Flexible synthesis of phenanthrenes by PtCl2-catalyzed cycloisomerization reaction
Flexible synthesis of phenanthrenes by PtCl2-catalyzed cycloisomerization reaction
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DOI：
10.1021/jo025962y
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发表时间：
2002-08-23
影响因子：
3.6
通讯作者：
Mamane, V
中科院分区：
文献类型：
--
作者：
Fürstner, A;Mamane, V
当在甲苯中催化量的PtCl2、AuCl3、GaCl3或InCl3时，容易获得的联苯衍生物在其一个邻位含有炔基单元的情况下被转化为取代菲。这种6-内-地高位环化反应可能通过炔烃单元的初始a配位进行，随后得到的ETA(2)-金属络合物被相邻的芳环截留。该反应本质上是模块化的，允许有很大的结构变化，并允许在菲产物的任何位置(C-9除外)加入取代基。此外，该反应很容易应用于杂环系列，例如制备苯并吲哚、萘并噻吩类以及桥头氮杂环。
Readily available biphenyl derivatives containing an alkyne unit at one of their ortho positions are converted into substituted phenanthrenes upon exposure to catalytic amounts of either PtCl2, AuCl3, GaCl3, or InCl3 in toluene. This 6-endo-dig cyclization likely proceeds through initial a-coordination of the alkyne unit followed by interception of the resulting eta(2)-metal complex by the adjacent arene ring. The reaction is inherently modular, allowing for substantial structural variations and for the incorporation of substituents at any site of the phenanthrene product except C-9. Moreover, the reaction is readily applied to the heterocyclic series as exemplified by the preparation of benzoindoles, naphthothiophenes as well as bridgehead nitrogen heterocycles.