Propagative isatin in organic synthesis of spirooxindoles through catalysis

Tetrahedron, Journal Year: 2023, Volume and Issue: 134, P. 133308 - 133308

Published: Feb. 14, 2023

Language: Английский

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Cu-Catalyzed Asymmetric 1,3-Dipolar Cycloaddition of N-2,2,2-Trifluoroethylisatin Ketimines Enables the Desymmetrization of N-Arylmaleimides: Access to Enantioenriched F₃C-Containing Octahydropyrrolo[3,4-c]pyrroles

Organic Letters, Journal Year: 2022, Volume and Issue: 24(22), P. 4052 - 4057

Published: May 27, 2022

With a Cu(OTf)2/chiral ferrocenyl P,N-ligand complex as catalyst, the enantioselective desymmetrization of N-arylmaleimides was successfully realized by taking advantage asymmetric 1,3-dipolar cycloaddition reaction N-2,2,2-trifluoroethylisatin ketimines. A series structurally diverse F3C-containing octahydropyrrolo[3,4-c]pyrroles, bearing four contiguous carbon stereocenters and one stereogenic chiral C-N axial bond, were obtained with excellent results (≤99% yield, >20:1 dr, 99% ee).

Language: Английский

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Stereoselective synthesis of CF₃-containing spirocyclic-oxindoles using N-2,2,2-trifluoroethylisatin ketimines: an update

RSC Advances, Journal Year: 2023, Volume and Issue: 13(11), P. 7063 - 7075

Published: Jan. 1, 2023

Recent updates on the synthesis of CF 3 -containing spirocyclic-oxindoles by employing N -2,2,2-trifluoroethylisatin ketimines are described in this review article.

Language: Английский

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Recent Advances of N-2,2,2-Trifluoroethylisatin Ketimines in Organic Synthesis

Molecules, Journal Year: 2023, Volume and Issue: 28(7), P. 2990 - 2990

Published: March 27, 2023

The special properties of fluorine atoms and fluorine-containing groups have led to an increasing number applications for organic compounds, which are also extremely widely used in the field new drug development. Unfortunately, naturally fluorinated organics rare nature, so selective introduction or into molecules is very important pharmaceutical/synthetic chemists. N-2,2,2-trifluoroethylisatin ketimines received attention many chemists since they were first developed as synthons 2015. This paper reviews synthesis reactions trifluoroethyl isatin ketimine has been involved recent years, focusing on types stereoselectivity products, provides a prospect its application this field.

Language: Английский

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Chiral Brønsted Base Activation of Donor–Acceptor Cyclopropanes toward Diastereo- and Enantioselective [3 + 2] Cycloaddition with Isatin-Derived Ketimines

The Journal of Organic Chemistry, Journal Year: 2024, Volume and Issue: 89(12), P. 8691 - 8705

Published: June 10, 2024

Organocatalyzed diastereo- and enantioselective [3 + 2] cycloaddition reactions of donor-acceptor (D-A) cyclopropanes with isatin-derived ketimines are presented. Different from well-developed Lewis acid activation protocols which promote the reactivity D-A through coordinating to acceptor group, in this reaction, dicyanocyclopropylmethyl ketones can be activated nucleophilic donor group by using dihydroquinine-derived squaramide as Brønsted base catalyst. The reaction affords functionalized spiro[oxindole-3,2'-pyrrolidines] two nonadjacent tetra- tri-substituted stereocenters 83-99% yields, moderate excellent diastereoselectivities (up >20:1 diastereomeric ratio (dr)), enantioselectivities >99% enantiomeric excess (ee)) under mild conditions.

Language: Английский

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1,3‐Dipolar Cycloaddition of 3‐Chromonyl‐Substituted Glycine Imino Esters with Arylidenes and in situ Diastereodivergent via Retrocycloaddition

Chemistry - An Asian Journal, Journal Year: 2023, Volume and Issue: 18(10)

Published: April 3, 2023

1,3-Dipolar cycloaddition through in situ generation of azomethine ylide provides a straightforward and critically important sustainable approach for access to diverse pyrrolidine chemical space. Herein, we developed metal-free AcOH-activated 1,3-dipolar protocol that permits the synthesis uncommon cycloadducts with excellent diastereoselectivity. The challenging substrates 3-formylchromone, glycine ester.HCl arylidene dipolarophile were reacted presence AcONa, which played dual role as base AcOH source, deliver firstly endo-cycloadduct. Under prolonged reaction time at room temperature or heating; endo-adduct underwent diastereodivergent via sequence retro-cycloaddition, stereomutation generated syn-dipole into anti-dipole recycloaddition; furnish scarcely known exo'-cycloadduct high diastereodivergency. worked well broad range stereochemistry obtained was determined without ambiguity using NMR- X-ray analysis. Experimental theoretical DFT calculation studies performed support proposed mechanism elucidate key process seems more beneficial than other transition metal-catalyzed processes.

Language: Английский

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Diastereoselective Synthesis of Spiro[benzopyrrolothiazole-thioazlactone] Derivatives from Erlenmeyer Thioazlactones and Azomethine Ylides

Synthesis, Journal Year: 2022, Volume and Issue: 54(20), P. 4615 - 4621

Published: July 8, 2022

Abstract Erlenmeyer thioazlactones reacted with 3-(2-oxo-2-arylethyl)benzo[d]thiazol-3-ium bromides in the presence of Et3N MeCN to afford 1-aryloyl-2′-(benzylthio)-2-aryl-2,3a-dihydro-1H,5′H-spiro[benzo[d]pyrrolo[2,1-b]thiazole-3,4′-thiazol]-5′-ones. Formally, this transformation can be regarded as a Huisgen reaction exocyclic carbon–carbon double bond and azomethine ylides generated situ. Evidence for structure product was obtained from single-crystal X-ray analyses. The important feature is fact it forms four stereogenic centers, one which quaternary, excellent selectivity.

Language: Английский

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Recent Progress on the [3+2] Cycloaddition Route for the Synthesis of All-Carbon Quaternary Stereocentres

SynOpen, Journal Year: 2022, Volume and Issue: 06(04), P. 270 - 285

Published: Sept. 20, 2022

Abstract Construction of all-carbon quaternary centres is an important task in organic synthesis. In spite the challenges associated with Csp3–Csp3 bond construction a sterically constrained environment, significant advances have been made this area. Among latter, both catalytic and noncatalytic [3+2] cycloaddition approaches gained wide attention recently. This short review summarizes reactions reported during period 2016–2022 for synthesis molecules possessing one or more stereocentres.

Language: Английский

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Rapid Access to Free Phenols by Photocatalytic Acceptorless Dehydrogenation of Cyclohexanones at Room Temperature

Published: April 10, 2023

Phenols are ubiquitous substructures in natural products and bioactive compounds. However, practical methods for the direct construction of phenols under mild conditions remains challenging. Herein, a photocatalytic acceptorless dehydrogenative aromatization cyclohexanones or cyclohexenones at room temperature has been developed. The reaction features visible-light cobalt co-catalyzed sequential dehydrogenation in-situ formed enol silyl ethers, which regarded as challenging process. This operationally simple method enables series with diverse substitution patterns from cyclohexenones, providing general straightforward synthesis starting materials conditions.

Language: Английский

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Chiral-Boron Complex-Catalyzed Asymmetric [3 + 2] Cycloaddition of 2′-Hydroxychalcones with N-2,2,2-Trifluoroethylisatin Ketimines

The Journal of Organic Chemistry, Journal Year: 2024, Volume and Issue: 89(16), P. 11607 - 11619

Published: Aug. 1, 2024

A highly efficient asymmetric [3 + 2] cycloaddition reaction of 2'-hydroxychalcones with

Language: Английский

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