Catalytic asymmetric reactions. Medical search. Frequent questions

reported the catalysis of this reaction using a Ti(IV)-BINOL complex in the same year as the Keck group, Keck's publication reported higher enantio- and diastereoselectivity, and did not require the use of 4 Angstrom molecular sieves as in Mikami's procedure or an excess of BINOL as in Tagliavini's procedure. (wikipedia.org)
Non-Noble Metal Catalysis provides an authoritative survey of the field, from fundamental concepts and computational methods to industrial applications and reaction classes. (wiley-vch.de)
Non-Noble Metal Catalysis: Molecular Approaches and Reactions is an indispensable source of up-to-date information for catalytic chemists, organic chemists, industrial chemists, organometallic chemists, and those seeking to broaden their knowledge of catalytic chemistry. (wiley-vch.de)
Supramolecular catalysis, the use of non-covalent forces to affect a catalytic process, can afford the catalyst diversity required to uncover efficient catalysts and further our understanding. (unl.edu)
Perhaps most surprisingly, the presence of a chiral recognition element positioned remote to the site of catalysis can significantly impact the catalytic activity and enantioselectivity. (unl.edu)
Driving asymmetric catalysis with visible light or electricity is of significant value because they represent 'green' and sustainable methods to synthesize non-racemic chiral molecules and in addition offer ample opportunities for chemists to discover new mechanistic scenarios and invent previously. (uni-marburg.de)
3) A simple and robust catalysis scheme that only relies on a single bis-cyclometalated rhodium catalyst (RhS) is introduced to achieve the stereocontrol of bond forming reactions directly from an electronically excited state. (uni-marburg.de)
Detailed kinetic and mechanistic investigations in our group aim to blend the quantitative aspects of chemical engineering together with organic chemistry to achieve a fundamental understanding of complex catalytic reaction networks, particularly in asymmetric catalysis. (imperial.ac.uk)
Homogenous gold catalysis has made significant progress in recent years, but gold has been rarely used in CADA reactions compared with other transition metals. (chemistryviews.org)
Asymmetric catalysis has the potential to provide a more direct and efficient synthetic route compared to traditional resolution methods of constructing P -chiral compounds. (thieme.de)
2. Utility of asymmetric amide-based ligand for asymmetric flow catalysis. (caltech.edu)
Bredig introduced the model reaction methodology to catalytic research, discovered and explored new catalytic phenomena, and discovered and investigated asymmetric catalysis. (sciencehistory.org)

Here, we report that catalytic single-site Co in a well-defined brookite TiO 2 nanorod (210) surface (Co-TiO 2 ) presents turnover frequencies that are among the highest for Co-based heterogeneous catalysts reported to date, reaching 6.6 ± 1.2 and 181.4 ± 28 s −1 at 300 and 400 mV overpotentials, respectively. (nature.com)
1,2] In our latest publications, we reported the highest enantioselectivity for this reaction when using calcium as an environmentally friendly and inexpensive alternative to precious metal catalysts. (findaphd.com)
Carbohydrate-based macrocycles can be enantioselective catalysts in certain reactions. (researchgate.net)
This reaction has a great scope of forming aza-stereocenters which can be tuned by different asymmetric catalysts. (beilstein-journals.org)
Therefore, harsh reaction conditions and the necessity of an external activator like catalysts are common prerequisites for processes involving C-H bond breaking. (beilstein-journals.org)
He has been editor of the book Recoverable and recyclable catalysts (Wiley 2009), of the book "Catalyst Immobilization: Methods and Applications" (Wiley, 2020), and of the book "Organocatalysis -Stereoselective Reactions and Applications in Organic Synthesis" (DeGruyter, 2021) and he is member of the editorial board of Molecules. (selectbiosciences.com)
His research activities include: development of novel synthetic methodologies, stereoselective reactions in water and other alternative, sustainable reaction solvents (such as DES, deep eutectic solvents), design of new chiral catalysts, recyclable organic catalysts, to be used also in flow chemistry processes (catalytic reactors) and in micro(meso)reactors, 3D-printing technologies, synthesis of chiral products of pharmaceutical interest, organophotocatalytic reactions and studies on stereoselective electrochemical organic reactions. (selectbiosciences.com)

The Tagliavini group, which had carried out asymmetric allylation using a similar BINOL-Ti(IV) complex, followed up early successes by synthesizing a variety of enantiopure substituted binaphthyl ligands. (wikipedia.org)
Bis(oxazolines) as Chiral Ligands in Metal-Catalyzed Asymmetric Reactions. (nyu.edu)
This is a significant problem in relation to their catalytic performance, and ligands need to be designed that are able to control or supress these processes. (findaphd.com)
Iron(II) complexes containing ligands with a R2P-P-PR2 unit were synthesized by metathesis reactions. (researchgate.net)
The main advantages of organocatalyzed stereoselective reactions include mild reaction conditions and the use of a sole catalyst without the need of other chiral ligands [4,5] . (beilstein-journals.org)
C 6 H 6 )L] were obtained from the reactions between [RuCl 2 (η 6 -C 6 H 6 )] 2 and the chiral aroylthiourea ligands (L) derived from unprotected D/L-alanine and characterized. (ias.ac.in)
However, phosphorus ( P )-chiral ligands have not been explored as extensively in catalytic reactions as axially chiral, carbon ( C )-chiral, or planar-chiral compounds such as binap, diop, or josiphos. (thieme.de)

The development of a highly enantioselective catalytic oxa-Pictet-Spengler reaction has proven a great challenge for chemical synthesis. (mpg.de)
An efficient catalytic and highly enantioselective protonation of silyl ketene imines is catalyzed by the chiral phosphoric acids TRIP or STRIP in the presence of a stoichiometric amount of methanol as the proton source and silyl acceptor. (organic-chemistry.org)
Chemical Equation Presented) The less problematic acetyl cyanide can be used instead of toxic HCN for the highly enantioselective acyl-Strecker-type reaction. (lookchem.com)

abstract = "Nozaki-Hiyama reactions are powerful CrII-mediated C - C bond-forming reactions conducted under mild conditions that show excellent compatibility with various functional groups. (elsevierpure.com)
Abstract A carbene-catalyzed asymmetric access to chiral β-cyano carboxylic esters is disclosed. (stanford.edu)

In this review, we describe the development of a tridentate bis(oxazolinyl)carbazole ligand for the catalytic asymmetric Nozaki-Hiyama allylation, methallylation, propargylation, and allenylation. (elsevierpure.com)
The reaction of bis-[2-amino-4-pheny1-5-thiazolyl] disulfide with 5-nitro-salicylaldehyde in absolute ethanol resulted in the formation of a new Schiff base ligand H 2 L (1). (scirp.org)
The reaction of the Schiff base ligand with Co(II) and Cu (II) salts in methanol affords the [CoL] and [ClCuHL] complexes. (scirp.org)

Au cours de cet ouvrage, nous nous sommes intéressés à la synthèse de ces unités sous forme énantioenrichie en utilisant la cyclopropanation d'alcènes par catalyse avec des complexes de Rh(II) utilisant des composés diazoïques di-accepteurs comme substrats. (umontreal.ca)
Following the initial development of a method for the catalytic asymmetric cyclopropanation of alkenes using nitro diazoketones, many experimental studies on the mechanism of stereoinduction in this reaction were performed. (umontreal.ca)

Rueping, M , Bootwicha, T & Sugiono, E 2012, ' Continuous-flow catalytic asymmetric hydrogenations: Reaction optimization using FTIR inline analysis ', Beilstein journal of organic chemistry , vol. 8, pp. 300-307. (edu.sa)
Title: "New Catalytic Methods for Pauson-Khand Reactions, Isomerizations and Asymmetric Hydrogenations. (irbbarcelona.org)

The strategic use of a soft Lewis basic thiophosphinoyl group for ketimines is the key to promoting the reaction, and aliphatic ketimines serve as suitable substrates with as little as 3 mol % catalyst loading. (elsevierpure.com)
Keck's early success with stereoselectivity and the simplicity of the catalyst preparation led to many improvements in reaction design, including development of other structural analogs of BINOL, use of stoichiometric additives to enhance the reaction rate, and broadening the scope of the reaction to include substituted stannane nucleophiles. (wikipedia.org)
Two key steps in the allylation reaction involve breakage of the Sn-C bond in the allyl fragment and formation of the O-Sn bond to facilitate reproduction of the Ti(IV) catalyst. (wikipedia.org)
Chan Mo-Yu and coworkers developed an alkylthiosilane accelerator to promote both of these steps, simultaneously increasing the reaction rate and lowering the required catalyst dosages. (wikipedia.org)
Using a modular design and self-assembly, a large scale supramolecular catalyst screening in a catalyst scaffold optimization study of rhodium-catalyzed asymmetric hydrogenation was carried out. (unl.edu)
In these reactions, stereoinduction in the products is achieved by the chiral environment present in the catalyst itself. (beilstein-journals.org)
1) A bis-cyclometalated chiral-at-metal rhodium complex (designated as RhS) in combination with the photoredox catalyst [Ru(bpy)3](PF6)2 enables visible-light-activated asymmetric α-amination and α-alkylation of 2-acyl imidazoles with aryl azides or α-diazo carboxylic esters as radical precursors, respectively (Chapter 3.1). (uni-marburg.de)
All reactive intermediates remain bound to the chiral catalyst thereby providing a robust catalytic scheme (no exclusion of air necessary) with excellent stereoinduction. (uni-marburg.de)
Coordination of the cyclopropane with the chiral catalyst generates the visible-light-absorbing complex, lowers the reduction potential of the cyclopropane, and provides the asymmetric induction and overall stereocontrol. (uni-marburg.de)
Enabled by a mild single electron transfer reduction of directly photoexcited catalyst/substrate complexes, the scope of asymmetric photocycloadditions is extended to simple mono-acceptor-substituted cyclopropanes with the synthesis of previously inaccessible enantioenhanced cyclopentane and cyclopentene derivatives. (uni-marburg.de)
This reaction is highly challenging because of its inherent strong background reaction leading to racemate formation and the high capability of coordination of the nitrogen atom resulting in catalyst deactivation. (rsc.org)
3. Catalytic direct dehydrative amidation by a novel B3NO2 heterocyclic catalyst. (caltech.edu)
The reaction was then performed in various solvents using indium as the catalyst to identify the best condition. (springeropen.com)
It suggests that indium is the best catalyst in aqueous medium for the reaction (Table 2 ). (springeropen.com)
The same reaction was used to optimize the amount of the catalyst. (springeropen.com)

Nowadays, organocatalysis is especially applied to asymmetric synthesis and a huge number of organocatalysts has been introduced in last three decades for the asymmetric synthesis of acyclic, carbocyclic, heterocyclic, and polycyclic molecular architectures with high molecular complexity. (beilstein-journals.org)
In particular, asymmetric organocatalysis plays a pivotal role in the construction of optically active, bioactive, and natural products. (beilstein-journals.org)
After that, he moved to Hong Kong as a postdoctoral researcher in the group of Prof. Jianwei Sun, working on asymmetric organocatalysis. (iciq.es)
We will combine asymmetric organocatalysis and photochemistry, two powerful strategies of modern chemical research. (iciq.es)
PHOTO-CYCLE aims to combine the fellow's experience in allene chemistry and organocatalysis and the host's experience in photo-triggered asymmetric processes to develop otherwise unachievable catalytic asymmetric cascade reactions. (iciq.es)

In organic chemistry, the Keck asymmetric allylation is a chemical reaction that involves the nucleophilic addition of an allyl group to an aldehyde. (wikipedia.org)
The research interests of the members of the Chemical Physics Thematic Research Group are diverse, with groups focusing on high-end laser and NMR spectroscopies, kinetics and modelling of atmospheric chemical reactions, experimental and theoretical biophysical chemistry, polymers at interfaces, and statistical and quantum mechanics. (mcgill.ca)
As a result, most chemists in academia and industry now make use of boronic acids in synthetic chemistry, be it for Suzuki-Miyaura cross-coupling or other reactions. (weltbild.de)
1. Direct enolization chemistry of amide via designed asymmetric cooperative catalytic system. (caltech.edu)

DFT calculations provide insight into the reaction mechanism. (mpg.de)
Based on grand canonical quantum mechanics calculations and the single-site Co atomic structure validated by in situ and ex situ spectroscopic probes, we have established a full description of the catalytic reaction kinetics for Co-TiO 2 as a function of applied potential, revealing an adsorbate evolution mechanism for the OER. (nature.com)
The mechanism can be described as a cascade reaction in two steps: First, an allene is formed by gold(I)-catalyzed dearomatization. (chemistryviews.org)

1,1-Disubstituted alkenes are a challenging class of substrates for the asymmetric hydroboration reaction. (unl.edu)

2. (R)-2-Methyl-CBS-oxazaborolidine is used in the asymmetric reduction of prochiral ketones. (lookchem.com)
Differentiation of the prochiral faces has been met with few successes from either stoichiometric or catalytic approaches. (unl.edu)

The aza-Friedel-Crafts reaction allows an efficient coupling of electron-rich aromatic systems with imines for the facile incorporation of aminoalkyl groups into the aromatic ring. (beilstein-journals.org)

Since the report by Fürstner, the catalytic asymmetric Nozaki-Hiyama reactions have attracted attention because they would allow control over enantioselectivity, thereby further enhancing the versatility of Nozaki-Hiyama reactions. (elsevierpure.com)

This reaction converts almost all enal substrate to a Thiol-click Intermediate, significantly reducing aromatic thiol substrates concentration and suppressing the homo-coupling reaction of enals. (stanford.edu)

The Ru(II)-benzene complexes catalyzed the asymmetric transfer hydrogenation (ATH) of aromatic ketones to their enantiopure secondary alcohols. (ias.ac.in)
The scope of the catalytic system was extended to various aromatic ketones. (ias.ac.in)
The catalytic activity of the present water-soluble Ru-benzene complexes toward enantioselective reduction of ketones was considerably higher than that of p-cymene analogues in water. (ias.ac.in)

The asymmetric organocatalytic hydrogenation of benzoxazines, quinolines, quinoxalines and 3H-indoles in continuous-flow microreactors has been developed. (edu.sa)
Rh-catalyzed asymmetric hydrogenation has emerged as a powerful tool for the manufacturing of chiral pharmaceuticals. (unl.edu)

A catalytic asymmetric synthesis of the key intermediates 4 and 15 for the capnellenols has been achieved through an asymmetric Heck reaction followed by the acetate anion capture process. (elsevierpure.com)
However, steering the reaction course of photo- and/or electrochemically generated reactive intermediates in a stereocontrolled and catalytic fashion is very challenging. (uni-marburg.de)

Our experimental focus is on reaction progress kinetic analysis, a methodology that combines the collection of accurate experimental data via a variety of in-situ tools for continuous reaction monitoring together with kinetic modelling in order to propose and test mechanistic models for reaction networks. (imperial.ac.uk)

In contrast, many of these reported methods involve the use of expensive reagents, hazardous solvents, longer reaction times and tedious workup procedure. (springeropen.com)

List, B. Catalytic Asymmetric Additions of Enol Silanes to in situ Generated Cyclic, Aliphatic N-Acyliminium Ions. (mpg.de)

The Keck asymmetric allylation has many applications to the synthesis of natural products, including (−)-Gloeosporone, Epothilone A, the CD-Subunit of spongistatins, and the C10-C20 Subunit of rhizoxin A, The Keck allylation has also been utilized to form substituted tetrahydropyrans enantioselectively, moieties found in products such as phorboxazole and bryostatin 1. (wikipedia.org)

A visible light catalyzed cyclization of bis(enones) to afford enantiomerically enriched cyclopentane rings, the use of packed-bed reactors in light-driven reactions and a continuous flow approach to access alpha-trifluoromethylthiolated esters and amides starting from commercially available arylacetic acids will be also described, as well as in-flow on water ultrafast organic transformations. (selectbiosciences.com)

Research in the Ward group is concerned with the catalytic applications of main group and early transition metal organometallic and coordination complexes. (findaphd.com)
One of our recent highlights has been the development of chiral calcium complexes for the asymmetric hydroamination of amino-olefins. (findaphd.com)
This thesis presents novel applications of previously in the Meggers group developed chiral-at-metal rhodium complexes to the areas of asymmetric photocatalysis and asymmetric electrosynthesis. (uni-marburg.de)
The reaction of (1) with Co(NO 3 ) 2 ·6H 2 O and CuCl 2 ·2H 2 O in methanol afforded the corresponding metal complexes. (scirp.org)
These metal complexes can be used in catalytic reactions and as models for biological systems. (scirp.org)
The chiral copper complexes were applied to a model asymmetric acylation reaction. (arizona.edu)

For the synthesis of monoareno pentalenes, a carbopalladation cascade reaction between alkynes and gem-dibromoolefins was applied. (researchgate.net)

Harnessing the ambiphilicity of silyl nitronates in a catalytic asymmetric approach to aliphatic β 3 -amino acids. (mpg.de)

Asymmetric heck reaction-anion capture process. (elsevierpure.com)
Furthermore, the above reaction has been successfully applied to an asymmetric Heck reaction -amine capture process. (elsevierpure.com)
Dive into the research topics of 'Asymmetric heck reaction-anion capture process. (elsevierpure.com)

List, B. The Catalytic Asymmetric Intermolecular Prins Reaction. (mpg.de)

As previously demonstrated, the outcome of the reaction depends strongly on the applied alkali metal, solvent, reaction conditions, and substituent pattern. (researchgate.net)

My Research interests focus on studies of complex catalytic organic reactions, with emphasis on application in pharmaceutical processes. (imperial.ac.uk)

Described herein is a dirhodium( II )-catalyzed asymmetric cycloisomerization reaction of azaenyne through a cap-tether synergistic modulation strategy, which represents the first catalytic asymmetric cycloisomerization of azaenyne. (rsc.org)

The reaction proceeds between β,β-disubstituted enals and aromatic thiols involving enantioselective protonation of enal β-carbon. (stanford.edu)

List, B. Catalytic Asymmetric Hydroalkoxylation of C-C Multiple Bonds. (mpg.de)
Overall, five new C-C bonds are formed in this one-pot reaction (pictured in red). (chemistryviews.org)

Reaction monitoring was achieved by using an inline ReactIR flow cell, which allows fast and convenient optimization of reaction parameters. (edu.sa)

Faller's group, whose aforementioned work helped elucidate the chiral amplification of the reaction, also developed the use of diisopropyl tartrate in a chiral poisoning strategy. (wikipedia.org)
However, the structural complexity of heterogeneous electrocatalysts makes it a great challenge to elucidate the surface catalytic sites and OER mechanisms. (nature.com)

Design of an Organocatalytic Asymmetric (4 + 3) Cycloaddition of 2-Indolylalcohols with Dienolsilanes. (mpg.de)
Nous avons démontré l'utilité des dérivés cyclopropaniques énantioenrichis obtenus par ces trois méthodes dans une panoplie de manipulations synthétiques, dont l'addition nucléophile d'amines et de cuprates, la cycloaddition formelle avec un aldéhyde, et la synthèse de dérivés cyclopropaniques importants en chimie médicinale. (umontreal.ca)

In the third part, we reported a class of reactions involving C-H cleavage under mild conditions: Pd II -catalyzed oxidative transformations of enallenes. (diva-portal.org)
The ease of a chemical transformation depends on the thermodynamic instability of a chemical bond owing to its fast cleavage under mild reaction conditions. (beilstein-journals.org)

Asymmetric synthesis of α-chiral hydroxyalkylphosphines via a catalytic, enantioselective reduction of acylphosphines. (lookchem.com)

Creating complex polycyclic molecules from simple building blocks often is challenging and requires many reaction steps. (chemistryviews.org)
Transition-metal-catalyzed C-C coupling reactions, such as the catalytic asymmetric dearomatization (CADA) reaction, are useful tools to synthesize complex molecules efficiently. (chemistryviews.org)
The reaction could be a basis for new syntheses of cyclic and polycyclic molecules. (chemistryviews.org)

The tethered nitrogen atom incorporated into the starting materials enabled easy late-modifications of the centrally and axially chiral products via C-H functionalizations, which further demonstrated the appealing synthetic utilities of this powerful asymmetric cyclization. (rsc.org)
These issues will be discussed with emphasis on synthetic utility and reaction mechanisms. (caltech.edu)
In addition to synthetic utilities, our control of reaction outcomes via in situ substrate modulation and release can likely inspire future reaction development. (stanford.edu)

During his PhD, he worked on the synthesis and reactions of allenes. (iciq.es)

Considering the above observations we carried out a series of reaction using various carbonyl compounds, amines and TMSCN in presence of indium (10 mol%) in water as solvent (Figure 1 ). (springeropen.com)

In the presence of a catalytic amount of [4j](2)Al(III)Cl complex (0.05 equiv), reaction between alpha-isocyanoacetamides (2) and aldehydes (3) afforded the corresponding 5-aminooxazoles (1) in good yields and enantioselectivities. (unboundmedicine.com)
Therefore, Nozaki-Hiyama reactions have been utilized for many total syntheses of complex natural products, but at least two equivalents of Cr II salt are required to complete the reaction because Cr II salt is a one-electron donor. (elsevierpure.com)

This review assembles recent advances in asymmetric aza-Friedel-Crafts reactions mediated by organocatalysts. (beilstein-journals.org)

Another factor is an in situ release of enal substrate from the Thiol-click Intermediate for the desired reaction to proceed effectively. (stanford.edu)

99% ee using a simple reaction setup and mild reaction conditions. (uni-marburg.de)

However, many disadvantages are associated with metal-mediated organic transformations including harsh reaction conditions (e.g., high temperature) and toxic solvents. (beilstein-journals.org)

The classical Strecker reaction is one of the simplest and most economical methods for the synthesis of racemic α-aminonitriles (precursor of α-amino acids) and pharmacologically useful compounds. (springeropen.com)
Strecker reaction [ 1 ], the oldest known synthesis of α-aminonitriles, is one of the most general methods potentially useful for syntheses of amino acids and other bioactive compounds including natural products. (springeropen.com)
In addition, the Strecker reaction represents one of the simplest and most economical methods for the preparation of α-amino acids for both laboratory and industrial scales [ 2 ]. (springeropen.com)

First of all, indium and a number of indium salts have been screened using aniline, benzaldehyde and TMSCN as a model reaction at room temperature. (springeropen.com)

Chemicals and Drugs1

Phenomena and Processes2

Catalysis12

Catalysts7

Ligands7

Highly enantioselective3

Abstract2

Ligand3

Cyclopropanation2

Hydrogenations2

Catalyst15

Organocatalysis5

Chemistry4

Mechanism3

Alkenes1

Prochiral2

Imines1

Enantioselectivity1

Substrates1

Ketones3

Hydrogenation2

Intermediates2

Methodology1

Reagents1

Additions1

Allylation1

Esters1

Complexes6

Cascade1

Aliphatic1

Heck Reaction3

Intermolecular1

Substituent1

Processes1

Dirhodium1

Aromatic1

Bonds2

Optimization1

Elucidate2

Cycloaddition2

Cleavage under mild2

Reduction1

Molecules3

Synthetic3

Synthesis and Reactions1

Carbonyl1

Complex2

Recent advances1

Situ1

Mild reaction conditions1

Transformations1

Methods3

Model reaction1