Studies of the formation of all-carbon quaternary centres, en route to lyngbyatoxin A. A comparison of phenyl and 7-substituted indole systems
作者:Janne E. Tønder、Masood Hosseini、Alex B. Ahrenst、David Tanner
DOI:10.1039/b401490a
日期:——
mediated allylic substitutions and conjugate additions to geranyl, cinnamyl and allylic indole compounds have been investigated with the aim of finding a method for the creation of the all-carbon quaternary centre present in the natural product lyngbyatoxin A. Reaction conditions have been found giving a 68% SN2' selectivity in the copper mediated addition of PhMgBr to geranyl chloride, as well as 99%
研究了铜介导的烯丙基取代和香叶基,肉桂基和烯丙基吲哚化合物的共轭加成反应,目的是寻找一种方法来创建天然产物lyngbyatoxin A中存在的全碳四元中心。铜介导的将PhMgBr添加到香叶酰氯中的68%SN2'选择性,以及铜催化的EtMgBr分别添加到肉桂酰氯和乙酸盐中的99%和95%SN2'选择性。当将优化的反应条件应用于相应的含有7个取代的吲哚部分的烯丙基化合物时,区域选择性相反,仅得到SN2产物。还发现含烯丙基吲哚的底物在Pd或Mo催化的SN2'中无效 型取代反应。在相关研究中,铜催化的EtMgBr到三环内酰胺6-甲基-吡咯并[3,2,1-ij]喹啉-4-酮的共轭加成反应最多可产生20%的1,4-加成产物。