Methods for selective C–H bond functionalization have provided chemists with versatile and powerful toolboxes for synthesis, such as the late-stage modification of a lead compound without the need for lengthy de novo synthesis1–5. Cleavage of an sp 3 C–H bond via hydrogen atom transfer (HAT) is particularly useful, given the large number of available HAT acceptors and the diversity of reaction pathways available to the resulting radical intermediate6–17. Site-selectivity, however, remains a formidable challenge, especially among sp 3 C–H bonds with comparable properties. If the intermediate radical could be further trapped enantioselectively, this should enable highly site- and enantioselective functionalization of C–H bonds. Here we report a copper (Cu)-catalysed site- and enantioselective allylic C–H cyanation of complex alkenes, in which a Cu(ii)-bound nitrogen (N)-centred radical plays the key role in achieving precise site-specific HAT. This method is shown to be effective for a diverse collection of alkene-containing molecules, including sterically demanding structures and complex natural products and pharmaceuticals. A Cu-bound nitrogen-centred radical is used to control site-specific and enantioselective allylic C–H cyanations of molecules with synthetic and medicinal relevance, such as tri- and tetrasubstituted alkenes.

中文翻译：

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位点特异性烯丙基 C-H 键官能化与铜结合的 N 中心自由基

选择性 C-H 键功能化的方法为化学家提供了多功能且强大的合成工具箱，例如先导化合物的后期修饰，而无需冗长的从头合成 1-5。考虑到大量可用的 HAT 受体和生成的自由基中间体 6-17 可用的反应途径的多样性，通过氢原子转移 (HAT) 裂解 sp 3 C-H 键特别有用。然而，位点选择性仍然是一个巨大的挑战，尤其是在具有可比性质的 sp 3 C-H 键中。如果中间自由基可以进一步被对映选择性捕获，这应该能够实现 C-H 键的高度位点和对映选择性功能化。在这里，我们报告了复杂烯烃的铜 (Cu) 催化位点和对映选择性烯丙基 C-H 氰化，其中以 Cu(ii) 结合的氮 (N) 为中心的自由基在实现精确的位点特异性 HAT 中起着关键作用。这种方法被证明对各种含烯烃分子的集合有效，包括空间要求高的结构和复杂的天然产物和药物。Cu结合的以氮为中心的自由基用于控制具有合成和医学相关性的分子（例如三取代和四取代烯烃）的位点特异性和对映选择性烯丙基C-H氰化。