作者:Lior Eshdat、Harald Berger、Henning Hopf、Mordecai Rabinovitz
DOI:10.1021/ja0174074
日期:2002.4.1
Cross-conjugated enediynes cannot follow the Bergman cycloaromatization as it involves a methylenediyne moiety with only five pi e(-), insufficient for aromatization. Under reductive conditions the cyclization is made feasible by generating a product with a Hückel number of pi electrons. We illustrate this principle and demonstrate for the first time an anionic cyclization of a cross-conjugated enediyne that results
交叉共轭的烯二炔不能遵循伯格曼环芳构化,因为它涉及只有五个 pie(-) 的亚甲基二炔部分,不足以进行芳构化。在还原条件下,通过生成具有休克尔数 pi 电子的产物,使环化变得可行。我们说明了这一原理,并首次证明了交叉共轭烯二炔的阴离子环化导致形成五元环。9-(3-Phenyl-1-phenylethynylprop-2-ynylidene)-9H-芴 (3) 被钾还原得到 9-(3,4-diphenylcyclopenta-2,4-diylidene)-9H-芴的二价阴离子(4(2-)),其中包含一个环戊二烯基片段,用碘氧化产生不稳定的富瓦烯 4。