title: Asymmetric tandem 1,5-hydride shift/ring closure for the synthesis of chiral spirooxindole tetrahydroquinolines.
abstract: The direct functionalization of sp(3) 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.
authors.affiliation: Key Laboratory of Green Chemistry and Technology, Ministry of Education, College of Chemistry, Sichuan University, Chengdu 610064(China), Fax: (+86) 28-85418249.
authors.forename: Weidi
authors.initials: W
authors.lastname: Cao
authors.forename: Xiaohua
authors.initials: X
authors.lastname: Liu
authors.forename: Jing
authors.initials: J
authors.lastname: Guo
authors.forename: Lili
authors.initials: L
authors.lastname: Lin
authors.forename: Xiaoming
authors.initials: X
authors.lastname: Feng
keywords: CH functionalization; asymmetric catalysis; hydride shift; scandium; spirooxindoles