Beijing National Laboratory for Molecular Sciences, Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education, College of Chemistry, Peking University, Beijing 100871, PR China.
Chemistry. 2011 Feb 18;17(8):2442-9. doi: 10.1002/chem.201003119. Epub 2011 Jan 24.
5-Azaindoles either with three different substituents at their 2-, 4-, and 6-positions or with two identical substituents at their 2- and 6-positions and a different one at the 4-position, were obtained in good to excellent isolated yields by a zirconocene-mediated multicomponent process. Each reaction involved four organic partners, comprising a Si-tethered diyne, one tBuCN component, and two (either different or identical) nitriles. All these four components were combined through the action of a Cp(2)Zr(II) species into a three-ring fused Zr/Si-containing organometallic complex in a perfectly chemo- and regioselective manner. This multicomponent reaction process consisted of three reaction steps, all of which were made clear through the isolation and characterization of their corresponding organometallic intermediates: the zirconacyclopropene-azasilacyclopentadienes 2, the allenyl-aza-zirconacycles 3, and the three-ring fused complexes 6. X-ray single-crystal structural analyses of two three-ring fused Zr/Si-containing intermediates and two 5-azaindoles unambiguously showed the positions of the different substituents and the regioselectivity. Iminopyrrole derivatives could be also highly selectively prepared from a Si-tethered diyne and two different nitriles.
5-氮杂吲哚的 2-、4-和 6-位有三个不同取代基，或者 2-和 6-位有两个相同取代基，4-位有一个不同取代基，通过锆介导的多组分反应以良好到优异的分离产率得到。每个反应涉及四个有机伙伴，包括一个 Si 键合二炔、一个 tBuCN 组分和两个（不同或相同）腈。所有这四个组件都通过 Cp(2)Zr(II) 物种的作用组合成一个三环融合的 Zr/Si 含金属有机配合物，具有完美的化学和区域选择性。该多组分反应过程由三个反应步骤组成，通过对相应的金属有机中间体的分离和表征，都清楚地说明了这一点：锆环丙烯-氮杂硅环戊二烯 2、烯丙基-氮杂锆环 3 和三环融合的配合物 6。两个三环融合的 Zr/Si 含中间体和两个 5-氮杂吲哚的 X 射线单晶结构分析明确显示了不同取代基的位置和区域选择性。从 Si 键合二炔和两个不同的腈也可以高度选择性地制备亚氨基吡咯衍生物。
