Since oxazoles have found widespread applications not only as synthetic intermediates but also as biologically active compounds, much effort has been focused on developing novel and efficient methods for the synthesis of this heterocycle. From the viewpoint of green and sustainable chemistry, hypervalent iodine and other halogen reagents have gained increasing popularity in metal-free oxidative transformation due to their low toxicity, transition-metal-like reactivity, high stability, easy handling and other benefits. In this account, our two approaches to the metal-free synthesis of oxazoles by means of a peculiar activation of alkynes by iodine species are described with the related contexts. One is iodine(III)-mediated/catalyzed oxidative cycloisomerization reactions of N-propargyl amides for the preparation of oxazoles bearing various functional groups at their side chains. In these reactions, iodine(III) species works as a donor of various heteroatomic functional groups as well as an activator of carbon-carbon triple bonds in a single step. Furthermore, this methodology can be extended to iodine(III)-mediated/catalyzed oxidative annulation of alkynes and nitriles as another approach, in which heteroatoms on iodine(III) species are incorporated in the azole rings.

由于恶唑不仅作为合成中间体而且作为生物活性化合物都得到了广泛的应用，因此人们已经集中精力开发新颖而有效的方法来合成该杂环。从绿色和可持续化学的观点来看，高价碘和其他卤素试剂因其低毒性，类过渡金属反应性，高稳定性，易于处理等优点而在无金属的氧化转化中越来越受欢迎。因此，在相关的上下文中描述了我们的两种通过碘物种对炔烃进行特殊活化而无金属合成恶唑的方法。一种是碘（III）介导的/ N-炔丙基酰胺的催化氧化环异构化反应，用于制备侧链带有各种官能团的恶唑。在这些反应中，碘（III）物种可在一个步骤中充当各种杂原子官能团的供体以及碳-碳三键的活化剂。此外，作为另一种方法，该方法可以扩展到炔烃和腈的碘（III）介导的/催化的氧化环化反应中，其中碘（III）物种上的杂原子掺入到唑环中。