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Updated: Jul 19, 2026

Efficient Construction of Drug-like Bispirocyclic Scaffolds Via Organocatalytic Cycloadditions of α-Imino γ-Lactones and Alkylidene Pyrazolones
Published on: February 7, 2019
Cycloaddition protocol for the assembly of the hexacyclic framework associated with the kopsifoline alkaloids
Xuechuan Hong1, Stefan France, José M Mejía-Oneto
1Department of Chemistry, Emory University, Atlanta, GA 30322, USA.
Researchers developed a new synthetic route for kopsifoline alkaloids using a Rh(II)-catalyzed cascade. This approach efficiently constructs the complex hexacyclic framework, enabling access to these important natural products.
Area of Science:
- Organic Chemistry
- Synthetic Chemistry
- Natural Product Synthesis
Background:
- Kopsifoline alkaloids possess a complex hexacyclic structure.
- Efficient synthetic strategies are needed to access these compounds.
Purpose of the Study:
- To develop a novel synthetic approach to the hexacyclic framework of kopsifoline alkaloids.
- To utilize a Rh(II)-catalyzed cyclization-cycloaddition cascade for efficient skeleton construction.
Main Methods:
- Rh(II)-catalyzed cyclization-cycloaddition cascade reaction.
- Conversion of the cycloadduct to TBS enol ether.
- Oxidation and subsequent reaction with CsF to complete the hexacyclic skeleton.
Main Results:
- Successful construction of the complete hexacyclic skeleton of kopsifolines.
- Development of a key [3+2]-cycloadduct intermediate.
- Efficient transformation of intermediates to the final hexacyclic framework.
Conclusions:
- The developed Rh(II)-catalyzed cascade provides an effective strategy for synthesizing kopsifoline alkaloids.
- This method offers a streamlined route to complex hexacyclic natural product frameworks.
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Epoxidation with Peroxy Acids
Epoxidation of alkenes via oxidation with peroxy acids involves the conversion of a carbon–carbon double bond to an epoxide using the oxidizing agent meta-chloroperoxybenzoic acid, commonly known as MCPBA. Since the O–O bond of peroxy acids is very weak, the addition of electrophilic oxygen of peroxy acids to...
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