作者:DEFOIN, A.、AUGEIMANN, G.、FRITZ, H.、GEFFROY, G.、SCHMIDLIN, C.、STREITH, J.
DOI:——
日期:——
Controllable Cycloadditions between 2<i>H</i>-(Thio)pyran-2-(thi)ones and Strained Alkynes: A Click-and-Release Strategy for COS/H<sub>2</sub>S Generation
作者:Qi Cui、Tony W. Pan、Meg Shieh、Shane S. Kelly、Shi Xu、Wei-Jun Qian、Ming Xian
DOI:10.1021/acs.orglett.2c02819
日期:2022.10.14
Cycloaddition of 2H-Pyran-2-thiones with Nitroso Derivatives. An Unexpected Cycloaddition-Rearrangement Reaction
Reaction of pyran-2-thiones 4 with nitrosoderivatives led surprisingly to type-8 (19) adducts which proved to be isomeric with the initially expected primary Diels-Alder cycloadducts 5. Methyl 2-thioxo-2H-pyran-5-carboxylate (4f), when reacted with nitrosobenzene at -10°, led quantitatively to the thieto-oxazine intermediate 13, which turned out to be the cornerstone of the complex cycloaddition-rearrangement
吡喃-2-硫酮的反应4与导致令人惊奇的亚硝基衍生物型- 8(19被证明是同分异构体与最初的预期主要)加合物狄尔斯-阿尔德cycloadducts 5。当在-10°下与亚硝基苯反应时,2-thioxo-2 H -pyran-5-羧酸甲酯(4f)定量地导致硫代恶嗪中间体13转化为复杂的环加成重排5 的基石。8个反应途径(方案3)。差示扫描量热法,与18a 19a相同转化,被允许证明该多步重排总体上是高温放热过程,最终产物19代表沿着该反应路径的能量吸收器。