Asymmetric Vinylogous Michael/Oxa-Michael Tandem Reaction between β,γ-Unsaturated Amides and Isatin-Derived β,γ-Unsaturated α-Ketoesters

J Org Chem. 2024 Nov 15. doi: 10.1021/acs.joc.4c02066. Online ahead of print.

Abstract

An organocatalytic asymmetric vinylogous Michael/oxa-Michael tandem reaction between β,γ-unsaturated pyrazoleamides and isatin-derived β,γ-unsaturated ketoesters has been developed with excellent regio-, diastereo-, and enantioselectivities. The methodology provides an effective approach to construct enantiomerically pure 3,4'-pyranyl spirooxindole derivatives containing three contiguous chiral centers. Moreover, the transformations of the chiral products, including the removal and reduction of the pyrazole group, have been investigated.