Synthesis of 2-Substituted Cyclopenta[c]chromene Derivatives by α-C Insertion of Acetonitrile (Acetone)

Abstract

The efficient synthesis of 2-substituted cyclopenta[c]chromene derivatives was realized by α-C insertion of acetonitrile (acetone) with oxygen-linked 1,7-enynes catalyzed by cuprous bromide. The advantages of this reaction were wide range of substrates, high compatiblity of functional groups and good yield. The results showed that this was a radical reaction process, and it was also an effective way to construct oxygen-containing heterocycles. The X-ray diffraction analysis of 1-(4-fluorophenyl)-3a,8-dimethyl-2,3,3a,4-tetrahydrocyclopenta[c]chromene-2-carbonitrile (3am) further confirmed the structure of the product. Keywords radical reaction; oxygen-linked 1,7-enyne; chromene; CuBr 色烯是一类重要的含氧杂环化合物, 其骨架广泛存 在于天然产物和具有生物活性的药物分子中, 也是合成 产物的重要母核结构. 研究表明, 这类化合物具有很多 重要的生物活性, 如抗菌 12] 以取代水杨醛、 丙二腈和取 代 2-巯基咪唑的多组分反应合成了色烯衍生物. 经过考 察可以发现, 这些已报道色烯衍生物的合成方法多为常 规条件下反应, 且反应试剂和反应类型基本相似. 因此, 开发新的反应底物和新的反应方式构建色烯结构的化 合物依然具有合成意义.