Xu Yang, Pandit Neeraj Kumar, Meraviglia Silvia, Boos Philipp, Stark Paula Anna Maria, Surke Max, Herbst-Irmer Regine, Stalke Dietmar, Ackermann Lutz
Wöhler Research Institute for Sustainable Chemistry (WISCh), Georg-August-Universität Göttingen Tammannstraße 2, Göttingen 37077, Germany.
Institute of Inorganic Chemistry, Georg-August-Universität Göttingen, Tammannstraße 4, Göttingen 37077, Germany.
ACS Catal. 2025 Jun 23;15(13):11716-11725. doi: 10.1021/acscatal.5c03002. eCollection 2025 Jul 4.
-/-disubstituted multichiral [2.2]-paracyclophanes (PCPs) represent privileged scaffolds for asymmetric catalysis, finding extensive applications as chiral ligands in organic synthesis and functional materials. However, enantioselective C-H activation strategies for accessing these structurally demanding molecules remain largely underexplored. We report a synergistic strategy combining photoredox catalysis with enantioselective cobalt-catalyzed C-H activation that enables efficient construction of central chiral and planar chiral PCP derivatives through kinetic resolution. This method provides access to diverse disubstituted multichiral PCPs in good yields with exceptional levels of enantioselectivity (>20:1 dr, >99% ee) while simultaneously recovering the unreacted enantiomer in a high optical purity (up to 50% yield, >99% ee). Computational studies reveal the favorable pathway for a single enantiomer of the racemic PCP, rationalizing the observed enantioselectivity in terms of attractive dispersion interactions emerging as key contributors during the enantiodetermining step. The synthetic utility is demonstrated through: (1) gram-scale continuous photoflow synthesis with maintained efficiency and (2) versatile downstream functionalization of the products into valuable PCP-based ligands. Our findings represent a paradigm shift for the synthesis of sterically congested chiral PCP architectures, significantly expanding the toolbox for asymmetric synthesis and chiral material design.
-/-二取代多手性[2.2]对环芳烷(PCPs)是不对称催化的优势骨架,在有机合成和功能材料中作为手性配体有广泛应用。然而,用于合成这些结构复杂分子的对映选择性C-H活化策略在很大程度上仍未得到充分探索。我们报道了一种将光氧化还原催化与对映选择性钴催化C-H活化相结合的协同策略,该策略能够通过动力学拆分高效构建中心手性和平面手性PCP衍生物。该方法能够以良好的产率获得多种二取代多手性PCP,对映选择性极高(>20:1 dr,>99% ee),同时能以高光学纯度回收未反应的对映体(产率高达50%,>99% ee)。计算研究揭示了外消旋PCP单一映体的有利反应途径,从对映体决定步骤中起关键作用的有吸引力的色散相互作用方面解释了观察到的对映选择性。通过以下方式证明了该合成方法的实用性:(1)克级连续光流合成且效率保持不变;(2)将产物进行多功能下游官能化,转化为有价值的基于PCP的配体。我们的研究结果代表了空间拥挤的手性PCP结构合成的范式转变,显著扩展了不对称合成和手性材料设计的工具库。