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Updated: Jun 25, 2026

Efficient Construction of Drug-like Bispirocyclic Scaffolds Via Organocatalytic Cycloadditions of α-Imino γ-Lactones and Alkylidene Pyrazolones
Published on: February 7, 2019
Organocatalytic Enantioselective Desymmetrization Cascade for the Construction of Functionalized
Vikas S Chavan1,2, Shubhranshu Shekhar Sahoo1,2, Rajesh G Gonnade2,3
1Organic Chemistry Division, CSIR-National Chemical Laboratory, Dr. Homi Bhabha Road, Pune 411008, India.
Abstract:
The construction of stereochemically enriched molecules from readily accessible meso and prochiral precursors via catalytic enantioselective desymmetrization represents a powerful synthetic strategy. Herein, we report an efficient enantioselective Michael/oxa-Michael cascade reaction between C4-functionalized meso-2,5-cyclohexadienones and β-ketoesters, catalyzed by a Takemoto chiral squaramide. This protocol enables the efficient construction of densely functionalized oxabicyclo[3.3.1]nonane frameworks bearing two or three stereogenic centers, with good to excellent diastereo- and enantioselectivities. Furthermore, the method is amenable to scale-up and offers opportunities for late-stage functionalization.
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