We report the ()-3,3'-I-BINOL-boron-complex-catalyzed asymmetric 1,3-dipolar cycloaddition of 2'-hydroxychalcones with ,'-cyclic azomethine imines, providing the corresponding ,'-bicyclic pyrazolidine derivatives with three contiguous tertiary stereocenters in high yields with excellent diastereo- and enantioselectivities (up to >99:1 diastereomeric ratio and >99% enantiomeric excess). This catalytic system exhibits advantages of mild reaction conditions, high efficiency, and broad substrate scopes.
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