北京大学许言团队报道了用可逆C–H采样实现氰基的官能团易位。相关研究成果于2023年6月26日发表在《自然》。

引入、去除或操纵官能团（FGs）的化学转化在合成化学中普遍存在。与将一种官能团交换为另一种官能团的传统FG相互转化反应不同，仅改变FGs位置的转化很少被探索。

该文中，通过光催化、可逆的C–H采样，研究人员报道了常见腈中氰基（CN）基团的FG易位反应，使CN和未活化的CH键之间的直接位置交换。该反应显示出1,4-CN易位的高保真度，这通常与传统CH官能化中固有的位点选择性相反。研究人员还报道了环状系统的直接跨环CN易位，提供了通过其他方法获得的有价值结构的途径。

利用CN的合成多功能性和关键的CN易位步骤，研究人员展示了生物活性分子构建块的简明合成。此外，C–H氰化和CN易位的结合能获得非常规的C–H衍生物。

总的来说，所报道的反应代表了一种实现位点选择性C–H转化反应的方法，而不需要位点选择性的C–H切割步骤。

附：英文原文

Title: Functional Group Translocation of Cyano Groups by Reversible C–H Sampling

Author: Chen, Ken, Zeng, Qingrui, Xie, Longhuan, Xue, Zisheng, Wang, Jianbo, Xu, Yan

Issue&Volume: 2023-06-26

Abstract: Chemical transformations that introduce, remove, or manipulate functional groups (FGs) are ubiquitous in synthetic chemistry.1 Unlike conventional FG interconversion reactions that swap one functionality for another, transformations that alter solely the location of FGs are far less explored. Here, by photocatalytic, reversible C–H sampling, we report a FG translocation reaction of cyano (CN) groups in common nitriles, allowing for the direct positional exchange between a CN and an unactivated CH bond. The reaction shows high fidelity for 1,4-CN translocation, frequently contrary to inherent site selectivity in conventional CH functionalizations. We also report the direct transannular CN translocation of cyclic systems, providing access to valuable structures that are non-trivial to obtain by other methods. Making use of the synthetic versatility of CN and a key CN translocation step, we showcase concise syntheses of building blocks of bioactive molecules. Furthermore, the combination of C–H cyanation and CN translocation allows access to unconventional C–H derivatives. Overall, the reported reaction represents a way to achieve site-selective C–H transformation reactions without requiring a site-selective C–H cleavage step.

DOI: 10.1038/s41586-023-06347-3

Source: https://www.nature.com/articles/s41586-023-06347-3