Here, we report the first divergent synthesis of benzo-fused O-heterocycles by p-toluene sulfonic acid promoted cascade reactions involving alkyne hydration, double cyclization, ring contraction and C–O bond cleavage from alkynols. The reaction mechanism was validated by obtaining the X-ray structure of fused benzo[b]oxepine intermediates. Moreover, some of the obtained derivatives could be transformed into 2,3-disubstituted naphthoquinones as important structural motifs in natural products and bioactive molecules.

中文翻译：

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p -TsOH通过环收缩和C–O断裂策略促进了炔烃合成苯并稠合的O-杂环

在这里，我们报道了由对甲苯磺酸促进苯并稠合的O杂环的首次发散合成，该反应促进了级联反应，涉及炔烃水合，双环化，环收缩和炔醇裂解C-O键。通过获得熔融的苯并[ b ]氧杂环庚烷中间体的X射线结构来验证反应机理。而且，一些获得的衍生物可以转化为2，3-二取代的萘醌，作为天然产物和生物活性分子中的重要结构基序。