DOI: 10.1002/adsc.202300685 ISSN:
Expanding the Potential of 3‐Hydroxyindolinones:Synthesis of Quinoxalin‐2(1H)‐ones through Acid‐Promoted Azidation and Ring‐Expansion
Shuming Zhan, Heng Xu, Lin Li, Wenjing Guo, Biqiong Hong, Zhenhua Gu- General Chemistry
We report herein a synthesis of quinoxalin‐2(1<i>H</i>)‐ones from 3‐hydroxyindolin‐2‐one derivatives, which can be synthesized from commercially available isatins in one or two steps. The reaction proceeded through a CF<sub>3</sub>CO<sub>2</sub>H‐mediated azidation via a carbocation, followed by acid‐induced N<sub>2</sub> extrusion and ring‐expansion. Both CF<sub>3</sub>CO<sub>2</sub>H and the solvent 1,1,1,3,3,3‐hexafluoro‐2‐propanol were found to be crucial for this rearrangement. The axial chirality in 3‐hydroxyindolin‐2‐one skeleton was fully preserved in the products.