Luo Pengfei, Li Jinxia, Deng Yu-Hua, Yu Peiyuan, Wang Yingcheng, Peng Fangzhi, Shao Zhihui
Key Laboratory of Medicinal Chemistry for Natural Resource, Ministry of Education, School of Chemical Science and Technology, and State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Yunnan University, Kunming, 650500, China.
Department of Chemistry and Shenzhen Grubbs Institute, Guangdong Provincial Key Laboratory of Catalysis, Southern University of Science and Technology, Shenzhen, Guangdong, 518055, China.
Angew Chem Int Ed Engl. 2024 Nov 4;63(45):e202412179. doi: 10.1002/anie.202412179. Epub 2024 Sep 3.
Here, we report a strategy enabling triple switchable chemo-, regio-, and stereodivergence in newly developed palladium-catalyzed cycloadditions of allenes. An asymmetric pseudo-stereodivergent cycloaddition of allenes bearing a primary leaving group at the α-position, where a dynamic kinetic asymmetric hydroalkoxylation of racemic unactivated allenes was the enantio-determining step, is realized, providing four stereoisomers [(Z,R), (Z,S), (E,S), and (E,R)] containing a di-substituted alkene scaffold and a stereogenic center. By tuning reaction conditions, a mechanistically distinctive cycloaddition is uncovered selectively with the same set of substrates. By switching the position of the leaving group of allenes, a cycloaddition involving an intermolecular O-attack is disclosed. Diverse mechanisms of the cycloaddition reactions of allenes enable rapid access to structurally and stereochemically diverse 3,4-dihydro-2H-1,4-benzoxazines in high efficiency and selectivity.
在此，我们报道了一种策略，该策略能够在新开发的钯催化的丙二烯环加成反应中实现化学、区域和立体发散的三重切换。实现了在α位带有一级离去基团的丙二烯的不对称假立体发散环加成反应，其中外消旋未活化丙二烯的动态动力学不对称氢烷氧基化是对映体决定步骤，提供了包含二取代烯烃骨架和一个立体中心的四种立体异构体[(Z,R)、(Z,S)、(E,S)和(E,R)]。通过调节反应条件，利用同一组底物选择性地发现了一种机理独特的环加成反应。通过切换丙二烯离去基团的位置，公开了一种涉及分子间O-进攻的环加成反应。丙二烯环加成反应的多种机制使得能够高效且选择性地快速获得结构和立体化学多样的3,4-二氢-2H-1,4-苯并恶嗪。
