Cobalt-Catalyzed Formal [4+2] Cycloaddition of α,α′-Dichloro-<i>ortho</i>-Xylenes with Alkynes
作者:Kimihiro Komeyama、Yuji Okamoto、Ken Takaki
DOI:10.1002/anie.201406807
日期:2014.10.13
A formal [4+2] cycloaddition of α,α′‐dichloro‐ortho‐xylenes with various alkynes has been developed using a low‐valent cobalt catalyst. The transformation has a wide substrate scope and high functional‐group tolerance and led to 1,4‐dihydronaphthalenes. The formed cycloadducts were easily aromatized with MnO2 under air. A mechanistic investigation suggests that the transformation proceeds through a
使用低价钴催化剂开发了α,α′-二氯邻二甲苯与各种炔烃的正式[4 + 2]环加成反应。该转化具有广泛的底物范围和较高的官能团耐受性,并导致了1,4-二氢萘。形成的环加合物很容易在空气中被MnO 2芳香化。机理研究表明,该转化过程是通过炔烃的苄基钴化反应完成的,而不是邻喹啉二甲烷的经典Diels-Alder反应。这种方法为线性扩展的π共轭芳族化合物提供了一种简单,流线型的访问方法。