posted on 2022-11-10, 18:35authored byMeng-Lan Luo, Qiumeng Hou, Shuai-Jiang Liu, Qian Zhao, Rui Qin, Cheng Peng, Bo Han, Gu Zhan
Hydropyrrolo[2,3-b]indole is a privileged
indoline
motif, while its analogue, hydropyrrolo[3,2-b]indole,
has been much less explored. Herein, we developed a cascade reaction
of oxindole-derived nitrones with allenoates, providing straightforward
access to the tetracyclic hydropyrrolo[3,2-b]indole
scaffolds. Formation of multiple C–C/C–X bonds and cleavage
could be achieved within one synthetic step using a simple catalyst
(Gimeracil) under mild conditions. The reaction pathway may involve
the generation of spiro-hydroazepinone as the key intermediate.