Lewis acid-catalyzed [4+2] benzannulation between enynal units and enols or enol ethers: Novel synthetic tools for polysubstituted aromatic compounds including indole and benzofuran derivatives
Lewis acid-catalyzed [4+2] benzannulation between enynal units and enols or enol ethers: Novel synthetic tools for polysubstituted aromatic compounds including indole and benzofuran derivatives
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DOI：
10.1021/jo060597m
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发表时间：
2006-07-07
影响因子：
3.6
通讯作者：
Aikawa, Haruo
中科院分区：
文献类型：
--
作者：
Asao, Naoki;Aikawa, Haruo
[图解]烯醛1，包括邻炔基苯甲醛，与羰基化合物2，如醛和酮，在100℃下，在1，4-二氧六环中催化量AuBr3的存在下，高产率地得到官能化的芳香化合物3。类似地，AuBr3催化的1与缩醛化合物5的反应以良好的产率得到相应的芳香化合物3。另一方面，当100℃时，在Cu2(NTF2)(2)和1当量H2O(CH2Cl2)的催化下，反应在3上选择性地得到脱羰基萘产物4。使用本苯环方法还合成了苯并二氢杂环化合物，如吲哚衍生物13和苯并呋喃衍生物15。
[GRAPHICS]The reaction of enynals 1, including o-(alkynyl) benzaldehydes, and carbonyl compounds 2, such as aldehydes and ketones, in the presence of a catalytic amount of AuBr3 in 1,4-dioxane at 100 degrees C gave the functionalized aromatic compounds 3 in high yields. Similarly, the AuBr3-catalyzed reactions of 1 with acetal compounds 5 afforded the corresponding aromatic compounds 3 in good yields. On the other hand, when the reaction was carried out in the presence of a catalytic amount of Cu(NTf2)(2) and 1 equiv of H2O in (CH2Cl)(2) at 100 degrees C, the decarbonylated naphthalene products 4 were obtained selectively over 3. Benzofused heteroaromatic compounds, such as indole derivatives 13 and benzofuran derivatives 15, were also synthesized by using the present benzannulation methodology.