河南大学Zhiyong Jiang等与河南师范大学合作团队近日取得一项新成果。利用协同光氧还和手性氢键催化，他们实现了烯基氮杂芳烃的不对称氢氨烷基化反应。2022年1月9日，国际知名学术期刊《德国应用化学》发表了这一成果。

通过手性氢键催化向活化的烯烃不对称共轭加成，这一反应已被广泛用于获得在烯烃活化基团的β位上含有立体中心的对映体富集分子。在该文中，团队报道了以上反应的第一个高度对映选择性的自由基反应模式。在以手性磷酸和DPZ为光氧化还原敏化剂的双有机催化剂体系下，引入了具有CF₃取代的N-芳基甘氨酸可以和烯基氮杂芳烃反应，得到了有价值的氢氨烷基化加合产物，结果令人满意。

此外，在氮杂芳烃的多样性基础上，该方法还可以构建芳基、烷基和硅基取代的立体中心。研究人员还通过控制实验和密度泛函理论计算，阐明了合理的反应机理和立体选择性的起源，其中非经典的H-键相互作用有助于提供充分的对映控制，辅助手性催化剂。

附：英文原文

Title: Asymmetric Hydroaminoalkylation of Alkenylazaarenes via Cooperative Photoredox and Chiral Hydrogen-Bonding Catalysis

Author: Xiangpei Chai, Xinheng Hu, Xiaowei Zhao, Yanli Yin, Shanshan Cao, Zhiyong Jiang

Issue&Volume: 2022-01-09

Abstract: Chiral hydrogen-bonding (H-bonding) catalytic asymmetric conjugate addition to activated olefins has been widely used to access enantioenriched molecules containing stereocentres at the β-position of the olefin activating groups. Herein, we report the first highly enantioselective radical-based manifold. Under a dual organocatalyst system involving a chiral phosphoric acid and DPZ as the photoredox sensitizer, transformations of N-arylglycines, in which aryls with CF3 substituents are introduced, with alkenyl azaarenes afforded valuable hydroaminoalkylation adducts with satisfactory results. In addition to the diversity of azaarenes, the method can be used to construct aryl-, alkyl- and silyl-substituted stereocentres. Control experiments and density functional theory calculations were performed to elucidate a plausible reaction mechanism and the origin of stereoselectivity, wherein nonclassical H-bonding interactions were found to assist chiral catalysts in offering sufficient enantiocontrol.

DOI: 10.1002/anie.202115110

Source: https://onlinelibrary.wiley.com/doi/10.1002/anie.202115110