Faculty of Pharmacy, Keio University.
Institute of Microbial Chemistry.
Chem Pharm Bull (Tokyo). 2022;70(9):595-598. doi: 10.1248/cpb.c22-00215.
An iterative hydride reduction/oxidation process was promoted under ambient conditions by a quasi-planar iminium cation rigidified by two concatenated quinoline units. The iminium proton was fixed by hydrogen bonding from neighboring quinoline nitrogen atoms, rendering the imine highly susceptible to hydride reduction with weak reductants, e.g., 1,4-dihydropyridines. The thus-formed amine was readily oxidized by molecular oxygen to regenerate the quasi-planar iminium cation under ambient conditions. This process was exploited for catalytic oxidation of 1,4-dihydropyridines as well as 9,10-dihydroacridine to highlight an intriguing rigidity-driven catalysis.
在环境条件下，通过由两个串联的喹啉单元刚性化的准平面亚胺阳离子促进了迭代氢化物还原/氧化过程。亚胺质子通过来自相邻喹啉氮原子的氢键固定，使亚胺极易与弱还原剂（例如 1,4-二氢吡啶）发生氢化物还原。形成的胺很容易被分子氧氧化，在环境条件下再生准平面亚胺阳离子。该过程用于催化氧化 1,4-二氢吡啶以及 9,10-二氢吖啶，以突出引人入胜的刚性驱动催化作用。
