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

R. L. Graham,

K. Mills,

Allan D. Headley

et al.

Current Catalysis, Journal Year: 2023, Volume and Issue: 12(1), P. 34 - 42

Published: April 1, 2023

Abstract: The ammonium-tethered pyrrolidine-based organocatalyst catalyzed asymmetric Michael addition/cyclization reaction of α,β-unsaturated aldehydes with 3-hydroxyoxindole in aqueous media was developed, giving the spirooxidole lactones high yields enantioselectivities. Background: 3-hydroxyoxindoles α,β- unsaturated is an important method for synthesis chiral spirooxindole derivatives, which are found a wide range biologically active natural products and pharmaceutical agents. Objective: Organocatalyzed reactions one most powerful effective approaches construction complex molecules from relatively simple starting materials. However, major problem associated these organocatalytic system that catalyst loading organic solvents required. In present work, our objective to develop water-compatible aimed at lowering being system. Methods: typical experiment, To solution 2a (0.008 mmol) PhCO2H (0.096 0.5 mL mixture solvent iPrOH/H2O (1:3) added aldehyde (0.4 (0.8 mmol). proceeded room temperature 16 hours, then extracted 10 dichloromethane give cyclized hemiacetal, subjected direct oxidation pyridinium chlorochromate (PCC, 1.2 hours desired lactones. Results: successfully gave excellent (81-95%) moderate enantioselectivities (up 99% ee). diastereoselectivities were poor ranging 1:1.1 1:2.3. Conclusion: using has been developed. performed low (2 mol%) provided (ee: up 99%).

Language: Английский

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

Guosheng Yang,

Sicheng Li,

Qiumi Wang

et al.

Molecules, Journal Year: 2023, Volume and Issue: 28(3), P. 1034 - 1034

Published: Jan. 19, 2023

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

Language: Английский

Citations

2
Asymmetric Synthesis of Spirooxindole Lactones by Ammonium-tethered Chiral Organocatalysts catalyzed Michael Addition/Cyclization of 3- hydroxyoxindoles with α,β-unsaturated Aldehydes DOI

R. L. Graham,

K. Mills,

Allan D. Headley

et al.

Current Catalysis, Journal Year: 2023, Volume and Issue: 12(1), P. 34 - 42

Published: April 1, 2023

Abstract: The ammonium-tethered pyrrolidine-based organocatalyst catalyzed asymmetric Michael addition/cyclization reaction of α,β-unsaturated aldehydes with 3-hydroxyoxindole in aqueous media was developed, giving the spirooxidole lactones high yields enantioselectivities. Background: 3-hydroxyoxindoles α,β- unsaturated is an important method for synthesis chiral spirooxindole derivatives, which are found a wide range biologically active natural products and pharmaceutical agents. Objective: Organocatalyzed reactions one most powerful effective approaches construction complex molecules from relatively simple starting materials. However, major problem associated these organocatalytic system that catalyst loading organic solvents required. In present work, our objective to develop water-compatible aimed at lowering being system. Methods: typical experiment, To solution 2a (0.008 mmol) PhCO2H (0.096 0.5 mL mixture solvent iPrOH/H2O (1:3) added aldehyde (0.4 (0.8 mmol). proceeded room temperature 16 hours, then extracted 10 dichloromethane give cyclized hemiacetal, subjected direct oxidation pyridinium chlorochromate (PCC, 1.2 hours desired lactones. Results: successfully gave excellent (81-95%) moderate enantioselectivities (up 99% ee). diastereoselectivities were poor ranging 1:1.1 1:2.3. Conclusion: using has been developed. performed low (2 mol%) provided (ee: up 99%).

Language: Английский

Citations

1