A novel, efficient and metal-free cascade sulfonylation/cyclization of 2-propynolphenols with commercially available sodium sulfinates was developed for the synthesis of 4-sulfonyl 2H-chromenes under mild conditions. The reaction occurred by the sodium sulfinates’ nucleophilic addition of the allylene carbocation intermediate followed by a 6-endo-trig pathway. Additionally, this approach avoids the use of an oxidant or a photo-radical inducer and the reaction can tolerate a wide variety of functional groups in good yields.

中文翻译：

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在无金属的条件下， TFA促进的2-丙炔酚与亚磺酸钠的磺化/级联环化成4-磺酰基2 H-色烯†

开发了一种新颖，有效且无金属的2-丙炔酚与市售亚磺酸钠的级联磺酰化/环化反应，用于在温和条件下合成4-磺酰基2 H-苯甲基。该反应是通过亚磺酸钠的亚烷基碳阳离子中间体的亲核加成，然后是6-内-trig途径而发生的。另外，该方法避免了使用氧化剂或光自由基诱导剂，并且该反应可以良好的产率耐受多种官能团。