scholarly journals Oxidative Photocatalytic Homo- and Cross-Coupling of Phenols: Non-Enzymatic, Catalytic Method for Coupling Tyrosine

2020 ◽  
Author(s):  
Kyle Niederer ◽  
Philip H. Gilmartin ◽  
Marisa Kozlowski
Keyword(s):  
High Selectivity ◽  
Cross Coupling ◽  
The Other ◽  
Nucleophilic Attack ◽  
Coupling Reactions ◽  
Catalytic Method ◽  
Cross Coupling Reactions ◽  
Oxidation Potentials ◽  
Coupling Partner ◽  
Radical Form

The first, oxidative photocatalytic method for phenol-phenol homo-coupling and cross-coupling is described and isolated yields of up to 97% are obtained. Measured oxidation potentials and computed nucleophilicity parameters are consistent with a nucleophilic attack of one partner onto the oxidized radical form of the other partner. Understanding of this model permitted development of cross-coupling reactions between nucleophilic phenols/arenes and easily oxidized phenols in high selectivity and efficiency. A highlight of this method is that one equivalent of each coupling partner is utilized. Building on these findings, the first non-enzymatic, catalytic method for coupling tyrosine was developed.

scholarly journals Oxidative Photocatalytic Homo- and Cross-Coupling of Phenols: Non-Enzymatic, Catalytic Method for Coupling Tyrosine

2020 ◽  
Author(s):  
Kyle Niederer ◽  
Philip H. Gilmartin ◽  
Marisa Kozlowski
Keyword(s):  
High Selectivity ◽  
Cross Coupling ◽  
The Other ◽  
Nucleophilic Attack ◽  
Coupling Reactions ◽  
Catalytic Method ◽  
Cross Coupling Reactions ◽  
Oxidation Potentials ◽  
Coupling Partner ◽  
Radical Form

The first, oxidative photocatalytic method for phenol-phenol homo-coupling and cross-coupling is described and isolated yields of up to 97% are obtained. Measured oxidation potentials and computed nucleophilicity parameters are consistent with a nucleophilic attack of one partner onto the oxidized radical form of the other partner. Understanding of this model permitted development of cross-coupling reactions between nucleophilic phenols/arenes and easily oxidized phenols in high selectivity and efficiency. A highlight of this method is that one equivalent of each coupling partner is utilized. Building on these findings, the first non-enzymatic, catalytic method for coupling tyrosine was developed.

scholarly journals Pyridine sulfinates as general nucleophilic coupling partners in palladium-catalyzed cross-coupling reactions with aryl halides

2017 ◽  
Vol 8 (6) ◽  
pp. 4437-4442 ◽  
Author(s):  
Tim Markovic ◽  
Benjamin N. Rocke ◽  
David C. Blakemore ◽  
Vincent Mascitti ◽  
Michael C. Willis
Keyword(s):  
Cross Coupling ◽  
Aryl Halides ◽  
Coupling Reactions ◽  
Cross Coupling Reactions ◽  
Palladium Catalyzed ◽  
Coupling Partner

Pyridine sulfinates are stable and straightforward to prepare nucleophilic coupling partners for palladium catalyzed cross-coupling reactions with aryl and heteroaryl halides. The scope with respect to the halides coupling partner is considerable, and allows the preparation of a broad range of linked pyridines.

scholarly journals Non-Symmetrical Bis-Azine Biaryls from Chloroazines: A Strategy Using Phosphorus Ligand-Coupling

2019 ◽  
Author(s):  
Benjamin T. Boyle ◽  
Michael C. Hilton ◽  
Andrew McNally
Keyword(s):  
Cross Coupling ◽  
Coupling Reactions ◽  
One Pot ◽  
Cross Coupling Reactions ◽  
Alternative Approach ◽  
Metal Catalyzed ◽  
Traditional Approaches ◽  
Coupling Partner ◽  
Coupling Sequence

Distinct approaches to synthesize bis-azine biaryls are in demand as these compounds have multiple applications in the chemical sciences and are challenging targets for metal-catalyzed cross-coupling reactions. Most approaches focus on developing new reagents as the formal nucleophilic coupling partner that can function in metal-catalyzed processes. We present an alternative approach using pyridine and diazine phosphines as nucleophilic partners and chloroazines where the heterobiaryl bond is formed via a tandem S<sub><i>N</i></sub>Ar-phosphorus ligand-coupling sequence. The heteroaryl phosphines are prepared from chloroazines and are bench stable solids. Using this strategy, a range of bis-azine biaryls can be formed from abundant chloroazines that would be challenging using traditional approaches and a one-pot cross-electrophile coupling of two chloroazines is feasible.

scholarly journals Non-Symmetrical Bis-Azine Biaryls from Chloroazines: A Strategy Using Phosphorus Ligand-Coupling

2019 ◽  
Author(s):  
Benjamin T. Boyle ◽  
Michael C. Hilton ◽  
Andrew McNally
Keyword(s):  
Cross Coupling ◽  
Coupling Reactions ◽  
One Pot ◽  
Cross Coupling Reactions ◽  
Alternative Approach ◽  
Metal Catalyzed ◽  
Traditional Approaches ◽  
Coupling Partner ◽  
Coupling Sequence

Distinct approaches to synthesize bis-azine biaryls are in demand as these compounds have multiple applications in the chemical sciences and are challenging targets for metal-catalyzed cross-coupling reactions. Most approaches focus on developing new reagents as the formal nucleophilic coupling partner that can function in metal-catalyzed processes. We present an alternative approach using pyridine and diazine phosphines as nucleophilic partners and chloroazines where the heterobiaryl bond is formed via a tandem S<sub><i>N</i></sub>Ar-phosphorus ligand-coupling sequence. The heteroaryl phosphines are prepared from chloroazines and are bench stable solids. Using this strategy, a range of bis-azine biaryls can be formed from abundant chloroazines that would be challenging using traditional approaches and a one-pot cross-electrophile coupling of two chloroazines is feasible.

Synthesis of 2-Substituted 6-(Hydroxymethyl)purine Bases and Nucleosides

2005 ◽  
Vol 70 (10) ◽  
pp. 1669-1695 ◽  
Author(s):  
Peter Šilhár ◽  
Radek Pohl ◽  
Ivan Votruba ◽  
Michal Hocek
Keyword(s):  
Adenosine Deaminase ◽  
Cross Coupling ◽  
The Other ◽  
Coupling Reactions ◽  
Purine Derivatives ◽  
Cytostatic Effect ◽  
Purine Bases ◽  
Cross Coupling Reactions ◽  
Zinc Iodide

A facile and efficient methodology of the synthesis of 6-(hydroxymethyl)purine derivatives (bases and nucleosides) was developed based on Pd-catalyzed cross-coupling reactions of 6-halopurines or N-protected 2-amino-6-halopurines with (benzoyloxymethyl)zinc iodide followed by deprotection. Regioselective hydroxymethylations of 2,6-dihalopurines were also studied and used for the synthesis of 2-chloro-6-(hydroxymethyl)- or 2,6-bis(hydroxymethyl)purines. The 6-(hydroxymethyl)purine ribonucleoside 5f exerted high cytostatic effect and moderate inhibition of adenosine deaminase, while all the other derivatives were much less effective or entirely inactive.

scholarly journals Recent Applications of Pd-Catalyzed Suzuki-Miyaura and Buchwald-Hartwig Couplings in Pharmaceutical Process Chemistry.

2021 ◽  
Author(s):  
Balaram S. Takale ◽  
Fan Yi Kong ◽  
Ruchita R. Thakore
Keyword(s):  
Drug Development ◽  
Large Scale ◽  
Cross Coupling ◽  
The Other ◽  
Coupling Reactions ◽  
Complex Molecules ◽  
Pharmaceutical Ingredients ◽  
The Core ◽  
Cross Coupling Reactions ◽  
Process Chemistry

Cross coupling reactions have changed the way complex molecules are synthesized. In particular, Suzuki-Miyaura and Buchwald-Hartwig amination reactions have given opportunities to elegantly make pharmaceutical ingredients. Indeed, these reactions are forefront at both the stages of drug development, medicinal chemistry, and process chemistry. On one hand, these reactions have given medicinal chemists a tool to derivatize the core molecule to arrive at scaffold rapidly. On the other hand, these cross couplings have offered the process chemists a smart tool to synthesize the development candidates safely, quickly, and efficiently. Generally, the application of cross coupling reactions is broad, and this review will specifically focus on their real (pharma) world applications in large scale synthesis those appeared in last two years.

scholarly journals Palladium-catalysed cross-coupling reaction of ultra-stabilised 2-aryl-1,3-dihydro-1H-benzo[d]1,3,2-diazaborole compounds with aryl bromides: A direct protocol for the preparation of unsymmetrical biaryls

2014 ◽  
Vol 10 ◽  
pp. 1107-1113 ◽  
Author(s):  
Siphamandla Sithebe ◽  
Ross S Robinson
Keyword(s):  
Coupling Reaction ◽  
Cross Coupling ◽  
The Other ◽  
Coupling Reactions ◽  
Arylboronic Acids ◽  
Cross Coupling Reactions ◽  
Aryl Bromides ◽  
Cross Coupling Reaction ◽  
Fluorescence Characteristics ◽  
Significant Interest

There has been a significant interest in organoboron compounds such as arylboronic acids, arylboronate esters and potassium aryltrifluoroborate salts because they are versatile coupling partners in metal-catalysed cross-coupling reactions. On the other hand, their nitrogen analogues, namely, 1,3,2-benzodiazaborole-type compounds have been studied extensively for their intriguing absorption and fluorescence characteristics. Here we describe the first palladium-catalysed Suzuki–Miyaura cross-coupling reaction of easily accessible and ultra-stabilised 2-aryl-1,3-dihydro-1H-benzo[d]1,3,2-diazaborole derivatives with various aryl bromides. Aryl bromides bearing electron-withdrawing, electron-neutral and electron-donating substituents are reacted under the catalytic system furnishing unsymmetrical biaryl products in isolated yields of up to 96% in only 10 minutes.

scholarly journals Titanium-mediated reductive cross-coupling reactions of imines with terminal alkynes: An efficient route for the synthesis of stereodefined allylic amines

2013 ◽  
Vol 9 ◽  
pp. 621-627 ◽  
Author(s):  
Kebin Mao ◽  
Guoqin Fan ◽  
Yuanhong Liu ◽  
Shi Li ◽  
Xu You ◽  
...  
Keyword(s):  
Silica Gel ◽  
Column Chromatography ◽  
Cross Coupling ◽  
Coupling Reactions ◽  
Terminal Alkynes ◽  
Allylic Amines ◽  
Cross Coupling Reactions ◽  
Efficient Route ◽  
Coupling Partner

Low-valency titanium species, generated in situ by using Ti(OiPr)4/2 c-C5H9MgCl reagent, react with imines to give a titanium-imine complex that can couple with terminal alkynes to provide azatitanacyclopentenes with excellent regioselectivity. Stereodefined allylic amines are obtained in good yields after hydrolysis or iodonolysis of the corresponding azatitanacyclopentenes. When ethynylcyclopropane is used as the coupling partner to react with imines in this reaction, the initially generated allylic amine undergoes an unexpected 1,3-amino migration on silica gel during the column chromatography.

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