Gold(I)-Catalyzed Intramolecular [4+2] Cycloadditions of Arylalkynes or 1,3-Enynes with Alkenes: Scope and Mechanism
作者:Cristina Nieto-Oberhuber、Patricia Pérez-Galán、Elena Herrero-Gómez、Thorsten Lauterbach、Cristina Rodríguez、Salomé López、Christophe Bour、Antonio Rosellón、Diego J. Cárdenas、Antonio M. Echavarren
DOI:10.1021/ja075794x
日期:2008.1.1
The cyclizations of enynes substituted at the alkyne gives products of formal [4+2] cyclization with Au(I) catalysts. 1,8-Dien-3-ynes cyclize by a 5-exo-dig pathway to form hydrindanes. 1,6-Enynes with an aryl ring at the alkyne give 2,3,9,9a-tetrahydro-1H-cyclopenta[b]naphthalenes by a 5-exo-dig cyclization followed by a Friedel-Crafts-type ring expansion. A 6-endo-dig cyclization is also observed
在炔烃上取代的烯炔环化得到正式的 [4+2] 环化产物与 Au(I) 催化剂。1,8-Dien-3-ynes 通过 5-exo-dig 途径环化形成hydrindanes。在炔烃上带有芳环的 1,6-烯炔通过 5-exo-dig 环化和 Friedel-Crafts 型环扩展得到 2,3,9,9a-四氢-1H-环戊 [b] 萘。在某些情况下,6-endo-dig 环化也被视为次要过程,尽管在少数情况下,这是主要的环化途径。除了带有大量联苯膦的阳离子金配合物外,具有三(2,6-二叔丁基苯基)亚磷酸酯的金配合物作为该反应的催化剂具有异常的反应活性。在微波辐射下加热也可以非常有效地进行这种环化。