title: Organocatalytic Asymmetric Michael/Cyclization Cascade Reactions of 3-Hydroxyoxindoles/3-Aminooxindoles with α,β-Unsaturated Acyl Phosphonates for the Construction of Spirocyclic Oxindole-γ-lactones/lactams.
abstract: Enantioselective Michael/cyclization cascade reactions of 3-hydroxyoxindoles/3-aminooxindoles with α,β-unsaturated acyl phosphonates by using a cinchonine derived squaramide as the catalyst were developed. A broad range of spirocyclic oxindole-γ-lactones/lactams could be obtained in moderate to excellent yields (up to 98%) with good to excellent diastereo- and enantioselectivities (up to >99:1 dr and 97% ee) under mild conditions. This work represents the first example about the α,β-unsaturated acyl phosphonates for the asymmetric construction of spirocyclic oxindoles.
authors.affiliation: College of Chemistry and Materials Sciences, Guizhou Normal University , Guiyang 550001, China.
authors.forename: Lin
authors.initials: L
authors.lastname: Chen
authors.forename: Zhi-Jun
authors.initials: ZJ
authors.lastname: Wu
authors.affiliation: University of Chinese Academy of Sciences , Beijing 100049, China.
authors.forename: Ming-Liang
authors.initials: ML
authors.lastname: Zhang
authors.affiliation: University of Chinese Academy of Sciences , Beijing 100049, China.
authors.forename: Deng-Feng
authors.initials: DF
authors.lastname: Yue
authors.forename: Xiao-Mei
authors.initials: XM
authors.lastname: Zhang
authors.forename: Xiao-Ying
authors.initials: XY
authors.lastname: Xu
authors.forename: Wei-Cheng
authors.initials: WC
authors.lastname: Yuan