Buttressing Effects Rerouting the Deprotonation and Functionalization of 1,3-Dichloro- and 1,3-Dibromobenzene
作者:Christophe Heiss、Elena Marzi、Manfred Schlosser
DOI:10.1002/ejoc.200300355
日期:2003.12
A systematic comparison between 1,3-difluorobenzene, 1,3-dichlorobenzene, and 1,3-dibromobenzene did not reveal major differences in their behavior towards strong bases such as lithium diisopropylamide or lithium 2,2,6,6-tetramethylpiperidide. Thus, all 2,6-dihalobenzoic acids are directly accessible by consecutive treatment with a suitable base and dry ice. In contrast, (2,6-dichlorophenyl)- and (2
1,3-二氟苯、1,3-二氯苯和 1,3-二溴苯之间的系统比较并未揭示它们对强碱(如二异丙基氨基锂或 2,2,6,6-四甲基哌啶锂)行为的重大差异。因此,通过用合适的碱和干冰连续处理,所有 2,6-二卤代苯甲酸都可以直接获得。相比之下,(2,6-二氯苯基)-和(2,6-溴苯基)三乙基硅烷在 5-位进行去质子化(提供 4-羧基衍生物和脱保护后的 3,5-二卤代苯甲酸),而 1已知 ,3-二氟类似物在 4-位反应。2,4-二卤代苯甲酸被选择性地制备。从硅烷通过在 4 位溴化,相邻位置的金属化和羧化,然后脱甲硅烷基化和脱溴或 1,3-dihalo-2-iodobenzos 通过碱促进碘迁移到 4 位,然后碘/镁置换和随后的羧化。[在 SciFinder (R) 上]