Chiral Lewis acid catalystSynthesisCarboxylicEnantioselectiveCatalysisCatalystReactionCatalystsLigandsReductiveChemistryIntermediatesMethylHydrogenBasesCompoundsEstersSubstrateEnantioselectivityBoronReactionsGenerateDocumentDeionized waterCatalyticAlcoholsDerivativesAminoMicrowave-assistedReactTransitionBaseMultipleReportLeaving groupRecentProductionFormation
Chiral Lewis acid catalyst2
- Good enantioselectivity has been observed when a chiral Lewis acid catalyst is used. (wikipedia.org)
- [2] This work was the forerunner of a vast quantity of present-day research on the binaththol based chiral Lewis acid catalyst. (chem-station.com)
Synthesis3
- Achiral Lewis acids have been used for decades to promote the synthesis of racemic mixtures in myriad different reactions. (wikipedia.org)
- Currently, some emerging processes that were developed for advanced biodiesel production include microwave-assisted synthesis, ultrasonic-assisted synthesis, supercritical transesterification, and liquid phase plasma discharge technology. (undip.ac.id)
- After these pioneering researches in Lewis acid chemistry, Yamamoto has become aware of the vast importance of chiral Lewis acids in modern asymmetric synthesis. (chem-station.com)
Carboxylic1
- Hydrolysis then gives enantiomerically pure carboxylic acid. (chempedia.info)
Enantioselective3
- Since the 1960s, chemists have used Chiral Lewis acids to induce enantioselective reactions. (wikipedia.org)
- Among these approaches, the dipole/HOMO-controlled reactions of electron-deficient alkenes are especially promising because a variety of combinations between chiral Lewis acids and electron-deficient alkenes have been well investigated in the study of catalyzed enantioselective Diels-Alder reactions. (chempedia.info)
- Finally, and perhaps most interestingly, studies aimed at enantioselective catalysis are presented, resulting in the first example of enantioselective Lewis-acid catalysis of an organic transformation in water. (chempedia.info)
Catalysis2
- His current interests are mainly development of new synthetic reactions in the filed of acid catalysis including designer Lewis and Brønsted acids, and combination of these two acid systems targeting more versatile, more selective, and more reactive catalysts, aiming at environmentally benign systems. (chem-station.com)
- It was demonstrated that Lewis-acid catalysis of this reaction can lead to impressive accelerations, particularly in aqueous media . (chempedia.info)
Catalyst4
- Chiral Lewis acids (CLAs) are a type of Lewis acid catalyst. (wikipedia.org)
- Our findings reveal for triarylboranes that potential catalytic dehydrogenation routes comprise of two main events: ion pair formation from NH3BH3 in the presence of a catalyst assisted by a nucleophile and subsequent H2 release from the ion pair. (researcher-app.com)
- Donor solvents and the B−H hydride of NH3BH3 act as a nucleophile to facilitate ion-pair formation from NH3BH3 and the Lewis acid catalyst in donor and nondonor solvents, respectively. (researcher-app.com)
- Our studies reveal that by the careful tuning of the hydride affinity of the Lewis acid catalyst in combination with nondonor solvents, rate-limiting barriers for dehydrogenation can be reduced to approximately 19-20 kcal mol−1, which would enable catalytic turnovers at room temperature. (researcher-app.com)
Reaction4
- Chiral Lewis acids have proven useful in the ene reaction. (wikipedia.org)
- When catalyzed by an achiral Lewis acid, the reaction normally provides good diastereoselectivity. (wikipedia.org)
- As for the oxo- Diels-Alder reaction , not much has been reported other Lewis acids are usually superior [26]. (chempedia.info)
- What is the influence of ligands on the Lewis acid on the rate and selectivity of the Diels-Alder reaction If enantioselectivity can be induced in water, how does it compare to other solvents Chapter 3 deals with these topics. (chempedia.info)
Catalysts3
- The derived predictions could assist the future design of Lewis acid-base systems with desired properties and applicability as metal-free hydrogenation catalysts. (elsevierpure.com)
- In 1985, he first introduced binaphthol as a key ligand for chiral Lewis acid catalysts. (chem-station.com)
- Since then, an extensive set of successful chiral Lewis-acid catalysts has been prepared. (chempedia.info)
Ligands1
- The chiral-altering ligands employed for synthesizing these acids often have multiple Lewis basic sites (often a diol or a dinitrogen structure) that allow the formation of a ring structure involving the metal atom. (wikipedia.org)
Reductive5
- Lewis Acid-Assisted C(sp3)-C(sp3) Reductive Elimination at Gold published in the J. Am. Chem. (dimocat.com)
- The electronic features of this Lewis-assisted reductive elimination at gold have been deciphered by intrinsic bond orbital analyses. (dimocat.com)
- Sufficient Lewis acidity of boron is required for the ambiphilic ligand to trigger the C(sp3)-C(sp3) coupling, as shown by complementary studies with two other phosphine-boranes, and the addition of chlorides slows down the reductive elimination of ethane. (dimocat.com)
- The synthetic approach to protected l-Dap methyl esters uses appropriately masked 2,3-diaminopropanols, which are obtained via reductive amination of an aldehyde prepared from the commercial amino acid Nα-Fmoc-O-tert-butyl-d-serine, used as the starting material. (unical.it)
- Reductive amination is carried out with primary amines and sulfonamides, and the process is assisted by the Lewis acid Ti(OiPr)4. (unical.it)
Chemistry2
- In particular, his research laid the foundation for modern designer Lewis and Brønsted acid chemistry. (chem-station.com)
- He was intrigued by the chemistry of the carbonyl compound-Lewis acid complex and introduced the unusually bulky organoaluminum reagents, methylaluminum bis(2,6-di- tert -butyl-4-methylphenoxide) ( MAD ) and aluminum tris(2,6-diphenylphenoxide) ( ATPH ). (chem-station.com)
Intermediates1
- Ground state diastereomers and enantiomers are of equal energy in the ground state, and when reacted with an achiral Lewis acid, their diastereomeric intermediates, transition states, and products are also of equal energy. (wikipedia.org)
Methyl1
- A synthetic strategy for the preparation of two orthogonally protected methyl esters of the non-proteinogenic amino acid 2,3-l-diaminopropanoic acid (l-Dap) was developed. (unical.it)
Hydrogen3
- We report herein a comprehensive theoretical study of the thermodynamics and kinetics of molecular hydrogen activation by frustrated Lewis pairs (FLPs). (elsevierpure.com)
- Metal-free H 2 activation: Computational studies clarify the reasons for the experimentally observed different abilities of a series of frustrated Lewis pairs (FLPs) to activate molecular hydrogen (see figure). (elsevierpure.com)
- There are other compounds that are corrosive to living tissues and are less obvious (Lewis acids, calcium oxide, concentrated hydrogen peroxide, sodium hypochlorite, acid anhydrides, alkylating agents, some organics, etc. (illinois.edu)
Bases3
- A series of intermolecularly combined boranes (Lewis acids) and phosphines (Lewis bases), with experimentally established different reactivities towards H 2 , have been subjected to DFT and (SCS-)MP2 calculations, and analyzed in terms of their structural properties, the energetics of association of the FLPs, and the kinetics of their interactions with H 2 and hydrogenation to the ion-pair products. (elsevierpure.com)
- Common corrosives include strong acids, strong bases, and concentrated solutions of weak acids or bases. (illinois.edu)
- Some substances may be classified as acids or bases but their actual level of corrosiveness is low when in contact with the body or eyes and would not be considered likely to cause injuries. (illinois.edu)
Compounds1
- The strong Lewis acidity of organoaluminum compounds appears to account for their strong tendency to form a stable 1:1 complex. (chem-station.com)
Esters1
- Chiral esters and amides of acrylic acid are particularly useful because the chiral auxiliary can be easily recovered by hydrolysis of the adduct. (chempedia.info)
Substrate2
- These acids affect the chirality of the substrate as they react with it. (wikipedia.org)
- In short, the reagents make a combined Lewis acid - Lewis base attack on a substrate with less activation energy, a field opened by Yamamoto's early and highly original studies. (chem-station.com)
Enantioselectivity1
- Because of the lower temperature required and the greater stereoselectivity observed in Lewis acid catalyzed reactions , the best enantioselectivity is often observed in the catalyzed reactions . (chempedia.info)
Boron1
- It is well known that mono-boron-based Lewis acids are largely ineffective to facilitate the catalytic dehydrogenation of NH3BH3. (researcher-app.com)
Reactions2
- Bronsted acid-assisted chiral Lewis acid (BLA) catalyzes a number of diene-aldehyde cycloaddition reactions. (wikipedia.org)
- Fluorinated malonic acid half thioesters (F-MAHTs) were used as thioester enolate equivalents in organocatalyzed addition reactions to isatins. (nih.gov)
Generate1
- The Lewis acid moiety first abstracts the chloride to generate a zwitterionic Au(III) complex, which then readily undergoes C(sp3)-C(sp3) coupling. (dimocat.com)
Document1
- This Emergency Eyewash and Shower Program document was developed to assist campus units in understanding the requirements set forth by that policy. (illinois.edu)
Deionized water2
- In a 13-week gavage study, B6C3F1 mice (20 per sex per dose) received MCA (as an acid in deionized water) at doses of 0, 25, 50, 100, 150 or 200 mg/ kg bw per day, 5 days per week. (canada.ca)
- In the same study as above, six groups of F344 rats (20 per sex per dose) received MCA (as an acid in deionized water) by gavage at 0, 30, 60, 90, 120 or 150 mg/ kg bw per day, 5 days per week, for 13 weeks. (canada.ca)
Catalytic4
- Particularly, the allylations of some ketones in water hardly occur in catalytic amount of auxiliary agents such as Lewis acids and mediators [4] . (chemistrymag.org)
- Despite recent achievements in the field of frustrated Lewis pairs (FLPs) for small molecule activations, the reversible activation and catalytic transformations of N-H-activated ammonia remain a challenge. (uni-paderborn.de)
- The resulting highly Lewis acidic boron compounds were used for catalytic C-F and S-F bond activation. (uni-paderborn.de)
- Hydrazones were obtained in 76-78% yield via condensation of (2S,5R)-2-isopropyl-5-methylcyclohexanone with 4-R-phenoxyacetic acid hydrazides in the presence of a catalytic amount of glacial acetic acid. (hacettepe.edu.tr)
Alcohols1
- A Pd/Cu catalyst system facilitates the diboration of unactivated propargylic alcohols with pentafluoroboronic acid and diboron to generate ( Z )-allyl, vinyldiboronates. (rsc.org)
Derivatives2
- The 5-aminosalicylic acid (ASA) derivatives are effective in reducing inflammatory reactions. (medscape.com)
- Herein, we report the photocatalytic decarboxylative alkenylation reactions of N -(acyloxy)phthalimide derived from α-amino and α-hydroxy acids with 1,1-diarylethene, and with cinnamic acid derivatives through double decarboxylation, using NaI and PPh 3 as redox catalysts. (rsc.org)
Amino1
- However, by day 155 the spike protein had acquired a further four amino acid changes, namely S255F, S477N, H655Y and D1620A and a two amino acid deletion (ΔH69/ΔV70). (medrxiv.org)
Microwave-assisted3
- However, there is no report about microwave-assisted allylation of carbonyl compound in water yet. (chemistrymag.org)
- The microwave-assisted oxidation of benzyl alcohol reached 45% conversion after 10 min. (beilstein-journals.org)
- The conversion of the alkylation of toluene in both microwave-assisted and conventional heating methods was higher than 99% after 3 min and 30 min, respectively. (beilstein-journals.org)
React2
- These acids affect the chirality of the substrate as they react with it. (wikipedia.org)
- Most of the title compounds readily react with carbon dioxide to provide stable adducts, although the formation of the Lewis acid/base adducts was observed in the solid state. (uni-paderborn.de)
Transition1
- Ground state diastereomers and enantiomers are of equal energy in the ground state, and when reacted with an achiral Lewis acid, their diastereomeric intermediates, transition states, and products are also of equal energy. (wikipedia.org)
Base4
- On the base of this optimization, different Lewis acids were employed in the allylation respectively. (chemistrymag.org)
- Here we report on a rare combination of an aluminium Lewis acid and a carbon Lewis base. (uni-paderborn.de)
- Although the formation of the Lewis acid/base adduct is observed in the solid state, which at first glance leads to formally quenched FLP reactivity, we show that the title compound readily reacts with non-aqueous ammonia thermoneutrally and splits the N-H bond reversibly at ambient temperature. (uni-paderborn.de)
- Acid and base catalysts have been successfully synthesized, characterized, and applied. (researchgate.net)
Multiple1
- Example applications of multiple methods to the degradation of cellulose and tartaric acid. (cardiff.ac.uk)
Report1
- We report on so-called "hidden FLPs" (FLP: frustrated Lewis pair) consisting of a phosphorus ylide featuring a group 13 fragment in the ortho position of a phenyl ring scaffold to form five-membered ring structures. (uni-paderborn.de)
Leaving group1
- Picolinate as a chelation-assisted leaving group could be activated by Cu(OTf) 2 and avoided the use of harsh Lewis acids. (nih.gov)
Recent1
- In recent years, it has been reported that these reactions can also be promoted by Lewis acids [ 9 - 20 ]. (hindawi.com)
Production2
- The production of ammonia and consequent buffering of the acid environment of the human stomach are essential for H. pylori pathogenesis. (medscape.com)
- Metabolites of the drug may decrease inflammation by blocking the production of arachidonic acid metabolites in colonic mucosa. (medscape.com)
Formation1
- The Lewis acid (BF3-Et2O) and Ac2O assisted fragmentation of 3β-acetoxy-5,19-cyclo-pregna-6,20-dione leads to the formation of a B-homo-steroid (3ß,7-Diacetoxy-B-homo-pregna-5(10),6-dien-2-one). (hut-verlag.de)