Functional Group Translocation of Cyano Groups by Reversible C-H Sampling.

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 C-H bond. The reaction shows high fidelity for 1,4-CN translocation, frequently contrary to inherent site selectivity in conventional C-H 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.