In the pursuit of forging innovative electrosynthetic pathways and nurturing sustainable chemical processes, an in-depth comprehension of the structure and reactivity of reactive intermediates emerges as an imperative. However, the inherent challenges associated with the discernment and characterization of these transient entities arise from their meager concentrations and ephemeral nature. Herein, we present a cutting-edge floating electrolytic electrospray ionization (FE-ESI) strategy, enabling real-time monitoring and characterizing of short-lived intermediates within a floating electrolytic cell by high-resolution mass spectrometry (HRMS). Through the capture of radical cations and crucial intermediates, we acquired unambiguous evidence that sheds light on the inherent reaction process between indole radical cations and radical precursors, as well as nucleophilic reagents. This, in turn, guides the exploration of an electrochemical dearomatizative esterification of indole, culminating in the synthesis of a diverse array of 3,3-disubstituted oxindoles with notable regioselectivities.

在追求创新电合成途径和培育可持续化学过程的过程中，深入理解反应中间体的结构和反应性势在必行。然而，与这些瞬态实体的辨别和表征相关的固有挑战源于它们的浓度微薄和短暂的性质。在此，我们提出了一种尖端的浮动电解电喷雾电离（FE-ESI）策略，能够通过高分辨率质谱（HRMS）实时监测和表征浮动电解池内的短寿命中间体。通过捕获自由基阳离子和关键中间体，我们获得了明确的证据，揭示了吲哚自由基阳离子和自由基前体以及亲核试剂之间的固有反应过程。这反过来又指导了吲哚电化学脱芳构酯化的探索，最终合成了多种具有显着区域选择性的 3,3-二取代羟吲哚。