The Photochemical Mediated Ring Contraction of 4<i>H</i>-1,2,6-Thiadiazines To Afford 1,2,5-Thiadiazol-3(2<i>H</i>)-one 1-Oxides
作者:Emmanouil Broumidis、Christopher G. Thomson、Brendan Gallagher、Lia Sotorríos、Kenneth G. McKendrick、Stuart A. Macgregor、Martin J. Paterson、Janet E. Lovett、Gareth O. Lloyd、Georgina M. Rosair、Andreas S. Kalogirou、Panayiotis A. Koutentis、Filipe Vilela
DOI:10.1021/acs.orglett.3c02673
日期:2023.9.22
1,2,6-Thiadiazines treated with visible light and 3O2 under ambient conditions are converted into difficult-to-access 1,2,5-thiadiazole 1-oxides (35 examples, yields of 39–100%). Experimental and theoretical studies reveal that 1,2,6-thiadiazines act as triplet photosensitizers that produce 1O2 and then undergo a chemoselective [3 + 2] cycloaddition to give an endoperoxide that ring contracts with
在环境条件下用可见光和3 O 2处理的 1,2,6-噻二嗪转化为难以获得的 1,2,5-噻二唑 1-氧化物(35 个例子,产率 39-100%)。实验和理论研究表明,1,2,6-噻二嗪作为三线态光敏剂,产生1 O 2,然后进行化学选择性 [3 + 2] 环加成,得到内过氧化物,该内过氧化物通过选择性碳原子切除和完整的原子经济而收缩。该反应在间歇和连续流动条件下进行了优化,并且在绿色溶剂中也很有效。