Switchable Role of C,N-Cyclic Azomethine Imine as an Oxidants in the Divergent Synthesis of Pyrazolidine-Fused Tetrahydroquinolines and C3-Functionalized Quinolines

초록

C,N-cyclic azomethine imines are versatile dipoles in cycloaddition reactions, owing to their facile derivatization into biologically active compounds. In general, they have been employed with electron-poor dipolarophiles, following a normal-electron-demand (NED) based on frontier molecular orbital (FMO) theory. In this work, we explored electron-rich endocyclic N-silyl enamine intermediates as dipolarophiles. Notably, we observed that varying the stoichiometry between the N-silyl enamine intermediates and C,N-cyclic azomethine imines resulted in divergent reaction pathways.