We present a silver‐catalyzed reaction of acceptor‐enynals with alkynes to assemble tetracyclic framework of fluorenols efficiently, in which the reaction was proposed to proceed through an unfavorable 6‐endo‐dig cyclization, followed by a tandem [4+2] cycloaddition/Friedel–Crafts reaction. The reaction could be conducted in one pot for diaryl alkynes substrates. For terminal aryl alkyne or arylalkyl alkyne substrates, the Friedel–Crafts reaction has to be performed in the absence of alkynes. The control reactions demonstrated that there was competition between [Ag]⋅⋅⋅alkyne and [Ag]⋅⋅⋅O=CR₂.

中文翻译：

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通过不利于6-endo-dig环化的受体-烯类和炔烃的银催化串联反应，可高效组装四环芴醇

我们提出了一种炔烃与炔烃的银催化反应，以有效地组装芴的四环骨架，其中该反应被提议通过不利的6 -endo-dig环化反应，然后进行串联[4 + 2]环加成反应/ Friedel-Crafts反应。对于二芳基炔烃底物，该反应可以在一个罐中进行。对于末端芳基炔烃或芳基烷基炔烃底物，必须在不存在炔烃的条件下进行Friedel-Crafts反应。对照反应表明，[Ag]···⋅炔烃与[Ag]···⋅O= CR ₂之间存在竞争。