10.1021/acs.joc.5b02088.s002 Peng-Ju Xia Peng-Ju Xia Yan-Hua Sun Yan-Hua Sun Jun-An Xiao Jun-An Xiao Zhao-Fang Zhou Zhao-Fang Zhou Sai-Shuai Wen Sai-Shuai Wen Yu Xiong Yu Xiong Guang-Chuan Ou Guang-Chuan Ou Xiao-Qing Chen Xiao-Qing Chen Hua Yang Hua Yang Regioselectivity-Tunable Self-1,3-Dipolar [3+3] Cyclizations of Azomethine Ylides To Assemble Dispirooxindole-piperazines American Chemical Society 2015 isomer skeleton series Cyclization amines regioselectivity azomethine ylides cyclization scaffold diastereoselectivity tetrahydroisoquinoline pyrrolidine substrate cyclic Azomethine Ylides isatin glycine methyl ester 2015-11-20 00:00:00 Dataset https://acs.figshare.com/articles/dataset/Regioselectivity_Tunable_Self_1_3_Dipolar_3_3_Cyclizations_of_Azomethine_Ylides_To_Assemble_Dispirooxindole_piperazines/2106709 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).