Wang Ze-Shu, Zhu Lu-Jing, Li Cui-Ting, Liu Bin-Yang, Hong Xin, Ye Long-Wu
State Key Laboratory of Physical Chemistry of Solid Surfaces, Key Laboratory of Chemical Biology of Fujian Province, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, 361005, China.
Center of Chemistry for Frontier Technologies, Department of Chemistry, State Key Laboratory of Clean Energy Utilization, Zhejiang University, Hangzhou, 310027, China.
Angew Chem Int Ed Engl. 2022 May 9;61(20):e202201436. doi: 10.1002/anie.202201436. Epub 2022 Mar 16.
In recent years, asymmetric catalysis of ynamides has attracted much attention, but these reactions mostly constructed central chirality, except for a few examples on the synthesis of axially chiral compounds which exclusively relied on noble-metal catalysis. Herein, a facile access to axially chiral N-heterocycles enabled by chiral Brønsted acid-catalyzed 5-endo-dig cyclization of ynamides is disclosed, which represents the first metal-free protocol for the construction of axially chiral compounds from ynamides. This method allows the practical and atom-economical synthesis of valuable N-arylindoles in excellent yields with generally excellent enantioselectivities. Moreover, organocatalysts and ligands based on such axially chiral N-arylindole skeletons are demonstrated to be applicable to asymmetric catalysis.
近年来，烯炔酰胺的不对称催化备受关注，但除了少数仅依赖贵金属催化合成轴手性化合物的例子外，这些反应大多构建的是中心手性。在此，我们报道了一种通过手性布朗斯特酸催化烯炔酰胺的5-内型-环化反应简便合成轴手性氮杂环的方法，这是首例从烯炔酰胺构建轴手性化合物的无金属方法。该方法能够以优异的产率和普遍出色的对映选择性，实现有价值的N-芳基吲哚的实用且原子经济的合成。此外，基于这种轴手性N-芳基吲哚骨架的有机催化剂和配体被证明可用于不对称催化。
