scholarly journals Enantioselective Carboetherification/Hydrogenation for the Synthesis of Amino Alcohols via a Catalytically-Formed Chiral Auxiliary

2020 ◽  
Author(s):  
Luca Buzzetti ◽  
Mikus Purins ◽  
Phillip D. G. Greenwood ◽  
Jerome Waser
Keyword(s):  
Drug Discovery ◽  
Asymmetric Catalysis ◽  
Chemical Reactions ◽  
Building Blocks ◽  
Amino Alcohols ◽  
Chiral Auxiliary ◽  
Alternative Strategy ◽  
Chiral Auxiliaries ◽  
Palladium Catalyzed ◽  
Fast Access

Chiral auxiliaries and asymmetric catalysis are the workhorses of enantioselective transformations, but they still remain limited either in terms of efficiency or generality. Herein, we present an alternative strategy for controlling the stereoselectivity of chemical reactions. Asymmetric catalysis is used to install a transient chiral auxiliary starting from achiral precursors, which then directs diastereoselective reactions. We apply this strategy to a palladium-catalyzed carboetherification/hydrogenation sequence on propargylic amines, providing fast access to enantioenriched chiral amino alcohols, important building blocks for medicinal chemistry and drug discovery. All stereoisomers of the product could be accessed by the choice of ligand and substituent on the propargylic amine, leading to a stereodivergent process.

scholarly journals Enantioselective Carboetherification/Hydrogenation for the Synthesis of Amino Alcohols via a Catalytically-Formed Chiral Auxiliary

2020 ◽  
Author(s):  
Luca Buzzetti ◽  
Mikus Purins ◽  
Phillip D. G. Greenwood ◽  
Jerome Waser
Keyword(s):  
Drug Discovery ◽  
Asymmetric Catalysis ◽  
Chemical Reactions ◽  
Building Blocks ◽  
Amino Alcohols ◽  
Chiral Auxiliary ◽  
Alternative Strategy ◽  
Chiral Auxiliaries ◽  
Palladium Catalyzed ◽  
Fast Access

Chiral auxiliaries and asymmetric catalysis are the workhorses of enantioselective transformations, but they still remain limited either in terms of efficiency or generality. Herein, we present an alternative strategy for controlling the stereoselectivity of chemical reactions. Asymmetric catalysis is used to install a transient chiral auxiliary starting from achiral precursors, which then directs diastereoselective reactions. We apply this strategy to a palladium-catalyzed carboetherification/hydrogenation sequence on propargylic amines, providing fast access to enantioenriched chiral amino alcohols, important building blocks for medicinal chemistry and drug discovery. All stereoisomers of the product could be accessed by the choice of ligand and substituent on the propargylic amine, leading to a stereodivergent process.

scholarly journals Palladium-Catalyzed Functionalization of Olefins and Alkynes: From Oxyalkynylation to Tethered Dynamic Kinetic Asymmetric Transformations (DYKAT)

Synlett ◽  
2020 ◽  
Author(s):  
Stefano Nicolai ◽  
Ugo Orcel ◽  
Bastian Muriel ◽  
Phillip D. G. Greenwood ◽  
Luca Buzzetti ◽  
...  
Keyword(s):  
Organic Synthesis ◽  
Amino Alcohols ◽  
Chiral Auxiliary ◽  
Allylic Alcohols ◽  
Personal Account ◽  
Allylic Amines ◽  
Asymmetric Transformations ◽  
Palladium Catalyzed ◽  
Asymmetric Transformation

AbstractThis review presents an account of the palladium-catalyzed functionalizations of alkenes and alkynes developed at the Laboratory of Catalysis and Organic Synthesis (LCSO). Starting from the intramolecular oxy- and aminoalkynylation of alkenes, tethered methods were then developed to functionalize allylic amines and alcohols, as well as propargylic amines. Finally, a new dynamic kinetic asymmetric transformation was developed based on the use of a ‘one-arm’ Trost-type ligand, giving access to enantiopure amino alcohols. Each section is a personal account by the researcher(s) who performed the work.1 Introduction,2 Oxy- and Aminoalkynylation of Olefins,3 In Situ Tethering Strategies for the Synthesis of Vicinal Amino Alcohols and Diamines,4 Carboamination of Allylic Alcohols,5 Carbooxygenation of Propargylic Amines,6 Enantioselective Carboetherification/Hydrogenation via a Catalytically Formed Chiral Auxiliary,7 Conclusion

Stereospecific, Palladium-catalyzed C(sp3)–H Alkenylation and Alkynylation of a Proline Derivative Enabled by 8-Aminoquinoline as a Directing Group

2020 ◽  
Author(s):  
Aleksandra Balliu ◽  
Aaltje Roelofje Femmigje Strijker ◽  
Michael Oschmann ◽  
Monireh Pourghasemi Lati ◽  
Oscar Verho
Keyword(s):  
Carboxylic Acid ◽  
Building Blocks ◽  
Wide Range ◽  
Palladium Catalyzed ◽  
Directing Group ◽  
High Yields ◽  
Vinyl Iodides ◽  
Initial Results

<p>In this preprint, we present our initial results concerning a stereospecific Pd-catalyzed protocol for the C3 alkenylation and alkynylation of a proline derivative carrying the well utilized 8‑aminoquinoline directing group. Efficient C–H alkenylation was achieved with a wide range of vinyl iodides bearing different aliphatic, aromatic and heteroaromatic substituents, to furnish the corresponding C3 alkenylated products in good to high yields. In addition, we were able show that this protocol can also be used to install an alkynyl group into the pyrrolidine scaffold, when a TIPS-protected alkynyl bromide was used as the reaction partner. Furthermore, two different methods for the removal of the 8-aminoquinoline auxiliary are reported, which can enable access to both <i>cis</i>- and <i>trans</i>-configured carboxylic acid building blocks from the C–H alkenylation products.</p>

An Overview of the One-pot Synthesis of Imidazolines

2020 ◽  
Vol 24 (20) ◽  
pp. 2341-2355
Author(s):  
Thaipparambil Aneeja ◽  
Sankaran Radhika ◽  
Mohan Neetha ◽  
Gopinathan Anilkumar
Keyword(s):  
Asymmetric Catalysis ◽  
Organic Compounds ◽  
Ring Opening ◽  
Ecological Impact ◽  
Chiral Auxiliary ◽  
One Pot ◽  
One Pot Synthesis ◽  
The One ◽  
Synthetic Intermediate ◽  
Heterocyclic Moiety

One-pot syntheses are a simple, efficient and easy methodology, which are widely used for the synthesis of organic compounds. Imidazoline is a valuable heterocyclic moiety used as a synthetic intermediate, chiral auxiliary, chiral catalyst and a ligand for asymmetric catalysis. Imidazole is a fundamental unit of biomolecules that can be easily prepared from imidazolines. The one-pot method is an impressive approach to synthesize organic compounds as it minimizes the reaction time, separation procedures, and ecological impact. Many significant one-pot methods such as N-bromosuccinimide mediated reaction, ring-opening of tetrahydrofuran, triflic anhydrate mediated reaction, etc. were reported for imidazoline synthesis. This review describes an overview of the one-pot synthesis of imidazolines and covers literature up to 2020.

Novel Chiral Ligands for Palladium-catalyzed Asymmetric Allylic Alkylation/ Asymmetric Tsuji-Trost Reaction: A Review

2019 ◽  
Vol 23 (11) ◽  
pp. 1168-1213 ◽  
Author(s):  
Samar Noreen ◽  
Ameer Fawad Zahoor ◽  
Sajjad Ahmad ◽  
Irum Shahzadi ◽  
Ali Irfan ◽  
...  
Keyword(s):  
Asymmetric Catalysis ◽  
Enantioselective Synthesis ◽  
Chiral Ligands ◽  
Allylic Alkylation ◽  
Research Groups ◽  
Asymmetric Allylic Alkylation ◽  
Catalytic Potential ◽  
Long Time ◽  
Palladium Catalyzed ◽  
Alkylation Reactions

Background: Asymmetric catalysis holds a prestigious role in organic syntheses since a long time and chiral inductors such as ligands have been used to achieve the utmost desired results at this pitch. The asymmetric version of Tsuji-Trost allylation has played a crucial role in enantioselective synthesis. Various chiral ligands have been known for Pdcatalyzed Asymmetric Allylic Alkylation (AAA) reactions and exhibited excellent catalytic potential. The use of chiral ligands as asymmetric inductors has widened the scope of Tsuji-Trost allylic alkylation reactions. Conclusion: Therefore, in this review article, a variety of chiral inductors or ligands have been focused for palladium catalyzed asymmetric allylic alkylation (Tsuji-Trost allylation) and in this regard, recently reported literature (2013-2017) has been described. The use of ligands causes the induction of enantiodiscrimination to the allylated products, therefore, the syntheses of various kinds of ligands have been targeted by many research groups to employ in Pd-catalyzed AAA reactions.

Application of Nitrogen Heterocyclic Carbenes in Organocatalysis

2020 ◽  
Vol 09 ◽  
Author(s):  
Minita Ojha ◽  
R. K. Bansal
Keyword(s):  
Asymmetric Catalysis ◽  
Building Blocks ◽  
Structural Features ◽  
Heterocyclic Carbenes ◽  
Stetter Reaction ◽  
Metal Pollutants ◽  
Synthetic Strategy ◽  
Wide Range ◽  
Benzoin Condensation ◽  
Nitrogen Heterocyclic

Background: During the last two decades, horizon of research in the field of Nitrogen Heterocyclic Carbenes (NHC) has widened remarkably. NHCs have emerged as ubiquitous species having applications in a broad range of fields, including organocatalysis and organometallic chemistry. The NHC-induced non-asymmetric catalysis has turned out to be a really fruitful area of research in recent years. Methods: By manipulating structural features and selecting appropriate substituent groups, it has been possible to control the kinetic and thermodynamic stability of a wide range of NHCs, which can be tolerant to a variety of functional groups and can be used under mild conditions. NHCs are produced by different methods, such as deprotonation of Nalkylhetrocyclic salt, transmetallation, decarboxylation and electrochemical reduction. Results: The NHCs have been used successfully as catalysts for a wide range of reactions making a large number of building blocks and other useful compounds accessible. Some of these reactions are: benzoin condensation, Stetter reaction, Michael reaction, esterification, activation of esters, activation of isocyanides, polymerization, different cycloaddition reactions, isomerization, etc. The present review includes all these examples published during the last 10 years, i.e. from 2010 till date. Conclusion: The NHCs have emerged as versatile and powerful organocatalysts in synthetic organic chemistry. They provide the synthetic strategy which does not burden the environment with metal pollutants and thus fit in the Green Chemistry.

scholarly journals Fluorinated Iron(ii) clathrochelate units in metalorganic based copolymers: improved porosity, iodine uptake, and dye adsorption properties

RSC Advances ◽  
2021 ◽  
Vol 11 (25) ◽  
pp. 14986-14995
Author(s):  
Suchetha Shetty ◽  
Noorullah Baig ◽  
Atikur Hassan ◽  
Saleh Al-Mousawi ◽  
Neeladri Das ◽  
...  
Keyword(s):  
Dye Adsorption ◽  
Coupling Reaction ◽  
Cross Coupling ◽  
Building Blocks ◽  
Adsorption Properties ◽  
Iodine Uptake ◽  
Cross Coupling Reaction ◽  
Palladium Catalyzed

We report the synthesis of metalorganic copolymers made from the palladium catalyzed Sonogashira cross-coupling reaction between various iron(ii) clathrochelate building blocks with diethynyl–triptycene and fluorene derivatives.

Data augmentation and transfer learning strategies for reaction prediction in low chemical data regimes

2021 ◽  
Author(s):  
Yun Zhang ◽  
Ling Wang ◽  
Xinqiao Wang ◽  
Chengyun Zhang ◽  
Jiamin Ge ◽  
...  
Keyword(s):  
Organic Chemistry ◽  
Deep Learning ◽  
Drug Discovery ◽  
Research And Development ◽  
Learning Strategies ◽  
Transfer Learning ◽  
Chemical Reactions ◽  
Data Augmentation ◽  
Learning Method ◽  
Reaction Prediction

An effective and rapid deep learning method to predict chemical reactions contributes to the research and development of organic chemistry and drug discovery.

Synthesis of sp3-Enriched β-Fluoro Sulfonyl Chlorides

Synthesis ◽  
2020 ◽  
Author(s):  
Oleksandr O. Grygorenko ◽  
Rustam Gurbanov ◽  
Andriy Sokolov ◽  
Sergey Golovach ◽  
Kostiantyn Melnykov ◽  
...  
Keyword(s):  
Drug Discovery ◽  
Double Bond ◽  
Building Blocks ◽  
Protecting Groups ◽  
Sulfonyl Chlorides ◽  
Wide Range ◽  
Cyclic Compounds

AbstractA three-step approach to the synthesis of sp3-enriched β-fluoro sulfonyl chlorides starting from alkenes is reported. The method was successfully applied to a wide range of acyclic and cyclic substrates, bearing either an exocyclic or an endocyclic double bond. The procedure worked with a wide range of substrates and tolerated a number of functional and protecting groups. Moreover, the target cyclic compounds were obtained as single cis diastereomers on a multigram scale. The title compounds are promising building blocks for drug discovery that can be used to obtain sp3-enriched β-fluoro and α,β-unsaturated sulfonamides.

scholarly journals Synthesis of π-Conjugated Polymers Containing Benzotriazole Units via Palladium-Catalyzed Direct C-H Cross-Coupling Polycondensation for OLEDs Applications

Polymers ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 254
Author(s):  
Dong Han ◽  
Jingwen Li ◽  
Qiang Zhang ◽  
Zewang He ◽  
Zhiwei Wu ◽  
...  
Keyword(s):  
Conjugated Polymers ◽  
Quantum Efficiency ◽  
Cross Coupling ◽  
Building Blocks ◽  
Gravimetric Analysis ◽  
19F Nmr Spectra ◽  
Light Emitting ◽  
Molecular Weights ◽  
Palladium Catalyzed ◽  
Red Luminescence

Four D-π-A conjugated polymers, namely P1–P4, which contain benzotriazole building blocks in their backbone as acceptor, are synthesized via palladium-catalyzed direct C-H cross-coupling polycondensation of 5,6-difluorobenzotriazole with different thiophene derivatives, including 3-octylthiophene, 2,2’-bithiophene, thieno[3,4-b][1,4]dioxine, and 4,4-dioctyl-4H-silolo-[3,2-b:4,5-b’]dithiophene as donor units, respectively. Taking the polymer P1 as an example, the chemical structure of the polymer is demonstrated by 1H and 19F NMR spectra. The optical, electrochemical, and thermal properties of these polymers are assessed by UV–vis absorption and fluorescence spectroscopy, cyclic voltammetry (CV), and thermal gravimetric analysis (TGA), respectively. DFT simulations of all polymers are also performed to understand their physicochemical properties. Furthermore, P1 and P2, which have relatively higher molecular weights and better fluorescent quantum efficiency than those of P3 and P4, are utilized as lighting emitters for organic light-emitting diodes (OLEDs), affording promising green and red luminescence with 0.07% and 0.14% of maximum external quantum efficiency, respectively, based on a device with an architecture of ITO/PEDOT:PSS/PTAA/the polymer emitting layer/TPBi/LiF/Al.

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