Biaryl ethers condense directly with carbonyl groups on diazafluorenones, acenaphthenequinone, and isatins, to give a variety of spirocyclic compounds. The condensation reactions are promoted by the Brønsted superacid, CF₃SO₃H (triflic acid). This methodology provides a convenient one-pot synthetic route to aromatic spirocycles.

中文翻译：

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与联芳基醚和羰基缩合形成螺环

联芳基醚直接与二氮杂芴酮、苊醌和靛红上的羰基缩合，得到多种螺环化合物。_{Brønsted 超强酸 CF 3} SO ₃ H（三氟甲磺酸）可促进缩合反应。该方法为芳香螺环化合物提供了一条方便的一锅法合成路线。