英国曼彻斯特大学Daniele Leonori团队开发了利用胺基自由基sp3 C-H键氯化的实用性和选择性策略。 相关研究成果于2021年1月18日发表于国际一流学术期刊《德国应用化学》。

在有机分子中引入氯原子对于工业化学品的制造、高级合成中间体的开发以及药物、农用化学品和聚合物的物理化学和生物特性的微调都是至关重要的。

该文中，研究人员开发了一种能使SP3 C–H键位置选择性氯化的通用和实用的光化学策略。该工艺利用质子化N-氯胺作为胺基自由基前体和自由基氯化剂的能力。

光化学引发后，由于大量的相容功能性，建立了允许广泛底物功能化的有效自由基链传播。通过适当选择胺基自由基，协同最大化氢原子转移过渡态的极性和空间效应的能力为自由基sp3C-H氯化提供了已知的最高选择性。

附：英文原文

Title: Practical and Selective sp3 C–H Bond Chlorination via Aminium Radicals

Author: Alastair J. McMillan, Martyna Sie&#x, Piero Di Lorenzo, Gemma K. Gransbury, Nicholas Chilton, Michela Salamone, Alessandro Ruffoni, Massimo Bietti, Daniele Leonori

Issue&Volume: 18 January 2021

Abstract: 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  3  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  3  C–H chlorination.

DOI: 10.1002/anie.202100030

Source: https://onlinelibrary.wiley.com/doi/10.1002/anie.202100030