Review on Asymmetric Transformations with Chiral Phase-Transfer Catalysts DOI Open Access

Tesfaye Tebeka,

Atitegebe Abera

international research journal of science and technology, Год журнала: 2019, Номер unknown, С. 6 - 12

Опубликована: Дек. 1, 2019

This review focuses onasymmetric transformations with Chiral Phase-Transfer Catalysts and its application. Phase-transfer catalysis is practical methodology for organic synthesis. It possible to achieve highly enantio selective under phase-transfer conditions a variety of ─C─C─ ─C─O─ ─C─N─ bond-forming reactions. The asymmetric using modified cinchona alkaloids, chiral spiro ammonium salts crown ether are among the primary source effective catalyst, which allows access enantiomerically pure unnatural amino acids synthetically useful adducts containing quaternary stereogenic centers. advantage this method simple experimental procedure, large pool, mild reaction condition, inexpensive, environmentally benign reagent use inexpensive reactants. Nowadays, it appears be most important synthetic used in various fields chemistry, also found widespread industrial applications. summarizes synthesis application, transformation some selected reaction, biological activities catalytic especial emphasis given organo catalysis. In obtain products high enriched form by steric hindrance approach method. molecules as catalysts complements traditional organo-metallic approaches

Язык: Английский

Lewis base phase transfer catalyst promoted solvent‐free nucleophilic reactions in ionic liquids: Quantum chemical analysis for cooperative enhancement in SN2 reaction rates DOI Open Access
Young‐Ho Oh, Sungyul Lee

Bulletin of the Korean Chemical Society, Год журнала: 2025, Номер unknown

Опубликована: Янв. 16, 2025

Abstract We present quantum chemical analysis of Lewis base phase transfer catalyst (PTC) facilitated solvent‐free nucleophilic reactions in green solvent/catalyst ionic liquids (ILs). adopt two processes: First, we examine whether and how the reaction rate 18‐crown‐6‐promoted S N 2 is further enhanced by IL [Bmim]OMs. Second, promotion cynation IL‐integrated aza‐crown ether, third, fluorination [2.2.2]‐cryptand IL. Interactions between IL, PTC substrates are shown to give rise lower Gibbs free energies activation, with anion (OMs − ) acting as an additional promoter on counter‐cation M + , (M = K, Cs), thereby mitigating latter's disadvantageous influence nucleophile. thus propose that ILs may be used facilitate processes solvent/ organocatalysts instead environmentally malicious organometallic compounds.

Язык: Английский

Процитировано

0
Recent advances in organocatalytic enantioselective syntheses of β-fluoroamine compounds DOI
Taeyang Do, Geun Ho Kim, Ramón Rios

и другие.

Molecular Catalysis, Год журнала: 2025, Номер 576, С. 114944 - 114944

Опубликована: Фев. 26, 2025

Язык: Английский

Процитировано

0
Phase-transfer-catalyst enabled enantioselective C–N coupling to access chiral boron-stereogenic BODIPYs DOI Creative Commons

Xueqing Zhang,

Xiaojuan Lv,

Luying Guo

и другие.

Nature Communications, Год журнала: 2025, Номер 16(1)

Опубликована: Март 19, 2025

Tetracoordinate boron-based fluorescent materials have shown extensively applications in chemistry, biology and science owing to their unique optoelectronic properties. However, constructing chiral boron-stereogenic fluorophores through practical universal strategies remains rare challenging. Herein, as a proof of concept, we report an enantioselective postfunctionalization boron dipyrromethene dyes (BODIPYs), acess BODIPYs moderate good yields with commendable enantioselectivity. Chiral attracted increasing attention not only distinctively photophysical properties circularly polarized luminescence (CPL) materials, but also diversely structural modification. In this·work, present phase-transfer-catalyst enabled C–N coupling reaction diverse nucleophiles. This method serves SNAr (nucleophilic aromatic substitution reaction) route achieve series amido/amino well demonstrates promising CD and·CPL·activities, excellent biocompatibility, high specificities, showing potential imaging agents. Constructing Here, the authors

Язык: Английский

Процитировано

0
From Cortisone to Enlicitide: A Journey of Synthetic Chemistry Innovations at Merck DOI Creative Commons
Louis‐Charles Campeau

The Journal of Organic Chemistry, Год журнала: 2025, Номер unknown

Опубликована: Апрель 1, 2025

Necessity is the mother of invention. Most synthetic chemistry innovations are driven by our desire to make molecules. In first half 20th century, much this work was inspired natural products, but as we started understand impact that specific molecules could have on biology and human health, a new stimulus for invention appeared. The pharmaceutical industry brought mass production formulation products medicinal purposes quickly tinkering with molecular structure modify compounds' properties, eventually designing from scratch. This necessity improve health manufacture them large scale an excellent innovations. Perspective, examples Merck's groups used highlight types can arise these endeavors.

Язык: Английский

Процитировано

0
Organocatalyzed Enantioselective C–N Bond-Forming SNAr Reactions for Synthesizing Stereogenic-at-Boron BODIPYs DOI Creative Commons
Yonggang Meng, Fang Wei, Z. Y. Pei

и другие.

JACS Au, Год журнала: 2025, Номер unknown

Опубликована: Апрель 2, 2025

Язык: Английский

Процитировано

0
Integrating Achiral Brønsted Base and Chiral Bisguanidinium for Enantioselective Phospha-Michael Addition to Chalcones DOI

Zhenghao Wan,

Hongjie Cao,

Chao Wang

и другие.

ACS Catalysis, Год журнала: 2025, Номер unknown, С. 6426 - 6433

Опубликована: Апрель 4, 2025

Язык: Английский

Процитировано

0
Deracemization of C(sp3)–H Arylated Carbonyl Compounds via Asymmetric Ion-Pairing Photoredox Catalysis DOI

Chenxi Wen,

Zhengke Huang,

Sheng-Ye Zhang

и другие.

Journal of the American Chemical Society, Год журнала: 2025, Номер unknown

Опубликована: Апрель 17, 2025

Deracemization of C(sp3)-H arylated carbonyl compounds faces limitations in terms substrate scope. Through the photoactivation aryl group and stereocontrol generated arene radical cation via asymmetric ion-pairing catalysis, we are able to achieve deracemization at both enolizable unenolizable stereocenters. A diverse range α-, β-, γ-aryl ketones esters, including natural products medicinal derivatives, can be effectively converted into their enantiomers with high enantioselectivity. Mechanistic investigations through combined experimental computational studies suggest that reaction involves single-electron oxidation electron-rich groups, followed by a kinetic resolution resulting intermediates chiral phosphate anion. Deprotonation is identified as stereodetermining step, while stereoselective back electron transfer triplet-state quenching 3 Mes-Acr1+* may also affect enantioselectivity photostationary state.

Язык: Английский

Процитировано

0
Effects of Hydrogen Bonding Solvation by Diverse Fluorinated Bulky Alcohols on the Reaction Rate and Selectivity in Crown Ether Mediated Nucleophilic Fluorination in an Aprotic Solvent DOI Creative Commons
Eloah P. Ávila, Mauro V. de Almeida, Marcelo Siqueira Valle

и другие.

ACS Organic & Inorganic Au, Год журнала: 2024, Номер 5(1), С. 69 - 83

Опубликована: Ноя. 28, 2024

Solvent effects play a critical role in ionic chemical reactions and have been research topic for long time. The solvent molecules the first solvation shell of solute are most important solvating species. Consequently, manipulation structure this can be used to control reactivity selectivity reactions. In work, we report extensive experimental insightful computational studies adding diverse fluorinated bulky alcohols with different abilities fluorination reaction alkyl bromides potassium fluoride promoted by 18-crown-6. We found that stoichiometric amount these acetonitrile solution has an effect on kinetics selectivity. effective alcohol was 2-trifluoromethyl-2-propanol (TBOH-F3), use 3 equiv fluorinate primary bromide led 78% yield just 6 h time at mild temperature 82 °C, 8% E2 yield. more challenging secondary substrate obtained 44% 56% 18 More six or fluorine atoms resulted relatively acidic alcohols, leading large amounts corresponding ethers as side products. widely hexafluoroisopropanol (HFIP) least one monofluorination, indicating both acidity bulkiness features promoting using KF salt. Nevertheless, ether HFIP easily formed substrate, generating highly product. Theoretical calculations predict ΔG ‡ close agreement experiments explain higher induced relation crown alone.

Язык: Английский

Процитировано

1
Enantioselective Synthesis of Chiral Acyclic Nitriles Containing α-All-Carbon Quaternary Stereocenters via Synergistic Palladium and Phase-Transfer Catalysis DOI
Cheng Guo, Yunpeng Dong, Yi Wang

и другие.

ACS Catalysis, Год журнала: 2024, Номер 14(24), С. 18841 - 18850

Опубликована: Дек. 11, 2024

Herein, we present a practical strategy for the asymmetric synthesis of chiral acyclic nitriles featuring α-all-carbon quaternary stereocenters, utilizing synergistic palladium and phase-transfer catalysis from allyl 2-cyanoacetates under mild conditions. This approach offers an efficient reliable method in situ generation tertiary α-cyano carbanions through intramolecular palladium-catalyzed decarboxylative allylic alkylation. Additionally, it enables highly enantioselective control simple via ion-pairing interactions with catalysts. The synthetic utility this is further demonstrated by its scalability to gram-scale subsequent transformation into variety functionalized compounds containing all-carbon stereocenters.

Язык: Английский

Процитировано

0
Review on Asymmetric Transformations with Chiral Phase-Transfer Catalysts DOI Open Access

Tesfaye Tebeka,

Atitegebe Abera

international research journal of science and technology, Год журнала: 2019, Номер unknown, С. 6 - 12

Опубликована: Дек. 1, 2019

This review focuses onasymmetric transformations with Chiral Phase-Transfer Catalysts and its application. Phase-transfer catalysis is practical methodology for organic synthesis. It possible to achieve highly enantio selective under phase-transfer conditions a variety of ─C─C─ ─C─O─ ─C─N─ bond-forming reactions. The asymmetric using modified cinchona alkaloids, chiral spiro ammonium salts crown ether are among the primary source effective catalyst, which allows access enantiomerically pure unnatural amino acids synthetically useful adducts containing quaternary stereogenic centers. advantage this method simple experimental procedure, large pool, mild reaction condition, inexpensive, environmentally benign reagent use inexpensive reactants. Nowadays, it appears be most important synthetic used in various fields chemistry, also found widespread industrial applications. summarizes synthesis application, transformation some selected reaction, biological activities catalytic especial emphasis given organo catalysis. In obtain products high enriched form by steric hindrance approach method. molecules as catalysts complements traditional organo-metallic approaches

Язык: Английский

Процитировано

0