title: Regioselectivity-Tunable Self-1,3-Dipolar [3+3] Cyclizations of Azomethine Ylides To Assemble Dispirooxindole-piperazines.
abstract: A series of novel 2,3- or 2,5-dispirooxindole-piperazine ring systems were efficiently constructed through the acid-promoted self-1,3-dipolar [3+3] cyclizations of azomethine ylides derived from isatin with various primary or cyclic secondary amines. Interestingly, the regioselectivity of this self-[3+3] cyclization could be effectively tuned by varying the structural features of substrates. The unprecedented 2,5-dispirooxindole-piperazine skeleton was achieved in good diastereoselectivity by employing 1,2,3,4-tetrahydroisoquinoline, while using pyrrolidine or glycine methyl ester furnished the 2,3-dispirooxindole-piperazine scaffold in excellent diastereoselectivity (only a single isomer formed).
authors.affiliation: College of Chemistry and Chemical Engineering, Central South University , Changsha 410083, P. R. China.
authors.forename: Peng-Ju
authors.initials: PJ
authors.lastname: Xia
authors.affiliation: College of Chemistry and Chemical Engineering, Central South University , Changsha 410083, P. R. China.
authors.forename: Yan-Hua
authors.initials: YH
authors.lastname: Sun
authors.affiliation: College of Chemistry and Chemical Engineering, Central South University , Changsha 410083, P. R. China.
authors.forename: Jun-An
authors.initials: JA
authors.lastname: Xiao
authors.affiliation: College of Chemistry and Chemical Engineering, Central South University , Changsha 410083, P. R. China.
authors.forename: Zhao-Fang
authors.initials: ZF
authors.lastname: Zhou
authors.affiliation: College of Chemistry and Chemical Engineering, Central South University , Changsha 410083, P. R. China.
authors.forename: Sai-Shuai
authors.initials: SS
authors.lastname: Wen
authors.affiliation: College of Chemistry and Chemical Engineering, Central South University , Changsha 410083, P. R. China.
authors.forename: Yu
authors.initials: Y
authors.lastname: Xiong
authors.affiliation: Department of Biology and Chemistry, Hunan University of Science and Engineering , Yongzhou, Hunan 425100, P. R. China.
authors.forename: Guang-Chuan
authors.initials: GC
authors.lastname: Ou
authors.affiliation: College of Chemistry and Chemical Engineering, Central South University , Changsha 410083, P. R. China.
authors.forename: Xiao-Qing
authors.initials: XQ
authors.lastname: Chen
authors.affiliation: College of Chemistry and Chemical Engineering, Central South University , Changsha 410083, P. R. China.
authors.forename: Hua
authors.initials: H
authors.lastname: Yang