He Ting, On Ivan Keng Wee, Bi Shuai, Huang Ziyue, Guo Jingjing, Wang Zhifang, Zhao Yanli
School of Chemistry, Chemical Engineering and Biotechnology, Nanyang Technological University, 21 Nanyang Link, Singapore, 637371, Singapore.
Department of Chemistry, Faulty of Science, National University of Singapore, 3 Science Drive 3, Singapore, 117543, Singapore.
Angew Chem Int Ed Engl. 2024 Jul 8;63(28):e202405769. doi: 10.1002/anie.202405769. Epub 2024 May 29.
The construction of olefin-linked chiral covalent organic frameworks (COFs) with high crystallinity is highly desirable while remains great challenge due to the poor reversibility of the formation reaction for the olefin linkages during the in situ structural self-healing process. Herein, we successfully synthesized two sets of enantiomeric olefin-linked COFs. The chiral catalytic groups are uniformly distributed on the pore walls of COFs, resulting in the full exposure of catalytic sites to the reactants in asymmetric catalysis. The as-prepared (R)/(S)-CCOF8 exhibits excellent catalytic performance with exceeding 99 % enantiomeric excess in the enantioselective electrophilic amination reaction. Moreover, the heterogeneous chiral catalysts are conveniently recycled and could maintain the performance after ten catalytic cycles. Our findings expand the scope to construct stable and crystalline chiral COFs for the asymmetric catalysis.
构建具有高结晶度的烯烃连接的手性共价有机框架（COF）是非常理想的，但由于原位结构自修复过程中烯烃连接形成反应的可逆性差，这仍然是一个巨大的挑战。在此，我们成功合成了两组对映体烯烃连接的COF。手性催化基团均匀分布在COF的孔壁上，使得催化位点在不对称催化中能够完全暴露于反应物。所制备的（R）/（S）-CCOF8在对映选择性亲电胺化反应中表现出优异的催化性能，对映体过量超过99%。此外，这种多相手性催化剂易于回收，并且在十个催化循环后仍能保持性能。我们的发现扩展了构建用于不对称催化的稳定且结晶的手性COF的范围。
