Thiazoles and isothiazoles are privileged motifs in drug and agrochemical discovery.^1,2 The synthesis of these derivatives is generally approached, designed and developed on a case-by-case basis. Sometimes, the lack of robust synthetic methods to a given target can pose significant difficulties or even thwart the preparation of specific derivatives for further study.^3,4 Here, we report a conceptually different approach whereby photochemical irradiation can be used to alter the structure of thiazoles and isothiazoles in a selective and predictable manner. Upon photoexcitation, these derivatives populate their π,π* singlet states that undergo a series of structural rearrangements leading to an overall permutation of the cyclic system and its substituents. This means that once the initial heteroaromatic scaffold has been prepared, it can then function as an entry point to access other molecules by selective structural permutation. This approach operates under mild photochemical conditions which tolerate complex scaffolds and chemically distinct functionalities. Preliminary findings also indicate the potential for extending this method to other azole systems, including benzo[d]isothiazole, indazole, pyrazole and isoxazole. This strategy establishes photochemical permutation as a powerful and convenient method for the preparation of complex and difficult-to-access derivatives from more available structural isomers.

噻唑类和异噻唑类是药物和农用化学品发现中的特权基序。^1,2 这些衍生物的综合通常是根据具体情况进行处理、设计和开发的。有时，缺乏针对给定靶标的稳健合成方法可能会带来重大困难，甚至阻碍制备特定衍生物以供进一步研究。^3,4 在这里，我们报告了一种概念上不同的方法，其中光化学照射可用于以选择性和可预测的方式改变噻唑类和异噻唑类的结构。在光激发时，这些衍生物填充了它们的 π，π* 单重态，这些单重态经历了一系列结构重排，导致环系及其取代基的整体排列。这意味着，一旦初始杂芳烃支架准备好，它就可以作为通过选择性结构排列进入其他分子的入口点。这种方法在温和的光化学条件下运行，可耐受复杂的支架和化学上不同的功能。初步研究结果还表明，该方法有可能扩展到其他唑类系统，包括苯并[d]异噻唑、吲吲唑、吡唑和异恶唑。该策略将光化学排列确立为一种强大而方便的方法，用于从更可用的结构异构体制备复杂且难以获得的衍生物。