scholarly journals New Chemistry with Old Functional Groups: On the Reaction of Isonitriles with Carboxylic Acids—A Route to Various Amide Types

2008 ◽  
Vol 130 (16) ◽  
pp. 5446-5448 ◽  
Author(s):  
Xuechen Li ◽  
Samuel J. Danishefsky
Keyword(s):  
Carboxylic Acids ◽  
Functional Groups

Generation of Phosphoranyl Radicals via Photoredox Catalysis Enables Voltage–Independent Activation of Strong C–O Bonds

2018 ◽  
Author(s):  
Erin Stache ◽  
Alyssa B. Ertel ◽  
Tomislav Rovis ◽  
Abigail G. Doyle
Keyword(s):  
Carboxylic Acids ◽  
Functional Groups ◽  
Single Step ◽  
Direct Access ◽  
Photoredox Catalysis ◽  
Acyl Radical ◽  
Synthetic Strategy ◽  
Acyl Radicals ◽  
Benzyl Radicals ◽  
Aliphatic Carboxylic Acids

Alcohols and carboxylic acids are ubiquitous functional groups found in organic molecules that could serve as radical precursors, but C–O bonds remain difficult to activate. We report a synthetic strategy for direct access to both alkyl and acyl radicals from these ubiquitous functional groups via photoredox catalysis. This method exploits the unique reactivity of phosphoranyl radicals, generated from a polar/SET crossover between a phosphine radical cation and an oxygen centered nucleophile. We first show the desired reactivity in the reduction of benzylic alcohols to the corresponding benzyl radicals with terminal H-atom trapping to afford the deoxygenated product. Using the same method, we demonstrate access to synthetically versatile acyl radicals which enables the reduction of aromatic and aliphatic carboxylic acids to the corresponding aldehydes with exceptional chemoselectivity. This protocol also transforms carboxylic acids to heterocycles and cyclic ketones via intramolecular acyl radical cyclizations to forge new C–O, C–N and C–C bonds in a single step.

scholarly journals Palladium(II)-Catalyzed C(sp3)–H Activation of N,O-Ketals towards a Method for the β-Functionalization of Ketones

Synlett ◽  
2019 ◽  
Vol 30 (04) ◽  
pp. 454-458 ◽  
Author(s):  
Danny Ho ◽  
Jonas Calleja ◽  
Matthew Gaunt
Keyword(s):  
Carboxylic Acids ◽  
Functional Groups ◽  
Building Blocks ◽  
Activation Pathway ◽  
Bond Forming ◽  
Aliphatic Ketones ◽  
Palladium Catalyzed

A method for the formal β-functionalization of aliphatic ketones via a palladium-catalyzed sp3 C–H activation pathway is reported. An N,O-ketal directs an aliphatic C–H carbonylation to form γ-lactams which upon hydrolysis generate γ-keto carboxylic acids. This C–C bond-forming reaction is tolerant of a range of functional groups, enabling the synthesis of a range of synthetically important building blocks. Furthermore, the concepts underlying this transformation have also enabled the development of a related C–H alkenylation process to highly functionalised heterocycles.

scholarly journals Elongated and substituted triazine-based tricarboxylic acid linkers for MOFs

2016 ◽  
Vol 12 ◽  
pp. 2267-2273 ◽  
Author(s):  
Arne Klinkebiel ◽  
Ole Beyer ◽  
Barbara Malawko ◽  
Ulrich Lüning
Keyword(s):  
Nitro Group ◽  
Carboxylic Acids ◽  
Functional Groups ◽  
Acid Chloride ◽  
Methoxy Group ◽  
Suzuki Coupling ◽  
Tricarboxylic Acid

New triazine-based tricarboxylic acid linkers were prepared as elongated relatives of triazinetribenzoic acid (TATB). Additionally, functional groups (NO2, NH2, OMe, OH) were introduced for potential post-synthetic modification (PSM) of MOFs. Functionalized tris(4-bromoaryl)triazine “cores” (3a,3b) were obtained by unsymmetric trimerization mixing one equivalent of an acid chloride (OMe or NO2 substituted) with two equivalents of an unsubstituted nitrile. Triple Suzuki coupling of the cores 3 with suitable phenyl- and biphenylboronic acid derivatives provided elongated tricarboxylic acid linkers as carboxylic acids 17 and 20 or their esters 16 and 19. Reduction of the nitro group and cleavage of the methoxy group gave the respective amino and hydroxy-substituted triazine linkers.

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.

Generation of Phosphoranyl Radicals via Photoredox Catalysis Enables Voltage–Independent Activation of Strong C–O Bonds

2018 ◽  
Author(s):  
Erin Stache ◽  
Alyssa B. Ertel ◽  
Tomislav Rovis ◽  
Abigail G. Doyle
Keyword(s):  
Carboxylic Acids ◽  
Functional Groups ◽  
Single Step ◽  
Direct Access ◽  
Photoredox Catalysis ◽  
Acyl Radical ◽  
Synthetic Strategy ◽  
Acyl Radicals ◽  
Benzyl Radicals ◽  
Aliphatic Carboxylic Acids

Alcohols and carboxylic acids are ubiquitous functional groups found in organic molecules that could serve as radical precursors, but C–O bonds remain difficult to activate. We report a synthetic strategy for direct access to both alkyl and acyl radicals from these ubiquitous functional groups via photoredox catalysis. This method exploits the unique reactivity of phosphoranyl radicals, generated from a polar/SET crossover between a phosphine radical cation and an oxygen centered nucleophile. We first show the desired reactivity in the reduction of benzylic alcohols to the corresponding benzyl radicals with terminal H-atom trapping to afford the deoxygenated product. Using the same method, we demonstrate access to synthetically versatile acyl radicals which enables the reduction of aromatic and aliphatic carboxylic acids to the corresponding aldehydes with exceptional chemoselectivity. This protocol also transforms carboxylic acids to heterocycles and cyclic ketones via intramolecular acyl radical cyclizations to forge new C–O, C–N and C–C bonds in a single step.

Organic-ligand-assisted hydrothermal synthesis of ultrafine and hydrophobic ZnO nanoparticles

2010 ◽  
Vol 25 (2) ◽  
pp. 219-223 ◽  
Author(s):  
Tahereh Mousavand ◽  
Satoshi Ohara ◽  
Takashi Naka ◽  
Mitsuo Umetsu ◽  
Seiichi Takami ◽  
...  
Keyword(s):  
Crystal Growth ◽  
Hydrothermal Synthesis ◽  
Carboxylic Acids ◽  
Functional Groups ◽  
Zno Nanoparticles ◽  
Organic Ligand ◽  
Polymer Matrices ◽  
Organic Modifiers ◽  
Hydrothermal Conditions ◽  
Zno Particles

In this study, we report the synthesis of uniform and narrowly size-distributed ZnO nanoparticles with sizes of approximately 3 nm; the nanoparticles were prepared by means of organic-ligand-assisted hydrothermal conditions with various organic modifiers. The results obtained herein revealed that among the various functional groups tested (alcohols, aldehydes, carboxylic acids, and amines), only hexanol effectively controlled the nucleation and crystal growth of spherical ZnO nanoparticles. The use of hexanol also caused the surface of the ZnO particles to change from hydrophilic to hydrophobic, which would enhance the dispersion of these particles in polymer matrices, paints, cosmetics, and other organic application media.

scholarly journals Assessment of Catalyst Selectivity in Carbon-Nanotube Silylesterification

2019 ◽  
Vol 10 (1) ◽  
pp. 109 ◽  
Author(s):  
Simon Detriche ◽  
Arvind K. Bhakta ◽  
Patrick N’Twali ◽  
Joseph Delhalle ◽  
Zineb Mekhalif
Keyword(s):  
Carboxylic Acids ◽  
Functional Groups ◽  
Zinc Chloride ◽  
Cost Effective ◽  
Solubility Parameters ◽  
Hansen Solubility Parameters ◽  
Lower Reactivity ◽  
Functionalization Of Carbon Nanotubes ◽  
The Many ◽  
Oxygenated Functional Groups

The functionalization of carbon nanotubes (CNTs) plays a key role in their solubilization and compatibility for many applications. Among the many possible ways to functionalize CNTs, the creation of an Si–O–C bond is crucial for the formation of silicone composites. Catalyst-mediated silylesterification is useful in creating Si–O–C bonds because it is cost-effective and uses a hydrosilane precursor of lower reactivity than that of chlorosilane. However, it was previously demonstrated that two important silylesterification catalysts (zinc chloride and Karstedt’s catalyst) exhibit different selectivity for oxidized functional groups that are present on the surface of CNTs after oxidative acid treatment. This report details the selective modification of CNTs with various oxygenated functional groups (aromatic and nonaromatic alcohols, carboxylic acids, ethers, and ketones) using diazonium chemistry. Modified CNTs were used to assess the specifity of zinc chloride and Karstedt’s catalyst for oxygenated functional groups during a silylesterification reaction. Karstedt’s catalyst appeared to be widely applicable, allowing for the silylesterification of all of the aforementioned oxygenated functional groups. However, it showed lower efficacy for ethers and ketones. By contrast, zinc chloride was found to be very specific for nonaromatic carboxylic acids. This study also examined the Hansen solubility parameters of modified CNTs.

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