Ethoxyvinyllithium-HMPA. Surprising Regiochemistry in Aromatic Metalation
Ethoxyvinyllithium-HMPA. Surprising Regiochemistry in Aromatic Metalation
复制标题
乙氧基乙烯基锂-HMPA。
DOI：
10.1021/ja00102a069
复制
发表时间：
1994
影响因子：
15
通讯作者：
A. Meyers
中科院分区：
文献类型：
--
作者：
M. Shimano;A. Meyers
“生成芳基锂的总时间。除非另有说明，所有的金属化都是在78℃下进行的。c比值由粗产物混合物的H-NMR （300 MHz, CDCI3）测定。加入多聚甲醛后，将混合物加热至环境温度。标准的芳族金属化与普通锂碱的反应很少涉及不同的动力学和热力学区域化学。虽然尚未得到证实，但锂取代基从动力学位置到热力学位置的重排很可能是一个双分子过程。在另一项实验中，简要地评估了甲氧基与通常更强的定向组的相对效率，6a
“Total time to generate aryllithium. Unless otherwise noted, all metalations were carried out at—78 C. b All yields were for isolated, purified products. c Ratios were determined by ‘H-NMR (300 MHz, CDCI3) of the crudeproduct mixture. d Metalation performed at—83 Ce After paraformaldehyde was added, the mixture was warmed to ambient temperature. the standard aromatic metalation with common lithio bases has rarely been shown to involve different kinetic and thermodynamic regiochemistry. 12 Although yet to be confirmed, the rearrangement of the lithio substituent from the kinetic to the thermodynamic position is very likely a bimolecular process. 13 In another experiment to briefly assess the relative efficiency of the methoxyl vs the normally stronger directing group, 6a