Highly Enantioselective Construction of Polycyclic Spirooxindoles by Organocatalytic 1,3-Dipolar Cycloaddition of 2-Cyclohexenone Catalyzed by Proline-Sulfonamide

This is an author's peer-reviewed final manuscript, as accepted by the publisher. The published article is copyrighted by John Wiley & Sons, Inc., and can be found at: http://onlinelibrary.wiley.com/journal/10.1002/%28ISSN%291099-0690/issuesAn enantioselective 1,3-dipolar cycloaddition of 2-cyclo-hexene-1-one and azomethine ylide generated in situ from isatin and amino ester was developed by employing proline sulfonamide as the catalyst. Consequently, novel polycyclic spirooxindole scaffolds with three contiguous stereocenters were prepared in high yield (up to 95%) with excellent diastereo- (> 20:1 dr) and enantio-selectivity (up to 99% ee)