Catalytic asymmetric [3 + 2]-cycloaddition for stereodivergent synthesis of chiral indolyl-pyrrolidines.

The stereochemical divergent synthesis of indolyl-pyrrolidines was accomplished using an imidazoline-aminophenol (IAP)-Ni(OAc)2 complex and a bis(imidazolidine)pyridine (PyBidine)-Cu(OTf)2 complex. The former catalyzed exo'-selective asymmetric [3 + 2] cyclization of iminoesters with indolyl nitroalkenes, and the latter catalyzed the reaction in an endo-selective manner. These catalysts are tolerant toward highly functional substrates that supply chiral indolyl-pyrrolidine hybrids.