ICIQ-Institute of Chemical Research of Catalonia the Barcelona Institute of Science and Technology, Avenida Països Catalans 16, 43007, Tarragona, Spain.
ICREA-, Passeig Lluís Companys 23, 08010, Barcelona, Spain.
Angew Chem Int Ed Engl. 2021 Mar 1;60(10):5357-5362. doi: 10.1002/anie.202014876. Epub 2021 Jan 28.
Herein, we report a general iminium ion-based catalytic method for the enantioselective conjugate addition of carbon-centered radicals to aliphatic and aromatic enals. The process uses an organic photoredox catalyst, which absorbs blue light to generate radicals from stable precursors, in combination with a chiral amine catalyst, which secures a consistently high level of stereoselectivity. The generality of this catalytic platform is demonstrated by the stereoselective interception of a wide variety of radicals, including non-stabilized primary ones which are generally difficult to engage in asymmetric processes. The system also served to develop organocatalytic cascade reactions that combine an iminium-ion-based radical trap with an enamine-mediated step, affording stereochemically dense chiral products in one-step.
在此，我们报告了一种基于亚胺离子的通用催化方法，用于对脂肪族和芳香族烯醛的碳中心自由基的对映选择性共轭加成。该过程使用有机光氧化还原催化剂，它吸收蓝光从稳定的前体中产生自由基，与手性胺催化剂结合，确保始终保持高水平的立体选择性。该催化平台的通用性通过对各种自由基的立体选择性拦截得到证明，包括通常难以参与不对称过程的非稳定的一级自由基。该体系还用于开发有机催化级联反应，将基于亚胺离子的自由基捕获与烯胺介导的步骤结合在一起，一步即可获得立体密度高的手性产物。
