Abstract Evidence was collected for the intermediate formation of thionium ions in Brønsted acid-catalyzed [2 + 2] photocycloaddition and electrophilic addition reactions to enone dithianes and dithiolanes. Low-temperature NMR studies helped to elucidate the structure and configuration of the thionium ions and thus support previous and current results obtained by UV/Vis spectroscopy. Graphical Abstract

中文翻译：

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α-硫代碳阳离子（硫鎓离子）作为烯酮衍生的 1,3-二硫杂环戊烷和 1,3-二硫杂环戊烷的布朗斯台德酸催化反应的中间体。

摘要 收集了在 Brønsted 酸催化的 [2 + 2] 光环加成反应和烯酮二硫杂环戊烷和二硫杂环戊烷的亲电加成反应中形成硫鎓离子的证据。低温核磁共振研究有助于阐明硫鎓离子的结构和构型，从而支持通过紫外/可见光谱获得的先前和当前结果。图形概要