scholarly journals Studies on the synthesis of peptides containing dehydrovaline and dehydroisoleucine based on copper-mediated enamide formation

2016 ◽  
Vol 12 ◽  
pp. 564-570 ◽  
Author(s):  
Franziska Gille ◽  
Andreas Kirschning
Keyword(s):  
Coupling Reaction ◽  
Cross Coupling ◽  
Protecting Group ◽  
Peptide Fragments ◽  
Reaction Conditions ◽  
Peptide Formation ◽  
Cross Coupling Reaction ◽  
Vinyl Iodide ◽  
Acyl Amide ◽  
Optimized Conditions

The preparation of peptide fragments containing dehydrovaline and dehydroisoleucine moieties present in the antibiotic myxovalargin is reported. Peptide formation is based on a copper-mediated C–N cross-coupling protocol between an acyl amide and a peptidic vinyl iodide. The presence of a neighboring arginine in the vinyl iodide posed a challenge with respect to the choice of the protecting group and the reaction conditions. It was found that ornithine – a suitable precursor – is better suited than arginine for achieving good yields for the C–N cross-coupling reaction. The optimized conditions were utilized for the synthesis of peptides 32, 33, 39 and 40 containing a neighboring ornithine as well as for the tripeptide 44 containing dehydroisoleucine with the correct stereochemistry.

scholarly journals 2-(3-Cyanopropyldimethylsilyl)ethyl as a Polar Sulfur Protecting Group

Synthesis ◽  
2019 ◽  
Vol 51 (22) ◽  
pp. 4153-4164
Author(s):  
Linda M. Bannwart ◽  
Pascal S. Rieder ◽  
Marcel Mayor
Keyword(s):  
Coupling Reaction ◽  
Cross Coupling ◽  
Thiol Group ◽  
Organosulfur Compounds ◽  
Coupling Reactions ◽  
Protecting Group ◽  
Reaction Conditions ◽  
Cross Coupling Reactions ◽  
Cross Coupling Reaction ◽  
The Stability

Organosulfur compounds are ubiquitous in synthetic chemistry, biology and materials chemistry. The reactivity of free sulfhydryls requires their masking in many synthetic strategies. To facilitate the isolation of protected thiols by chromatography, we propose 2-(3-cyanopropyldimethylsilyl)ethyl as a polar protecting group analogue of 2-(trimethylsilyl)ethyl. The masked thiophenol is obtained in two synthetically complementing ways. Either an existing thiophenol is protected, or the protected thiol group is introduced by a cross-coupling reaction. In both cases the required reagents are readily available from inexpensive starting materials. Thiol protection and thiol introduction both tolerate a large variety of functional groups and substitution patterns, and the protected thiophenols are stable toward a broad range of reaction conditions. The stability of the protected derivatives in cross-coupling reactions and the mild reaction conditions for the release of the protecting group further emphasizes the potential of the methodology.

Regiospecific Palladium-Catalyzed Cross-Coupling Reactions Using the Operational Equivalent of 1,3-Dilithiopropyne

Synthesis ◽  
2020 ◽  
Vol 52 (16) ◽  
pp. 2387-2394 ◽  
Author(s):  
Jorge A. Cabezas ◽  
Natasha Ferllini
Keyword(s):  
Coupling Reaction ◽  
Cross Coupling ◽  
Coupling Reactions ◽  
Terminal Alkyne ◽  
Copper Iodide ◽  
Reaction Conditions ◽  
Cross Coupling Reactions ◽  
Cross Coupling Reaction ◽  
Palladium Catalyzed ◽  
High Yields

A regiospecific palladium-catalyzed cross-coupling reaction using the operational equivalent of the dianion 1,3-dilithiopropyne, with aromatic iodides is reported. This reaction gives high yields of 1-propyn-1-yl-benzenes and 2-(propyn-1-yl)thiophenes in the presence of catalytic amounts of palladium(0) or (II) and stoichiometric amounts of copper iodide. No terminal alkyne or allene isomers were detected. Reaction conditions were very mild and several functional groups were tolerated.

scholarly journals A new approach to silicon rhodamines by Suzuki–Miyaura coupling – scope and limitations

2019 ◽  
Vol 15 ◽  
pp. 2569-2576 ◽  
Author(s):  
Thines Kanagasundaram ◽  
Antje Timmermann ◽  
Carsten S Kramer ◽  
Klaus Kopka
Keyword(s):  
Free Acid ◽  
Coupling Reaction ◽  
Cross Coupling ◽  
Stimulated Emission ◽  
New Approach ◽  
Cross Coupling Reaction ◽  
Optimal Coupling ◽  
Sensor Molecules ◽  
Optimized Conditions ◽  
Coupling Partner

Background: Silicon rhodamines are of particular interest because of their advantageous dye properties (fluorescence- and biostability, quantum efficiency, tolerance to photobleaching). Therefore, silicon rhodamines find frequent application in STED (stimulated emission depletion) microscopy, as sensor molecules for, e.g., ions and as fluorophores for the optical imaging of tumors. Different strategies were already employed for their synthesis. Because of just three known literature examples in which Suzuki–Miyaura cross couplings gave access to silicon rhodamines in poor to moderate yields, we wanted to improve these first valuable experimental results. Results: The preparation of the xanthene triflate was enhanced and several boron sources were screened to find the optimal coupling partner. After optimization of the palladium catalyst, different substituted boroxines were assessed to explore the scope of the Pd-catalyzed cross-coupling reaction. Conclusions: A number of silicon rhodamines were synthesized under the optimized conditions in up to 91% yield without the necessity of HPLC purification. Moreover, silicon rhodamines functionalized with free acid moieties are directly accessible in contrast to previously described methods.

Alkenyl- and aryl[2-(hydroxymethyl)phenyl]dimethylsilanes: Tetraorganosilanes for the practical cross-coupling reaction

2006 ◽  
Vol 78 (2) ◽  
pp. 435-440 ◽  
Author(s):  
Yoshiaki Nakao ◽  
Akhila K. Sahoo ◽  
Hidekazu Imanaka ◽  
Akira Yada ◽  
Tamejiro Hiyama
Keyword(s):  
Functional Groups ◽  
Coupling Reaction ◽  
Cross Coupling ◽  
Hydroxyl Group ◽  
Axial Position ◽  
Silyl Ether ◽  
Intramolecular Coordination ◽  
Reaction Conditions ◽  
Diverse Range ◽  
Cross Coupling Reaction

Readily accessible and highly stable alkenyl- and aryl[2-(hydroxymethyl)phenyl]dimethylsilanes cross-couple with various aryl and alkenyl halides under mild reaction conditions employing K2CO3 as a base at 35-80 °C. The reaction tolerates a diverse range of functional groups including silyl protections. The silicon residue, cyclic silyl ether, is readily recovered and reused on a gram-scale synthesis. Intramolecular coordination of a proximal hydroxyl group is considered to efficiently form pentacoordinated silicates having a transferable group at an axial position.

Optimizing chemical reaction conditions using deep learning: a case study for the Suzuki–Miyaura cross-coupling reaction

2020 ◽  
Vol 7 (16) ◽  
pp. 2269-2277
Author(s):  
Zunyun Fu ◽  
Xutong Li ◽  
Zhaohui Wang ◽  
Zhaojun Li ◽  
Xiaohong Liu ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Deep Learning ◽  
Coupling Reaction ◽  
Cross Coupling ◽  
Quantum Mechanical ◽  
Reaction Conditions ◽  
Cross Coupling Reaction ◽  
Deep Learning Model ◽  
Optimal Reaction

Deep learning was used to optimize chemical reactions with the quantum mechanical properties of chemical contexts and reaction conditions as inputs. The trained deep learning model determines optimal reaction conditions by in silico exploration of accessible reaction space.

An investigation of palladium-catalyzed Stille-type cross-coupling of nitroarenes in perylenediimide series

2022 ◽  
Author(s):  
Aline MAKHLOUTAH ◽  
Danylo Hatych ◽  
Thomas CHARTIER ◽  
Lou ROCARD ◽  
Antoine Goujon ◽  
...  
Keyword(s):  
Coupling Reaction ◽  
Cross Coupling ◽  
Electronic Nature ◽  
Type Reaction ◽  
Cross Coupling Reaction ◽  
Palladium Catalyzed ◽  
Optimized Conditions

We report herein an unprecedented palladium-catalyzed cross-coupling reaction between mononitro-perylenediimide (PDI) and various arylstannanes. Optimized conditions developed with this Stille-type reaction allow the grafting of (hetero)aryls of various electronic nature...

scholarly journals A convenient route to symmetrically and unsymmetrically substituted 3,5-diaryl-2,4,6-trimethylpyridines via Suzuki–Miyaura cross-coupling reaction

2016 ◽  
Vol 12 ◽  
pp. 835-845 ◽  
Author(s):  
Dariusz Błachut ◽  
Joanna Szawkało ◽  
Zbigniew Czarnocki
Keyword(s):  
Coupling Reaction ◽  
Cross Coupling ◽  
High Yield ◽  
Reaction Conditions ◽  
Arylboronic Acids ◽  
Cross Coupling Reaction ◽  
Convenient Route

A series of differently substituted 3,5-diaryl-2,4,6-trimethylpyridines were prepared and characterized using the Suzuki–Miyaura coupling reaction with accordingly selected bromo-derivatives and arylboronic acids. The reaction conditions were carefully optimized allowing high yield of isolated products and also the construction of unsymmetrically substituted diarylpyridines, difficult to access by other methods.

Dimerization of Aromatic Compounds Using Palladium-Carbon-Catalyzed Suzuki–Miyaura Cross-Coupling by One-Pot Synthesis

Synlett ◽  
2018 ◽  
Vol 29 (06) ◽  
pp. 779-784 ◽  
Author(s):  
Guoliang Chen ◽  
Fangyu Du ◽  
Qifan Zhou ◽  
Dongdong Liu ◽  
Ting Fang ◽  
...  
Keyword(s):  
Aromatic Compounds ◽  
Functional Group ◽  
Coupling Reaction ◽  
Cross Coupling ◽  
Potassium Acetate ◽  
Carbon Catalyst ◽  
Reaction Conditions ◽  
One Pot ◽  
Cross Coupling Reaction ◽  
High Yields

The aromatic dimers play a significant role in many aspects. Herein, we report a simple palladium-carbon catalyst that is highly effective for the dimerization of brominated aromatic compounds under mild conditions using abundant brominated aromatic compounds, bis(pinacolate)diboron and potassium acetate by a ‘one-pot’ method. This process, which we believe proceeds via a Suzuki–Miyaura cross-coupling reaction mechanism, allows access to a variety of aromatic compounds under mild reaction conditions and has a good functional group tolerance with moderate to high yields.

scholarly journals Cyclopentadithiophene polymers synthesised via Suzuki-Miyaura polymerisation of MIDA boronate esters

2020 ◽  
Vol 1 ◽  
Author(s):  
Josue Ayuso-Carrillo
Keyword(s):  
Conjugated Polymers ◽  
Organic Electronics ◽  
Coupling Reaction ◽  
Cross Coupling ◽  
Reaction Conditions ◽  
Boronate Esters ◽  
Boronate Ester ◽  
Cross Coupling Reaction ◽  
Synthetic Routes ◽  
Methyliminodiacetic Acid

AbstractCyclopentadithiophene (CPDT), a Csp3-bridged bithiophene heteroaromatic unit, displays interesting properties when it is embedded in the repeating units of π-conjugated polymers, and they are applied in organic electronics devices. Common synthetic routes to CPDT-derived polymers rely on toxic methodologies whilst alternative non-toxic strategies such as the Suzuki-Miyaura reaction have been less studied. In this report we demonstrate that the use of a N-methyliminodiacetic acid (MIDA) boronate ester-derived CPDT monomer allows the efficient formation of poly(cyclopentadithiophene) homopolymer under Suzuki-Miyaura cross-coupling reaction conditions. Thus, the use of MIDA boronate esters might be extended to other organic units to design and construct a plethora of π-conjugated polymers.

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