Asymmetric Aminocatalysis Combined with Iodine Catalysis: One-Pot Sequential Catalytic Approach to Access Chiral
Pooja Goyal1,2, Akhil K Dubey1, Raghunath Chowdhury1,2
1Bio-Organic Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400085, India.
Abstract:
Herein, a sequential catalytic system combining asymmetric aminocatalysis with iodine catalysis is introduced. This newly catalytic system promotes a Michael/iodization/nucleophilic substitution reaction to provide enantioenriched novel spirodihydrobenzofuran-pyrazolones from o-hydroxy enones and pyrazolones. The desired products are realized in moderate to good yields with good diastereoselectivities and high enantioselectivities. This one-pot method features the formation of contiguous stereocenters, of which one is the spiro-quaternary stereocenter, engagement of less reactive electrophiles, mild reaction conditions, and scalability. Importantly, the reported protocol provides a mechanistically distinct pathway to construct enantioenriched spirodihydrobenzofuran-pyrazolones.
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