A Synthesis of Conjugatively Bridged Bis- and Tris-5-(2,2‘-Bipyridines): Multitopic Metal Ion-Binding Modules for Supramolecular Nanoengineering
作者:P. N. W. Baxter
DOI:10.1021/jo990665n
日期:2000.3.1
(5d,e) to ensure completion of the Stille cross-coupling reactions. The Stille cross-couplings showed a marked substituent effect in which the terminally phenylated bis- and tris-5-(2,2'-bipyridines) were formed in higher yields than the methyl-substituted analogues with the same bridge. The advantages of the methodology lie in its synthetic convenience and adaptibility for creating multitopic metal
提出了具有刚性共轭桥的纳米级的线性和弯曲的双和支链的tris-5-(2,2'-联吡啶)的高效制备方法。该合成避免了保护/脱保护方法的需要,它利用通过化学选择性钯催化的Sonogashira或Negishi交叉偶联方案与5-(2-氯吡啶)合子向外双-和三官能化的中心桥前体来产生桥连的线性(5a-c,5f,g)和弯曲的(6,7)双和支链(8)tris-5-(2-chloropyridines)。在更强的条件下,乙炔桥接的5-(2-氯吡啶)与2-三甲基苯乙烯基吡啶进行Stille交叉偶联反应,得到共轭桥接的线性(1a,b,1g-j)和弯曲的(2a,b,3a ,b)双分支和分支,(4a,b)tris-5-(2,2' -联吡啶),总收率良好。最好由双-5-(2-溴吡啶)(5d,e)制备苯基和联苯桥连的线性双-5-(2,2'-联吡啶)(1c-f),以确保斯蒂勒(Stille)的完成交叉偶联反应。斯蒂勒