A New Strategy for Enantioselective Construction of Multisubstituted Five‐Membered Oxygen Heterocycles via a Domino Michael/Hemiketalization Reaction |
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| Authors: | Pei‐Jin Huang Xixi Song Prof. Dr. Min‐Can Wang Prof. Dr. Jun‐Biao Chang |
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| Affiliation: | College of Chemistry and Molecular Engineering, Zhengzhou University, 75, Daxue Street, Zhengzhou City, 450052 (China) |
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| Abstract: | A new highly enantioselective domino Michael/hemiketalization reaction of α‐hydroxyacetophenone with β,γ‐unsaturated α‐keto esters for the synthesis of 2,2,4,5‐tetrasubstituted chiral tetrahydrofurans is reported. With 2 mol % intramolecular dinuclear zinc‐AzePhenol complex prepared in situ from the reaction of multidentate semi‐azacrown ether ligand with ZnEt2, the corresponding anti‐multisubstituted tetrahydrofuran products were obtained in up to 90 % yields, and 98 % enantiomeric excess (ee) at 0 °C for 45 min. Moreover, the products were easily converted to 2,3,5‐trisubstituted 2,3‐dihydrofurans without any loss in optical activity. |
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| Keywords: | asymmetric catalysis domino reactions Michael/hemiacetalization reactions tetrahydrofuran zinc |
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