Catalytic Asymmetric Synthesis of Tetrahydrofuran Spirooxindoles via a Dinuclear Zinc Catalyst
Ya-Jun Guo1, Xin Guo1, De-Zhi Kong1
1College of Chemistry and Institute of Green Catalysis, Zhengzhou University, No. 100, Science Road, Zhengzhou, Henan 450000, P. R. China.
Abstract:
An asymmetric Michael/hemiketalization and Fridel-Crafts reaction has been reported through a one-pot reaction. A number of structurally novel tetrahydrofuran spirooxindoles are synthesized in the presence of a 10 mol % dinuclear zinc catalyst with diastereomer ratios (dr) of 3:1-13:1 and an enantiomeric excess (ee) of 75-99%. The reaction can be performed on a gram scale without impacting its efficiency. The absolute configuration of products is confirmed by X-ray single crystal structure analysis, and a possible mechanism is proposed.
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