Organocatalytic Asymmetric Synthesis of Bridged <i>O</i>,<i>O</i>‐Ketals with Spirooxindole Motif

Balha, Megha; Soni, Chintan; Pan, Subhas Chandra

doi:10.1002/ejoc.201900120

Cited by 12 publications

(5 citation statements)

References 64 publications

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“…The reaction proceeds through conjugate addition followed by diastereoselective ketalisation of oxindoles 195 and ortho -hydroxy-benzylidene acetones 194 (Scheme 65 ). 120 The spirooxindole products were obtained via catalysis with an epi -cinchonine primary amine, and high yields and high diastereo- and enantioselectivities were obtained. The methodology is of significance given the pharmaceutical importance of spirooxindoles and bridged ketals.…”

Section: Hydrogen-bonding Catalysismentioning

confidence: 99%

Unravelling the Development of Non-Covalent Organocatalysis in India

Sahoo¹,

Panda²,

Sahoo³

2022

Synlett

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This review is devoted to underpinning the contributions of Indian researchers towards asymmetric organocatalysis. More specifically, a comprehensive compilation of reactions mediated by a wide range of non-covalent catalysis is illustrated. A detailed overview of vividly catalogued asymmetric organic transformations promoted by hydrogen bonding and Brønsted acid catalysis, alongside an assortment of catalysts is provided. Although asymmetric organocatalysis has etched itself in history, we aim to showcase the scientific metamorphosis of Indian research from baby steps to large strides within this field. 1 Introduction2 Non-Covalent Catalysis and Its Various Activation Modes3 Hydrogen-Bonding Catalysis3.1 Urea- and Thiourea-Derived Organocatalysts3.1.1 Thiourea-Derived Organocatalysts3.1.2 Urea-Derived Organocatalysts3.2 Squaramide-Derived Organocatalysts3.2.1 Michael Reactions3.2.2 C-Alkylation Reactions3.2.3 Mannich Reactions3.2.4 [3+2] Cycloaddition Reactions3.3 Cinchona-Alkaloid-Derived Organocatalysts3.3.1 Michael Reactions3.3.2 Aldol Reactions3.3.3 Friedel–Crafts Reactions3.3.4 Vinylogous Alkylation of 4-Methylcoumarins3.3.5 C-Sulfenylation Reactions3.3.6 Peroxyhemiacetalisation of Isochromans3.3.7 Diels–Alder Reactions3.3.8 Cycloaddition Reactions3.3.9 Morita–Baylis–Hilman Reactions4 Brønsted Acid Derived Organocatalysts4.1 Chiral Phosphoric Acid Catalysis4.1.1 Diels–Alder Reactions4.1.2 Addition of Ketimines4.1.3 Annulation of Acyclic Enecarbamates5 Conclusion

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Section: Hydrogen-bonding Catalysismentioning

confidence: 99%

Unravelling the Development of Non-Covalent Organocatalysis in India

Sahoo¹,

Panda²,

Sahoo³

2022

Synlett

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“…Balha and co‐workers described in 2019, a modification for the organocatalytic asymmetric synthesis of a spirooxindole bearing an acetal structure that consisted of changing the ortho ‐hydroxy‐cinnamaldehyde 121 for ortho ‐hydroxybenzylidene acetone 124 . Therefore, N ‐benzyl dioxindole 120 and the ortho ‐hydroxybenzylidene acetone 124 were treated with a catalytic amount of cinchonine derived primary amine (10 mol‐%) 125 as catalyst in the presence of benzoic acid (10 mol‐%) as an additive in THF, as shown in Scheme .…”

Section: Asymmetric Synthesis Of Spirooxindoles In One Stepmentioning

confidence: 99%

“…The reaction mechanism can be rationalized by the formation of a respective imine between ketone 124 and chiral primary amine 125 , promoted by benzoic acid. Subsequently, the imine and the enol tautomer led to the formation of the intermediate II via a Michael addition reaction, followed by an acetalization reaction to deliver the spirooxindole 126 , as shown in Scheme …”

Section: Asymmetric Synthesis Of Spirooxindoles In One Stepmentioning

confidence: 99%

Organocatalytic Synthesis of Chiral Spirooxindoles with Quaternary Stereogenic Centers

Sansinenea

Martínez

2020

Eur J Org Chem

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The structure of spirooxindoles is present in a large number of natural compounds, with relevant and different biological activities. The organic synthesis of these compounds has been a synthetic challenge due to the fusion of two or more cycles with one or more contiguous stereogenic centers. In this review, it has been described, the feasibility of organocatalytic asymmetric synthesis for the achievement of chiral spirooxindoles through two‐ or three‐component reaction in the presence of a chiral organocatalyst producing the compounds with high yield, high diastereoselectivity and with high enantiomeric purity. This review covers literature from 2010 to 2019. The most explored reactions for this purpose have been 1,3‐dipolar cycloaddition, Diels‐Alder and nucleophilic heterocyclic carbenes reactions, where their reaction mechanisms showed in this review are an approach of a possible mechanism.

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“…In most of the cases the reaction temperature for ketal formation step was increased to 50°C to obtain acceptable yields (Scheme 64). [258] The derivatives of 3-amino-2-oxindole can be efficiently used to obtain spirocyclic compounds. In the three-component system of aminoindolone, aldehydes and dipolarophile, the first stage is the condensation of 3-aminooxindole 244 with aryl-, arylvinylaldehydes or methylpropanal 245 to form imines.…”

Section: Development Of Approaches To the Synthesis Of 3-spiro-2-oxinmentioning

confidence: 99%

“…In most of the cases the reaction temperature for ketal formation step was increased to 50 °C to obtain acceptable yields ( Scheme 64). [258] …”

Section: Syntheses Of Spiroheterocycles From 3‐alkylidene‐indol‐2‐onementioning

confidence: 99%

Advances in the Synthesis of Benzo‐Fused Spiro Nitrogen Heterocycles: New Approaches and Modification of Old Strategies

Гатауллин

2020

Helvetica Chimica Acta

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The review covers the results of studies published in the literature on the synthesis of spiro-linked heterocycles of the indole, quinoline, benzoxazine, benzothiazine, indenoquinoxaline, pyridopyrimidine, and acridine series. Possible approaches to the synthesis of spirocycles through a sequence of well-known Knoevenagel, Michael reactions, deamination cyclization of 1,2-dicarbonyl, CH-acid compounds, direct cycloaddition of activated olefins to isatins, 3-alkylideneindoles, 2-oxindoles, in situ generated azomethine ylides, indenoquinoxalines are analyzed. Attention is drawn to approaches to the preparation of spiro-fused compounds using reactions of intra-and intermolecular dearomatization of indoles. Recent advances in the synthesis of spiro-linked benzo heterocycles from derivatives of 2-olefin substituted anilines are summarized. The examples of the synthesis of spiro-fused heterocycles by means of metal complexes catalyzed decomposition of diazo compounds are given. Some syntheses of biologically active representatives are shown, as well as the use of transformations of spiroheterocycles in the preparation of other heterocycles.

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Organocatalytic Asymmetric Synthesis of Bridged O,O‐Ketals with Spirooxindole Motif

Cited by 12 publications

References 64 publications

Unravelling the Development of Non-Covalent Organocatalysis in India

Unravelling the Development of Non-Covalent Organocatalysis in India

Organocatalytic Synthesis of Chiral Spirooxindoles with Quaternary Stereogenic Centers

Advances in the Synthesis of Benzo‐Fused Spiro Nitrogen Heterocycles: New Approaches and Modification of Old Strategies

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