Liu Feng, Ma Dawei
State Key Laboratory of Bioorganic and Natural Products Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 354 Fenglin Lu, Shanghai 200032, China.
J Org Chem. 2007 Jun 22;72(13):4844-50. doi: 10.1021/jo070547x. Epub 2007 May 27.
Cross-coupling of 1-alkynes with vinyl iodides occurs at 80 degrees C in dioxane catalyzed by CuI/N,N-dimethylglycine to afford conjugated enynes in good to excellent yields. Heating a mixture of 2-bromotrifluoroacetanilide, 1-alkyne, 2 mol % of CuI, 6 mol % of L-proline, and K(2)CO(3) in DMF at 80 degrees C leads to the formation of the corresponding indole. This conversion involves a CuI/L-proline-catalyzed coupling between aryl bromide and the 1-alkyne followed by a CuI-mediated cyclization process. An ortho-substituent effect directed by NHCOCF3 enables the reaction to proceed under these mild conditions. Both aryl acetylenes and O-protected propargyl alcohol can be applied, leading to 5-, 6-, or 7-substituted 2-aryl and protected 2-hydroxymethyl indoles in good yields. With simple aliphatic alkynes, however, lower yields were observed.
1-炔烃与乙烯基碘化物的交叉偶联反应在80℃的二氧六环中，以碘化亚铜/N,N-二甲基甘氨酸为催化剂进行，可得到产率良好至优异的共轭烯炔。将2-溴三氟乙酰苯胺、1-炔烃、2摩尔%的碘化亚铜、6摩尔%的L-脯氨酸和碳酸钾在N,N-二甲基甲酰胺中于80℃加热，会生成相应的吲哚。该转化过程涉及碘化亚铜/L-脯氨酸催化的芳基溴与1-炔烃之间的偶联反应，随后是碘化亚铜介导的环化过程。由NHCOCF3引导的邻位取代基效应使反应能够在这些温和条件下进行。芳基乙炔和O-保护的炔丙醇均可应用，能以良好的产率得到5-、6-或7-取代的2-芳基吲哚以及保护的2-羟甲基吲哚。然而，对于简单的脂肪族炔烃，产率较低。
