Asymmetric addition of 3-substituted benzofuran-2-ones to isatin N-Boc ketimines catalyzed by chiral biscinchona alkaloid catalyst

Zhu, Yi; Zhang, Enge; Luo, Chao; Li, Xin; Cheng, Jiang

doi:10.1016/j.tet.2015.04.114

Cited by 26 publications

(4 citation statements)

References 81 publications

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“…Very recently, isatin-derived ketimines have risen to prominence owing to their versatile electrophilic reactivity, leading to a wide variety of enantioenriched 3-amino quaternary oxindole products. , In this context, noteworthy is that elegant contributions from the groups of Feng, Shao, Wennemers, and others − realized the assembly of vicinal tetrasubstituted stereogenic structures. Despite the elegance of these reports, in general, the simultaneous formation of both stereocenters in a single-step reaction with a tertiary carbon nucleophile through the orchestration of a chiral promoter restricts the variability of the substituents attached to the quaternary carbon center outside the oxindole ring (Scheme ).…”

mentioning

confidence: 99%

An Organocatalytic Asymmetric Friedel–Crafts Addition/Fluorination Sequence: Construction of Oxindole–Pyrazolone Conjugates Bearing Vicinal Tetrasubstituted Stereocenters

et al. 2015

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A highly efficient and practical one-pot sequential process, consisting of an organocatalytic enantioselective Friedel-Crafts-type addition of 4-nonsubstituted pyrazolones to isatin-derived N-Boc ketimines and a subsequent diastereoselective fluorination of the pyrazolone moiety, is developed. This reaction sequence delivers novel oxindole-pyrazolone adducts featuring vicinal tetrasubstituted stereocenters with a 0.5 mol % catalyst loading in high yield with excellent enantio- and diastereocontrol. Notably, chloro, bromo, and thioether functionalities can be readily incorporated, rendering a broad diversity of the product.

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confidence: 99%

An Organocatalytic Asymmetric Friedel–Crafts Addition/Fluorination Sequence: Construction of Oxindole–Pyrazolone Conjugates Bearing Vicinal Tetrasubstituted Stereocenters

et al. 2015

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“…The nucleophilic adducts were produced in excellent yields (up to 99 %), high des (up to>95 : 5 dr ) and high ees (up to 98 %) (Scheme 18). [60] Under the optimized reaction conditions, the reaction of diverse 3‐alkyl substituted benzofuran‐2(3 H )‐ones 73 and 42 a were examined. 3‐Methyl substituted benzofuran‐2(3 H )‐one afforded the corresponding product 75 b with high yields.…”

Section: Organocatalyzed Asymmetric Mannich Reactionmentioning

confidence: 99%

“…Worthy to mention that the biscinchona alkaloid catalyst could generate a chiral pocket which was promising to firmly fix of both the enolated benzofuran‐2‐one and isatin N ‐Boc ketimine, leading to highly effective stereocontrol in the nucleophilic addition reaction. The probable existence of the π‐π effect in substrate and catalyst, possibly contribute to the stereocontrol [60] …”

Section: Organocatalyzed Asymmetric Mannich Reactionmentioning

confidence: 99%

Organocatalyzed Asymmetric Mannich Reaction: An Update

et al. 2021

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The Mannich reaction is a multicomponent reaction resulting in aminoalkylation of an acidic proton placed next to a carbonyl functional group. It involves an appropriate carbonyl compound, such as formaldehyde and a primary or secondary amine or ammonia. The final product is a β‐amino‐carbonyl compound known as a Mannich base. Reactions between aldimines and α‐methylene carbonyls are also considered as Mannich reaction since these imines are generated from the reaction of amines and aldehydes. It comprises the reaction of primary or secondary amines or ammonia, formaldehyde and appropriate α‐CH‐acidic compounds (nucleophiles) such as carbonyl compounds having α‐CH‐acidic, nitriles, acetylenes, aliphatic nitro compounds, α‐alkyl‐pyridines or imines. Owing to the development of asymmetric organocatalysis, reports on asymmetric Mannich reaction have been drastically increased. The asymmetric Mannich reaction offers access to enantioenriched β‐amino ketones or β‐amino aldehydes, which are present as a scaffold in several natural products. Organocatalysts have been developed not only as a supplement to metal‐catalyzed reactions or to biocatalysis, but nowadays, they are extensively used for the synthesis of various optically pure compounds that could not be achieved via metal‐ or biocatalyzed reactions. In this review, we try to update the advances in organocatalyzed asymmetric Mannich reactions, covering the recent advances of the subject from 2008 to date.

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“…In these two reports, the Mannich reaction receptors were aldimines. In recent years, the asymmetric reaction of isatin-derived ketimines has attracted people’s attention . An organocatalytic, stereoselective Mannich reaction of α-fluoroindanones with isatin-derived ketimines is unprecedented.…”

Section: Introductionmentioning

confidence: 99%

Asymmetric Mannich Reaction of Isatin-Derived Ketimines with α-Fluoroindanones Catalyzed by a Chiral Phase-Transfer Catalyst

Zhao,

Wei

et al. 2024

J. Org. Chem.

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A highly enantioselective Mannich reaction of α-fluoroindanones with isatin-derived N-Boc-ketimines catalyzed by a quinine-derived phase-transfer catalyst was developed. A variety of 3-substituted 3-amino-2-oxindoles bearing fluorine-containing, vicinal, tetrasubstituted stereocenters were constructed using this protocol in high yields (83−95%), with moderate to excellent enantioselectivities (66−91%) and high diastereoselectivities (up to >99:1).

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Asymmetric addition of 3-substituted benzofuran-2-ones to isatin N-Boc ketimines catalyzed by chiral biscinchona alkaloid catalyst

Cited by 26 publications

References 81 publications

An Organocatalytic Asymmetric Friedel–Crafts Addition/Fluorination Sequence: Construction of Oxindole–Pyrazolone Conjugates Bearing Vicinal Tetrasubstituted Stereocenters

An Organocatalytic Asymmetric Friedel–Crafts Addition/Fluorination Sequence: Construction of Oxindole–Pyrazolone Conjugates Bearing Vicinal Tetrasubstituted Stereocenters

Organocatalyzed Asymmetric Mannich Reaction: An Update

Asymmetric Mannich Reaction of Isatin-Derived Ketimines with α-Fluoroindanones Catalyzed by a Chiral Phase-Transfer Catalyst

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