Highly functionalized complex molecules are key tools for promoting biochemical research and developing pharmaceuticals, because the network of chiralities, positions of heteroatoms, and direction of lone-pairs in the molecules are strictly linked to their biological activities. Catalytic asymmetric synthesis is the basis and core technology to supply these complex compounds in a stereoselective manner. Here, the catalytic asymmetric [3+2]-cycloaddition of iminoesters and nitroalkenes has been intensively investigated for giving chiral pyrrolidine structures which are observed abundantly in natural products and pharmaceuticals. Although the
endo- or
exo-selective [3+2]-cycloaddition has been widely examined using chiral Cu-catalysts, there is no report on the catalytic asymmetric synthesis of
exo’-adduct. We accomplished the first catalytic asymmetric
exo’-selective [3+2]-cycloaddition of azomethine imines and nitroalkenes using imidazoline-aminophenol (
IAP)-Ni(OAc)
2 complex to give the
exo’-adduct in up to 99% ee. The first catalytic asymmetric
exo’-selective [3+2]-cycloaddition of methyleneindolinones with iminoesters was also achieved by the
IAP-Ni(OAc)
2 complex for the construction of a novel diastereomer of biologically important spiro[pyrrolidin-3,3’-oxindole]. Moreover, a novel
C2-symmetric bis(imidazolidine)pyridine ligand (PyBidine) was easily synthesized in a single condensation of 2,6-pyridyl aldehyde and optically active (
S,
S)-diphenylethylene diamine. The newly developed PyBidine-Cu(OTf)
2 complex enabled the highly
endo-selective [3+2]-cycloaddition of iminoesters with nitroalkenes.
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