Catalytic asymmetric synthesis of polysubstituted spirocyclopropyl oxindoles: organocatalysis versus transition metal catalysis
Spirocyclopropyl oxindoles are widely present in natural products and bioactive molecules. In addition, they play a significant role as a type of donor–acceptor (DA) cyclopropanes in catalytic reactions. Four distinct pathways have been developed for the asymmetric synthesis of this framework, which nicely show the potential of organocatalytic and metal catalyzed asymmetric cyclopropanation in the creation of spirocyclic compounds. This minireview summarizes these complementary methods to synthesise optically active spirocyclopropyl oxindoles bearing various functional groups, discusses the difference and advantages of each method, and summarizes synthetic opportunities that still exist.
- This article is part of the themed collection: 2015 Organic Chemistry Frontiers Review-type Articles