REGIOSELECTIVE METALATION REACTIONS OF SOME SUBSTITUTED (METHOXYMETHOXY)ARENES
REGIOSELECTIVE METALATION REACTIONS OF SOME SUBSTITUTED (METHOXYMETHOXY)ARENES
复制标题
DOI：
10.1021/jo00132a022
复制
发表时间：
1982-01-01
影响因子：
3.6
通讯作者：
RONALD, RC
中科院分区：
文献类型：
--
作者：
WINKLE, MR;RONALD, RC
在氢-金属交换反应中，甲氧基甲氧基是一个相对较强的邻位导向基团。然而，导向效果受到金属化介质的影响，因此允许对金属化地点进行异常程度的控制。结合弱邻位导向基团，通过控制金属化溶剂的给电子量，可以将金属化邻位反应导向甲氧基甲氧基的任一邻位。在强给电子的溶剂中，1，2，4-取代模式由间位取代的甲氧基芳烃产生，而在非给电子的溶剂中，1，2，3-取代模式更受青睐。此外，甲氧基甲氧基还起到提高金属化速度和稳定芳基金属化产物的作用，从而抑制了一些竞争加成反应。
The methoxymethoxy substituent acts as a relatively strong ortho-directing group in hydrogen-metal exchange reactions. However, the directing effects are influenced by the metalation medium, thus permitting an unusual degree of control of the site of metalation. In conjunction with weak ortho-directing groups, the metalation ortho to the methoxymethoxy group can be directed to either of the ortho positions by controlling the electron-donating capacity of the metalating solvent. In strongly donating solvents the 1, 2, 4-substitution pattern will arise from a meta-substituted methoxymethoxy arene, while in nondonating solvents the 1, 2, 3-substitution is favored. In addition, the methoxymethoxy group serves also to enhance the rate of metalation and to stabilize the aryl-metalated products so that some competing addition reactions are suppressed.