Freund Philip, Pauls Mike, Babushkina Daria, Pickl Thomas, Bannwarth Christoph, Bach Thorsten
School of Natural Sciences, Department Chemie, and Catalysis Research Center (CRC), Technische Universität München, Lichtenbergstrasse 4, 85747 Garching, Germany.
Institut für Physikalische Chemie, RWTH Aachen University, 52074 Aachen, Germany.
J Am Chem Soc. 2025 Jan 15;147(2):1434-1439. doi: 10.1021/jacs.4c16053. Epub 2024 Dec 30.
By coupling a photochemical and a thermal step, a single chiral catalyst can establish a photostationary state in which the enantiopure form of a chiral compound is favored over its racemate. Following this strategy, 3-substituted 4,7-diaza-1-isoindolones were successfully deracemized (74-98% yield, 86-99% ) employing 2.5 mol % of a photocatalyst. Key to the success of the reaction is the fact that a chiral benzophenone recruits selectively one enantiomer of the substrate for a photoinduced hydrogen atom transfer. A combination of computational and experimental studies suggests that the hydrogen atom is shuttled via the oxygen atom of the catalyst to the 4-nitrogen atom of the substrate.
通过结合光化学步骤和热步骤，单一手性催化剂可以建立一种光稳态，其中手性化合物的对映体纯形式比其外消旋体更受青睐。按照这种策略，使用2.5 mol%的光催化剂成功地使3-取代的4,7-二氮杂-1-异吲哚酮进行了消旋化反应（产率74-98%，对映体过量86-99%）。该反应成功的关键在于手性二苯甲酮选择性地募集底物的一种对映体进行光诱导氢原子转移。计算和实验研究相结合表明，氢原子通过催化剂的氧原子穿梭到底物的4-氮原子上。
