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Updated: Jun 14, 2026

Efficient Construction of Drug-like Bispirocyclic Scaffolds Via Organocatalytic Cycloadditions of α-Imino γ-Lactones and Alkylidene Pyrazolones
Published on: February 7, 2019
An efficient stereoselective synthesis of 3-spirocyclopentene- and 3-spiropyrazole-2-oxindoles via 1,3-dipolar
Kodirajan Selvakumar1, Vadivel Vaithiyanathan, Ponnusamy Shanmugam
1Chemical Sciences and Technology Division, National Institute for Interdisciplinary Science and Technology, Trivandrum-695 019, Kerala, India.
Abstract:
The chemistry phosphorus and sulfur ylides have been exploited for a facile, short and efficient synthesis of 3-spirocyclopentene- and 3-spiropyrazole-2-oxindoles from E- and Z-isomers of bromo derivatives of Morita-Baylis-Hillman adducts of isatin with Ph(3)P/activated alkene/K(2)CO(3) and Me(2)S/DEAD/K(2)CO(3), respectively, via [3 + 2]-annulation strategy.
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Preparation of Epoxides
Epoxides result from alkene oxidation, which can be achieved by a) air, b) peroxy acids, c) hypochlorous acids, and d) halohydrin cyclization.
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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