Photo-Promoted Construction of 3‑Spiro-2-sulfonylimino-indoline Skeletons via Cascade Reaction

The cascade reaction of 3-diazo-2-sulfonyliminoindolines and N-methoxymethyl-N-[(trimethylsilyl)methyl]benzylamines generates 2-sulfonylimino-1′,3′,4′,6′-tetrahydro-2’H-spiro[indoline-3,5′-pyrimidine] and spiro[indoline-3,3′-pyrrolidine] derivatives simultaneously under the catalysis of TFA and blue light irradiation. Their formation mechanisms were proposed on the basis of isotope-labeled experiments and HRMS analysis of the controlled experiment mixture, showing new reaction pathways. The current reaction provides a new strategy for the synthesis of biologically important spiro[indoline-3,3′-pyrrolidine]-2-one derivatives.

在三氟乙酸（TFA）催化并蓝光照射的条件下，3-重氮-2-磺酰亚胺基吲哚啉（3-diazo-2-sulfonyliminoindolines）与N-甲氧基甲基-N-[(三甲基硅基)甲基]苄胺发生级联反应，可同时生成2-磺酰亚胺基-1′,3′,4′,6′-四氢-2’H-螺[吲哚啉-3,5′-嘧啶]与螺[吲哚啉-3,3′-吡咯烷]类衍生物。研究人员基于同位素标记实验与对照反应混合物的高分辨质谱（HRMS）分析，提出了该反应的生成机理，揭示了全新的反应路径。本反应为具有重要生物活性的螺[吲哚啉-3,3′-吡咯烷]-2-酮类衍生物的合成提供了新策略。