Synthesis of the CD-ring of the anticancer agent streptonigrin: studies of aryl–aryl coupling methodologies
作者:William T. McElroy、Philip DeShong
DOI:10.1016/j.tet.2006.04.074
日期:2006.7
the success of the coupling process. Analogs of the CD biaryl were prepared by coupling of aryl siloxane derivatives (D-ring component) with highly functionalized 4-bromopyridines (C-ring); however, the CD biaryl of the natural product could not be prepared in high yield by siloxane coupling due to the facile formation of reduced pyridine under the coupling conditions. Alternatively, the fully functionalized
制备了一系列代表抗癌药链霉菌素C环的功能化4-溴吡啶,并评估了它们与链霉菌素D环硅氧烷进行Pd催化交叉偶联的能力。偶联反应通常耐受受阻CD联芳基的制备。然而,双方的电子效应在耦合过程的成功中起着举足轻重的作用。CD联芳基的类似物是通过将芳基硅氧烷衍生物(D-环组分)与高度官能化的4-溴吡啶(C-环)偶联而制得的。然而,由于在偶联条件下容易形成还原的吡啶,因此不能通过硅氧烷偶联以高产率制备天然产物的CD联芳基。或者,用适当官能化的C-环溴化物和D-环芳基硼酸的Suzuki偶联制备链霉菌素的完全官能化的CD联芳基。所描述的方法是高度收敛的并且容易适用于类似物的合成。