Catalytic Asymmetric exo′‐Selective [3+2] Cycloaddition for Constructing Stereochemically Diversified Spiro[pyrrolidin‐3,3′‐oxindole]s

The first catalytic asymmetric exo′-selective [3+2] cycloaddition of methyleneindolinones with iminoesters was achieved for construction of novel diastereomers of spiro[pyrrolidin-3,3′-oxindole]. By using the imidazoline–aminophenol-ligand complex [Ni(OAc)2–(L1)], the reaction proceeds in the stepwise Michael–Mannich reaction to give the exo′ adducts as stable isomers (see scheme).