Asymmetric Tandem 1,5‐Hydride Shift/Ring Closure for the Synthesis of Chiral Spirooxindole Tetrahydroquinolines |
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Authors: | Weidi Cao Prof Dr Xiaohua Liu Jing Guo Dr Lili Lin Prof Dr Xiaoming Feng |
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Institution: | Key Laboratory of Green Chemistry and Technology, Ministry of Education, College of Chemistry, Sichuan University, Chengdu 610064(China), Fax: (+86)?28‐85418249 |
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Abstract: | The direct functionalization of sp3 C?H bonds through a tandem 1,5‐hydride shift/ring closure is described. Various optically active spirooxindole tetrahydroquinoline derivatives bearing contiguous quaternary or tertiary stereogenic carbon centers were readily synthesized. A chiral scandium complex of N,N′‐dioxide promoted the reactions in good yields (up to 97 %) with excellent diastereoselectivities (>20:1) and enantioselectivities (up to 94 % ee). Kinetic isotope effect (KIE) experiments and internal redox reactions of chiral substrates were conducted, and the results provided intriguing information that helped clarify the mechanism of the reaction. |
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Keywords: | asymmetric catalysis C H functionalization hydride shift scandium spirooxindoles |
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