Enantioselective and Diastereoselective Synthesis of Multisubstituted Spirocyclopentane Oxindoles through NHC Catalysis.
The highly enantio- and diastereoselective N-heterocyclic carbene-catalyzed [3 + 2] annulation of isatin-derived enals and α-EWG-functionalized chalcones is disclosed. Developed herein is an efficient, operationally simple, and general synthetic protocol for the straightforward construction of spirocyclopentane oxindol...