Stereoretentive regio‐ und enantioselektive Allylierung von Isoxazolinonen per planar chiralem Palladacyclus‐Katalysator DOI
Xin Yu,

Lingfei Hu,

Wolfgang Frey

et al.

Angewandte Chemie, Journal Year: 2022, Volume and Issue: 134(42)

Published: July 28, 2022

Abstract Die katalytische allylische Substitution ist eines der wichtigsten Werkzeuge in asymmetrischen Synthese zur enantioselektiven Bildung von C‐C‐Bindungen. Während vorigen Arbeiten eine hohe Effizienz Bezug auf Enantio‐ und Regiokontrolle unter Verwendung verschiedener Katalysatortypen erreicht wurde, besteht starke allgemeine Einschränkung einer sehr ausgeprägten Präferenz für die allylischen Substitutionsprodukten mit ( E )‐konfigurierten C=C‐Doppelbindungen. Hier berichten wir, dass einem planar‐chiralen Palladacyclus‐Katalysator Isoxazolinonen Allylimidaten als Substrate ein diastereospezifisches Reaktionsergebnis erzielt wird, wodurch C=C‐Doppelbindungsgeometrie Allylsubstrate den hoch enantiomerenangereicherten Produkten beibehalten wird. DFT‐Rechnungen zeigen, Reaktionen über einen S N 2‐Mechanismus nicht π‐Allyl‐Pd‐Komplexe ablaufen. Entscheidend Kontrolle Stabilisierung des Fragments im 2‐Übergangszustand durch π‐Wechselwirkungen Phenylsubstituenten Pentaphenylferrocen‐Katalysatorkerns.

Nickel-Catalyzed Aminofluoroalkylative Cyclization of Styrenes with Ethyl Fluoroacetate and Anilines toward Fluoro-γ-Lactams DOI
Fengxiang Zhu, Ziyan Li, Xiao‐Feng Wu

et al.

Organic Letters, Journal Year: 2023, Volume and Issue: 25(47), P. 8535 - 8539

Published: Nov. 20, 2023

A novel method for the nickel-catalyzed multicomponent aminofluoroalkylation/cyclization of styrenes with ethyl fluoroacetate and anilines has been developed. This protocol provides general efficient access to a diverse range fluoro-γ-lactams from simple readily available starting materials. Control experiments prove involvement radical intermediates excluded presence 2-fluoro-N-phenylacetamide.

Language: Английский

Citations

8
Arylideneisoxazole-5(4H)-One Synthesis by Organocatalytic Three-Component Hetero-Cyclization DOI

Ziba Daroughehzadeh,

Hamzeh Kiyani

Polycyclic aromatic compounds, Journal Year: 2023, Volume and Issue: 44(5), P. 3200 - 3221

Published: July 5, 2023

An expedient, green, practical, and vastly efficient three-component cyclo-condensation is catalyzed by triphenylphosphine. The 4-arylideneisoxazol-5(4H)-one heterocycles are generated in good to excellent isolated reaction yields. Experiments show that the best results were obtained using 15 mol% of catalyst under aqueous conditions at room temperature. sonochemical synthesis derivatives also performed 10 triphenylphosphine water as an eco-friendly medium. In comparative method, ultrasonication showed shorter times requires smaller amounts catalyst. While aryl/heteroaryl aldehydes used, variation β-keto-ester was explored. β-keto-esters (ethyl acetoacetate/ethyl 4-chloro-3-oxobutanoate/ethyl 3-oxohexanoate) optimized reacted well afforded corresponding 4-arylideneisoxazol-5(4H)-ones times. approach simple, approximately compatible with pot-, atom-, step-economy.

Language: Английский

Citations

7
Advances in Transition Metal Catalysis and Organocatalysis Approaches towards Asymmetric Synthesis of β-Amino Acid Derivatives DOI

Farrukh Sajjad,

Shuyue Zhang, Ming‐Hua Xu

et al.

Synthesis, Journal Year: 2024, Volume and Issue: unknown

Published: Aug. 16, 2024

Abstract The stereoselective synthesis of β-amino acids has attracted major attention among the synthetic community in recent years. This review provides an overview important advances chiral acid over past decade. It covers development enantioselective methods using transition-metal complexes or organocatalysts, mainly including catalytic asymmetric hydrogenation, Mannich reaction, multicomponent reactions diazo compounds, and conjugate addition. Additionally, optically active by other approaches are also summarized. 1 Introduction 2 Strategies towards Asymmetric Synthesis β-Amino Acids 2.1 Hydrogenation 2.2 Reaction 2.3 Conjugate Addition 2.4 Multicomponent Reactions 2.5 Miscellaneous 2.5.1 from Chiral Amines 2.5.2 Isoxazolidinones 2.5.3 Other Methodologies 3 Summary Outlook

Language: Английский

Citations

2
Efficient Synthesis of 4-Arylmethylene-3-methylisoxazol-5(4H)-one Derivatives Catalyzed by Malic Acid DOI
Hamzeh Kiyani,

Sayed Zakaria Tahmasabi,

Heshmat Allah Samimi

et al.

Letters in Organic Chemistry, Journal Year: 2022, Volume and Issue: 20(2), P. 167 - 174

Published: Sept. 3, 2022

Abstract: The efficient, straightforward, and green procedure was established in the direction of synthesis 4-arylmethylene-3-methylisoxazol-5(4H)-one derivatives using malic acid, which acted as catalyst for three-component heterocyclization reaction. In this reaction, aryl/heteroaryl aldehydes, hydroxylamine hydrochloride, ethyl acetoacetate/ethyl benzoylacetate were applied reactants. reaction optimized to attain best conditions target heterocyclic compounds a single step route. results obtained from optimization experiments 10 mol% acid catalyst, water solvent, 50ºC temperature. noticeable features process are simplicity experimental procedure, easy separation pure product mixture, operation, avoidance any hazardous organic solvents, no use chromatographic purification techniques, clean profiles, high yields, relatively short time, eco-friendliness

Language: Английский

Citations

10
Catalytic Asymmetric Chlorination of Isoxazolinones DOI

Nick Wannenmacher,

Noah Keim,

Wolfgang Frey

et al.

European Journal of Organic Chemistry, Journal Year: 2022, Volume and Issue: 2022(9)

Published: Feb. 14, 2022

Abstract Organic compounds featuring a chlorine substituted stereocenter are frequently found in nature and interesting for pharmaceutical applications as synthetic building blocks. Catalytic methods to generate such stereocenters by C,H bond functionalization still relatively rare. Here we report the first catalytic asymmetric chlorination of isoxazolinones, synthetically biologically class heterocycles, which can be considered precursors β‐aminoacids. The title reaction was catalyzed with high enantioselectivity planar chiral ferrocene based palladacycle excellent yields. It is showcased that products valuable post‐synthetic transformations. An S N 2 proceeded smooth inversion absolute configuration. substitution product could then transformed into an α‐azido β‐aminoacid derivative via reductive, diastereoselective ring opening.

Language: Английский

Citations

8
Strategies for the Enantioselective Synthesis of 2‐Isoxazolines and 2‐Isoxazolin‐5‐ones Bearing Fully Substituted Stereocenters** DOI Creative Commons
Gillian McArthur, Steven-Alan G. Abel, Giulio Volpin

et al.

European Journal of Organic Chemistry, Journal Year: 2022, Volume and Issue: 2022(45)

Published: Dec. 1, 2022

Abstract Although there is an abundance of methods for the enantioselective synthesis 2‐isoxazolines and 2‐isoxazolin‐5‐ones, relatively few these approaches have been reported when heterocycles bear fully substituted stereocenters. In this review, we will detail that used to successfully accomplish challenging asymmetric transformations give insights into their importance, such as allowing access unique three‐dimensional chemical space. The limitations currently known reactions be discussed, well highlighting future developments needed advance research field.

Language: Английский

Citations

8
Stereoretentive Regio‐ and Enantioselective Allylation of Isoxazolinones by a Planar Chiral Palladacycle Catalyst DOI Creative Commons
Xin Yu,

Lingfei Hu,

Wolfgang Frey

et al.

Angewandte Chemie International Edition, Journal Year: 2022, Volume and Issue: 61(42)

Published: July 28, 2022

The catalytic allylic substitution is one of the most important tools in asymmetric synthesis to form C-C bonds an enantioselective way. While high efficiency was previously accomplished terms enantio- and regiocontrol using different catalyst types, a strong general limitation very pronounced preference for formation products with (E)-configured C=C double bonds. Herein, we report that planar chiral palladacycle diastereospecific reaction outcome achieved isoxazolinones imidates as substrates, thus maintaining bond geometry substrates highly enantioenriched products. DFT calculations show reactions proceed via S

Language: Английский

Citations

7
Enantioselective construction of quaternary stereocenters via organocatalytic arylation of isoxazolin-5-ones with o-quinone diimides DOI Creative Commons
Ricardo Torán,

Eduardo Portillo,

Amparo Sanz‐Marco

et al.

Organic Chemistry Frontiers, Journal Year: 2023, Volume and Issue: 10(24), P. 6081 - 6086

Published: Jan. 1, 2023

A bifunctional squaramide catalyzes the enantioselective arylation of isoxazolin-5-ones with o -quinone diimides ( -QDIs) to give featuring an arylated quaternary stereocenter in high yields and excellent enantioselectivities.

Language: Английский

Citations

4
Organocatalytic enantioselective Mannich reaction of isoxazol-5(4H)-ones to isatin-derived ketimines DOI Creative Commons
Ricardo Torán,

Dario Puchán,

Amparo Sanz‐Marco

et al.

Organic & Biomolecular Chemistry, Journal Year: 2022, Volume and Issue: 20(43), P. 8395 - 8399

Published: Jan. 1, 2022

An efficient organocatalytic asymmetric Mannich reaction between isoxazol-5(4 H )-ones and isatin-derived ketimines has been developed.

Language: Английский

Citations

6
A Planar‐Chiral Palladium Complex Derived from a Weak Oxygen Donor N,N‐Diisopropyl Ferrocenecarboxamide Ligand DOI
Raviraj Ananda Thorat, Yogesh Mandhar, Devendra Parganiha

et al.

ChemistrySelect, Journal Year: 2023, Volume and Issue: 8(1)

Published: Jan. 2, 2023

Abstract The reaction of chiral 2‐iodoferrocenecarboxamide, palladium(II) acetate, and triphenylphosphine ligand in acetonitrile has been resulted the formation an air‐stable ( S p )‐2‐( N,N ‐diisopropyl ferrocenecarboxamide) iodide complex. isolated palladium complex was thoroughly characterized by multi‐nuclear 1 H, 13 C, 31 P) NMR, IR spectroscopy, mass spectrometry, polarimetry, CHN analysis, cyclic voltammetry single crystal X‐ray crystallography (XRD). single‐crystal XRD analysis reveals a square planar geometry around atom with strong amide oxygen‐Pd bond [2.095(6) Å]. crystallized C2 ‐chiral space group having Flack parameter value 0.011(14), which is close to 0 indicative enantiomeric purity electrochemical study two‐electron redox couple due ferrocenyl Fe(II) palladacyclic Pd(II) center. In differential pulse (DPV), two peaks were observed at 450 mV 590 vs. Ag/AgCl. Further, synthesized palladacyle also explored Suzuki‐Miyaura coupling as substrate catalyst for Tsuji‐Trost phosphonation reactions.

Language: Английский

Citations

3