Ruthenium(II)/Chiral Brønsted Acid Co‐Catalyzed Enantioselective Four‐Component Reaction/Cascade Aza‐Michael Addition for Efficient Construction of 1,3,4‐Tetrasubstituted Tetrahydroisoquinolines |
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Authors: | Dr. Jun Jiang Xiaochu Ma Dr. Changge Ji Dr. Zhenqiu Guo Taoda Shi Dr. Shunying Liu Prof. Wenhao Hu |
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Affiliation: | Shanghai Engineering Research Center of Molecular Therapeutics and New Drug Development, East China Normal University, Shanghai, 200062 (China), Fax: (+86)?021‐62221237 |
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Abstract: | An elegant synergistic catalytic system comprising a ruthenium complex with a chiral Brønsted acid was developed for a four‐component Mannich/cascade aza‐Michael reaction. The ruthenium‐associated ammonium ylides successfully trapped with in situ generated imines indicates a stepwise process of proton transfer in the ruthenium‐catalyzed carbenoid N?H insertion reaction. The different decomposition abilities of various ruthenium complexes towards diazo compounds were well explained by the calculated thermodynamic data. The transformation features a mild, rapid, and efficient method for the synthesis of enantiomerically pure 1,3,4‐tetrasubstituted tetrahydroquinolines bearing a quaternary stereogenic carbon center from simple starting precursors in moderate yields with high diastereo‐ and enantioselectivity. |
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Keywords: | Brø nsted acid multicomponent reactions ruthenium synergistic catalysis tetrahydroisoquinolines |
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