5599-43-9Relevant academic research and scientific papers
Hydrogen-Bonding-Promoted Cascade Rearrangement Involving the Enlargement of Two Rings: Efficient Access to Polycyclic Quinoline Derivatives
Cao, Wen-Bin,Ji, Shun-Jun,Lan, Yu,Li, Haiyan,Li, Shijun,Xu, Meng-Meng,Xu, Xiao-Ping
supporting information, p. 21425 - 21430 (2020/09/23)
An efficient cascade reaction of tryptamine-derived isocyanides with C,N-cyclic azomethine imines is described. The polycyclic pyrrolo[2,3-c]quinoline derivatives, which benefited from rearrangement process driven by hydrogen bonding, could be directly assembled in moderate to good yields (40–87 %) under metal-free and mild conditions. This transformation involved four new heterocyclic rings formations and uniquely, ring opening of indole as well as ring expansion of C,N-cyclic azomethine imine. Both experimental and DFT studies provided guidance on the in-depth insight into the reaction pathways and hydrogen bonding was identified to lower the free energy barrier in transition states. This work constitutes a rare example of tryptamine-derived isocyanide-based cascade reactions, and potentially could be a powerful synthetic strategy for accessing polycyclic analogues involved in natural products.
Asymmetric dearomatization of indoles through a Michael/Friedel-Crafts-Type cascade to construct polycyclic spiroindolines
Zhao, Xiaohu,Liu, Xiaohua,Mei, Hongjiang,Guo, Jing,Lin, Lili,Feng, Xiaoming
supporting information, p. 4032 - 4035 (2015/03/30)
A highly efficient asymmetric dearomatization of indoles was realized through a cascade reaction between 2-isocyanoethylindole and alkylidene malonates catalyzed by a chiral N,N-dioxide/MgII catalyst. Fused polycyclic indolines containing three stereocenters were afforded in good yields with excellent diastereo- and enantioselectivities through a Michael/Friedel-Crafts/Mannich cascade. When 2-substituted 2-isocyanoethylindoles were used, spiroindoline derivatives were obtained through a Michael/Friedel-Crafts reaction.
