Chai Jinkui, Ding Wei, Wang Chen, Ito Shingo, Wu Junliang, Yoshikai Naohiko
College of Chemistry, Institute of Green Catalysis, Zhengzhou University Zhengzhou 450001 P. R. China
Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University Singapore 637371 Singapore.
Chem Sci. 2021 Nov 4;12(45):15128-15133. doi: 10.1039/d1sc05240c. eCollection 2021 Nov 24.
The Ritter reaction, Brønsted- or Lewis acid-mediated amidation of alkene or alcohol with nitrile a carbocation, represents a classical method for the synthesis of tertiary amides. Although analogous reactions through a vinyl cation or a species alike may offer a route to enamide, an important synthetic building block as well as a common functionality in bioactive compounds, such transformations remain largely elusive. Herein, we report a Ritter-type -difunctionalization of alkynes with a trivalent iodine electrophile and nitrile, which affords β-iodanyl enamides in moderate to good yields. Mediated by benziodoxole triflate (BXT), the reaction proves applicable to a variety of internal alkynes as well as to various alkyl- and arylnitriles. The benziodoxole group in the product serves as a versatile handle for further transformations, thus allowing for the preparation of various tri- and tetrasubstituted enamides that are not readily accessible by other means.
里特反应，即布朗斯台德酸或路易斯酸介导的烯烃或醇与腈反应生成碳正离子，是合成叔酰胺的经典方法。尽管通过乙烯基正离子或类似物种的类似反应可能为烯酰胺提供一条合成途径，烯酰胺是一种重要的合成砌块以及生物活性化合物中的常见官能团，但这种转化在很大程度上仍然难以实现。在此，我们报道了一种用三价碘亲电试剂和腈对炔烃进行的里特型双官能化反应，该反应能以中等至良好的产率得到β-碘代烯酰胺。由三氟甲磺酸苯并碘唑（BXT）介导，该反应被证明适用于多种内炔以及各种烷基腈和芳基腈。产物中的苯并碘唑基团可作为进一步转化的通用基团，从而能够制备通过其他方法不易获得的各种三取代和四取代烯酰胺。
