1. N-Heterocyclic carbene-catalyzed enantioselective hetero-[10 + 2] annulation.
- Author
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Peng, Qiupeng, Li, Shi-Jun, Zhang, Bei, Guo, Donghui, Lan, Yu, and Wang, Jian
- Subjects
ENANTIOSELECTIVE catalysis ,HETEROCYCLIC compounds ,RING formation (Chemistry) ,DENSITY functional theory ,KETONE derivatives - Abstract
Higher-order cycloadditions are a powerful strategy for the construction of polycycles in one step. However, an efficient and concise version for the induction of asymmetry is lacking. N-heterocyclic carbenes are widely used organocatalysts for asymmetric synthesis and could be an ideal choice for enantioselective higher-order cycloadditions. Here, we report an enantioselective [10 + 2] annulation between catalytically formed aza-benzofulvene intermediates and trifluoromethyl ketone derivatives. This protocol exhibits a wide scope, high yields, and good ee values, reflecting a robust and efficient higher-order cycloaddition. Density functional theory calculations provide an accurate prediction of the reaction enantioselectivity, and in-depth insight to the origins of stereocontrol. High-order cycloaddition reactions are useful for the construction of polycycles in a single step, but versions that induce asymmetry are limited. Here the authors report the construction of asymmetric polycycles via N-heterocyclic carbene-catalyzed hetero-[10 + 2] cycloaddition of indole-2-carbaldehydes with trifluoromethyl ketone derivatives. [ABSTRACT FROM AUTHOR]
- Published
- 2020
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