A metal-free, Brønsted acid-mediated cascade cyclization of 2-propynolphenols for efficient synthesis of various 4-thiocyanated 2H-chromenes is developed by using KSCN as the thiocyanated source. This reaction was characterized by readily prepared starting materials, bearing good functional group tolerance and excellent yields. Moreover, the obtained 4-thiocyanated 2H-chromenes could be further derivated to potential bioactive and pharmaceutical molecules.

中文翻译：

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通过TFA介导的2-丙炔酚酚的级联环化反应，实现无金属高效合成4-硫氰化2 H-苯甲基的方法

通过使用KSCN作为硫氰化源，开发了一种无金属的布朗斯台德酸介导的2-丙炔酚酚级联环化反应，可有效合成各种4-硫氰化2 H-色烯。该反应的特征在于容易制备的起始原料，具有良好的官能团耐受性和优异的产率。而且，所获得的4-硫氰化的2 H-色烯可以进一步衍生为潜在的生物活性和药物分子。