Hu Yang, Lang Kai, Tao Jingran, Marshall McKenzie K, Cheng Qigan, Cui Xin, Wojtas Lukasz, Zhang X Peter
Department of Chemistry, University of South Florida, Tampa, FL, 33620, USA.
Department of Chemistry, Merkert Chemistry Center, Boston College, Chestnut Hill, MA, 02467, USA.
Angew Chem Int Ed Engl. 2019 Feb 25;58(9):2670-2674. doi: 10.1002/anie.201812379. Epub 2019 Feb 4.
Novel D -symmetric chiral amidoporphyrins with alkyl bridges across two chiral amide units on both sides of the porphyrin plane (designated "HuPhyrin") have been effectively constructed in a modular fashion to permit variation of the bridge length. The Co complexes of HuPhyrin, [Co(HuPhyrin)], represent new-generation metalloradical catalysts where the metal-centered d-radical is situated inside a cavity-like ligand with a more rigid chiral environment and enhanced hydrogen-bonding capability. As demonstrated with cyclopropanation and aziridination as model reactions, the bridged [Co(HuPhyrin)] functions notably different from the open catalysts, exhibiting significant enhancement in both reactivity and stereoselectivity. Furthermore, the length of the distal alkyl bridge can have a remarkable influence on the catalytic properties.
新型D对称手性酰胺基卟啉通过在卟啉平面两侧的两个手性酰胺单元上跨接烷基桥（命名为“HuPhyrin”）以模块化方式有效构建，从而允许桥长变化。HuPhyrin的钴配合物[Co(HuPhyrin)]代表新一代金属自由基催化剂，其中以金属为中心的d自由基位于具有更刚性手性环境和增强氢键能力的腔状配体内部。以环丙烷化和氮杂环丙烷化作为模型反应表明，桥连的[Co(HuPhyrin)]的功能与开放型催化剂明显不同，在反应性和立体选择性方面均表现出显著增强。此外，远端烷基桥的长度对催化性能有显著影响。
