Department of Chemistry, University of Manchester, Oxford Road, Manchester, M13 9PL, UK.
Dipartimento di Scienze e Tecnologie Chimiche, Università "Tor Vergata", Via della Ricerca Scientifica, 00133, Rome, Italy.
Angew Chem Int Ed Engl. 2021 Mar 22;60(13):7132-7139. doi: 10.1002/anie.202100030. Epub 2021 Feb 25.
The introduction of chlorine atoms into organic molecules is fundamental to the manufacture of industrial chemicals, the elaboration of advanced synthetic intermediates and also the fine-tuning of physicochemical and biological properties of drugs, agrochemicals and polymers. We report here a general and practical photochemical strategy enabling the site-selective chlorination of sp C-H bonds. This process exploits the ability of protonated N-chloroamines to serve as aminium radical precursors and also radical chlorinating agents. Upon photochemical initiation, an efficient radical-chain propagation is established allowing the functionalization of a broad range of substrates due to the large number of compatible functionalities. The ability to synergistically maximize both polar and steric effects in the H-atom transfer transition state through appropriate selection of the aminium radical has provided the highest known selectivity in radical sp C-H chlorination.
将氯原子引入有机分子是制造工业化学品、精细合成中间体以及调整药物、农药和聚合物的物理化学和生物性质的基础。我们在这里报告了一种通用且实用的光化学策略，可实现 sp C-H 键的选择性氯化。该过程利用质子化的 N-氯代胺作为铵自由基前体和自由基氯化剂的能力。在光化学引发后，建立了有效的自由基链传播，由于大量兼容的官能团，允许对广泛的底物进行功能化。通过适当选择铵自由基，在 H-原子转移过渡态中协同最大化极性和空间效应的能力为自由基 sp C-H 氯化提供了迄今为止已知的最高选择性。
