We report a unique synthetic route to benzo[7]annulene derivatives. When benzylidene malonates having a 1-(N,N-dialkylamino)alkyl group at the ortho-position are treated with a stoichiometric amount of M(OTf)₃ (M = Sc, Yb, Gd), three transformations ([1,4]-hydride shift/isomerization into an enamine/intramolecular Stork enamine acylation) proceed sequentially to afford various benzo[7]annulene derivatives in moderate chemical yields. To our knowledge, the present reaction is the first example of an internal redox reaction involving a [1,n]-hydride shift/(n+3)-cyclization process.

中文翻译：

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通过[1,4]-氢化物位移形成苯并[7]轮烯衍生物的(n+3)-环化：一种涉及内部氧化还原反应的新型环化模式

我们报告了苯并[7]轮烯衍生物的独特合成路线。当在邻位具有1-( N , N-二烷基氨基)烷基的亚苄基丙二酸酯用化学计量的M(OTf) ₃ (M=Sc,Yb,Gd)处理时，三个转化([1,4 ]-氢化物转移/异构化为烯胺/分子内Stork烯胺酰化）依次进行，以中等化学产率提供各种苯并[7]轮烯衍生物。据我们所知，本反应是涉及[1, n ]-氢化物移位/( n +3)-环化过程的内部氧化还原反应的第一个例子。