Organocatalytic Asymmetric Reaction between α‐Cyano Enones and Dioxindoles: Synthesis of Dihydrofuran‐Spirooxindoles

Biswas, Subhankar; Balha, Megha; Das, Suman; Pan, Subhas Chandra

doi:10.1002/ajoc.202200359

Cited by 2 publications

(1 citation statement)

References 49 publications

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“…3a reacted with Boc 2 O to give the N , N , N -triBoc-protected product 7 in 71% yield. The diazotization and hydrolysis of the amino group of 3′b could generate the enol 8 in 25% yield under NaNO 2 / p -TsOH [ 47 ]. Finally, 5a can be converted into N -acetyl product 9 with a high yield (86%).…”

Section: Resultsmentioning

confidence: 99%

K2CO3-Promoted Formal [3+3]-Cycloaddition of N-Unsubstituted Isatin N,N′-Cyclic Azomethine Imine 1,3-Dipoles with Knoevenagel Adducts

Yang

Li²,

Wang

et al. 2023

Molecules

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The synthesis of dicyclic spiropyridazine oxoindole derivatives by using [3+3]-cycloaddition of N-unsubstituted isatin N,N’-cyclic azomethine imine 1,3-dipoles was reported. The products bearing two consecutive stereocenters, including spiroquaternary stereocenters in one ring structure, can be effectively obtained in moderate to excellent yields (20–93%) and low to moderate diastereoselectivities (1:9–10:1 dr). The synthesized compounds (>35 examples) were characterized by single-crystal XRD, FTIR, NMR, and mass spectral analysis.

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Section: Resultsmentioning

confidence: 99%

K2CO3-Promoted Formal [3+3]-Cycloaddition of N-Unsubstituted Isatin N,N′-Cyclic Azomethine Imine 1,3-Dipoles with Knoevenagel Adducts

Yang

Li²,

Wang

et al. 2023

Molecules

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Asymmetric Synthesis of Spirooxindole Lactones by Ammonium-tethered Chiral Organocatalysts catalyzed Michael Addition/Cyclization of 3- hydroxyoxindoles with α,β-unsaturated Aldehydes

Graham

Mills

et al. 2023

CCAT

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background: The asymmetric Michael addition/cyclization reaction of 3-hydroxyoxindoles with α,β-unsaturated aldehydes is an important method for the synthesis of chiral spirooxindole derivatives, which are found in a wide range of biologically active natural products and pharmaceutical agents. objective: Organocatalyzed asymmetric Michael addition/cyclization reactions are one of the most powerful and effective approaches for the construction of complex molecules from relatively simple starting materials. However, a major problem associated with these organocatalytic system is that high catalyst loading and organic solvents are required. In the present work, our objective was to develop a water-compatible organocatalyst that aimed at lowering catalyst loading and being active in aqueous system. method: In a typical experiment, To a solution of catalyst 2a (0.008 mmol) and PhCO2H (0.096 mmol) in 0.5 mL of a mixture solvent iPrOH/H2O (1:3) was added α,β-unsaturated aldehyde (0.4 mmol) and 3-hydroxyoxindole (0.8 mmol). The reaction mixture was proceeded at room temperature for 16 hours, and then was extracted with 10 mL dichloromethane to give the cyclized hemiacetal, which was subjected to the direct oxidation with pyridinium chlorochromate (PCC, 1.2 mmol) for 16 hours to give the desire spirooxindole lactones. result: The reactions were successful to give spirooxindole lactones in high to excellent yields (81-95%) with moderate to excellent enantioselectivities (up to 99 conclusion: The asymmetric Michael addition/cyclization reaction of α,β-unsaturated aldehydes with 3-hydroxyoxindole using ammonium-tethered pyrrolidine-based organocatalyst has been developed. The reaction was performed in aqueous media with low catalyst loading (2 mol%) and provided the spirooxidole lactones in high yields (81-95%) with high enantioselectivities (ee: up to 99%).

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Organocatalytic Asymmetric Reaction between α‐Cyano Enones and Dioxindoles: Synthesis of Dihydrofuran‐Spirooxindoles

Cited by 2 publications

References 49 publications

K2CO3-Promoted Formal [3+3]-Cycloaddition of N-Unsubstituted Isatin N,N′-Cyclic Azomethine Imine 1,3-Dipoles with Knoevenagel Adducts

K2CO3-Promoted Formal [3+3]-Cycloaddition of N-Unsubstituted Isatin N,N′-Cyclic Azomethine Imine 1,3-Dipoles with Knoevenagel Adducts

Asymmetric Synthesis of Spirooxindole Lactones by Ammonium-tethered Chiral Organocatalysts catalyzed Michael Addition/Cyclization of 3- hydroxyoxindoles with α,β-unsaturated Aldehydes

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