Promoting or Preventing Haloaryllithium Isomerizations: Differential Basicities and Solvent Effects as the Crucial Variables
作者:Manfred Schlosser、Christophe Heiss、Thierry Rausis
DOI:10.1055/s-2005-861787
日期:——
Deprotonation-triggered heavy halogen migrations should become a favorite tool in arene synthesis if their occurrence and outcome could be made predictable. Particularly attractive, though extremely rare, are stop-and-go situations where a first intermediate, generated by metalation, can be trapped at -100 DegC, whereas at -75 DegC halogen migration gives rise to an isomer. As shown now, one can conveniently
如果去质子化引发的重卤素迁移的发生和结果可以预测,那么它们应该成为芳烃合成中最受欢迎的工具。特别吸引人但极其罕见的是停停的情况,其中由金属化产生的第一个中间体可以在 -100 摄氏度时被捕获,而在 -75 摄氏度时卤素迁移会产生异构体。如现在所示,人们可以在-100 摄氏度的甲苯中,在防止卤素迁移的条件下,通过卤素/金属相互转化方便地生产初始芳基锂物质,并通过在-75 摄氏度下添加 THF 来释放异构化过程。[关于 SciFinder (R)]