Site-selective direct arylation of unprotected adenine nucleosides mediated by palladium and copper: insights into the reaction mechanism
作者:Thomas E. Storr、Andrew G. Firth、Karen Wilson、Kate Darley、Christoph G. Baumann、Ian J.S. Fairlamb
DOI:10.1016/j.tet.2008.01.062
日期:2008.6
Reaction conditions facilitating the site-selective direct aryl functionalisation at the C-8 position of adenine nucleosides have been identified. Many different aromatic components may be effectively cross-coupled to provide a diverse array of arylated adenine nucleoside products without the need for ribose or adenine protecting groups. The optimal palladium catalyst loading lies between 0.5 and 5 mol %
已经确定了促进在腺嘌呤核苷的C-8位上的位点选择性直接芳基官能化的反应条件。许多不同的芳族成分可以有效地交叉偶联,以提供多种阵列的芳基化腺嘌呤核苷产物,而无需核糖或腺嘌呤保护基。钯催化剂的最佳负载量为0.5至5mol%。向反应中添加过量的汞对催化的影响可忽略不计,表明均质催化物质的参与。透射电子显微镜(TEM)的研究表明,含金属的纳米粒子约占 在反应的后面阶段形成具有良好均匀性的3nm。稳定的PVP钯胶体(PVP = N-聚乙烯吡咯烷酮)在直接芳基化过程中具有催化活性,将均相钯释放到溶液中。已经研究了各种取代的2-吡啶配体添加剂的作用。提出了一种腺苷的位点选择性芳构化的机制。