One-Pot Asymmetric Synthesis of Spiropyrazolone-Linked Cyclopropanes and Benzofurans through a General Michael Addition/Chlorination/Nucleophilic Substitution Sequence

A sequential and general strategy
has been successfully developed
for the synthesis of spiropyrazolone scaffolds. This intriguing transformation
of the asymmetric multicomponent catalysis process was realized with
the combination of Michael addition/chlorination/nucleophilic substitution
in a one-pot sequence, giving rise to a series of spiropyrazolones
with fully substituted cyclopropanes and spiro-dihydrobenzofurans
containing continuous stereogenic centers in good yields with excellent
stereoselectivities.