽  
Nicolas Caussé ◽  
Nadine Pébère ◽  
Vincent Ladmiral ◽  
...  
Keyword(s):  
Exchange Rate ◽  
Carboxylic Acid ◽  
Exchange Reaction ◽  
Carboxylic Acids ◽  
Vinyl Ether ◽  
Dihydrogen Phosphate ◽  
Reaction Conditions ◽  
Kinetics Studies ◽  
Mechanistic Pathway ◽  
Reaction Proceeds

A range of hemiacetal esters were synthesized by the reaction between carboxylic acids and butyl vinyl ether using n-dodecyl dihydrogen phosphate as catalyst. Specifically, nonanoic, propionic, acrylic, sebacic, and fumaric acids were used as substrates to prepare the corresponding hemiacetalesters. These compounds were used as model molecules to demonstrate the ability of hemiacetal ester functional groups to undergo the exchange reaction in the presence of weak carboxylic acids without any catalyst. Kinetics studies examined the eect of the carboxylic acid concentration on the exchange rate, and revealed that the exchange reaction proceeds through an associative mechanism.

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