Key points are not available for this paper at this time.
Spirocyclopropanes: Only one out of eight possible stereoisomers was obtained in the asymmetric cascade cyclopropanation of alkylidene oxindoles with ethyl 2-chloroacetoacetate. Improved catalyst design ensured that spirocyclopropyl oxindoles featuring two quaternary centers were synthesized in high yield and high enantio- and diastereoselectivity (see scheme).
Noole et al. (2012) studied this question.