Nickel(II)‐Catalyzed Asymmetric Propargyl [2,3] Wittig Rearrangement of Oxindole Derivatives: A Chiral Amplification Effect |
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| Authors: | Xi Xu Jianlin Zhang Prof?Dr Shunxi Dong Prof?Dr Lili Lin Xiaobin Lin Prof?Dr Xiaohua Liu Prof?Dr Xiaoming Feng |
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| Institution: | 1. Key Laboratory of Green Chemistry & Technology, Ministry of Education, College of Chemistry, Sichuan University, Chengdu, China;2. Collaborative Innovation Center of Chemical Science and Engineering, Tianjin, China |
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| Abstract: | A highly enantioselective 2,3] Wittig rearrangement of oxindole derivatives was realized by using a chiral N,N′‐dioxide/NiII complex as the catalyst under mild reaction conditions. A strong chiral amplification effect was observed, and allowed access to chiral 3‐hydroxy 3‐substituted oxindoles bearing allenyl groups in high yields and enantioselectivities (up to 92 % ee) by using a ligand with only 15 % ee. A reasonable explanation was given based on the experimental investigations and X‐ray crystal structures of enantiomerically pure and racemic catalysts. Moreover, the first catalytic kinetic resolution of racemic oxindole derivatives by a 2,3] Wittig rearrangement was realized with high efficiency and stereoselectivity. |
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| Keywords: | allenes asymmetric catalysis kinetic resolution nickel rearrangements |
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