Bromination and iodination of donor–acceptor cyclopropanes. Evidence for an ET mechanism
作者:Vincenzo Piccialli、M.Liliana Graziano、M.Rosaria Iesce、Flavio Cermola
DOI:10.1016/s0040-4039(02)01966-4
日期:2002.11
presence of pyridine, NBS, trimethyl phosphate, and iodination with ICl and ICl/pyridine has been also performed. A common SET mechanism may be proposed for both halogenations; depending on the reaction conditions, bromination can also occur via acid-catalysed or SE2 routes. The reaction of the 2-ethoxyanalogues cis-12 and trans-12 with the same halogens proceeds in a similar manner, giving 3-formyl-2-haloesters
2,2-二甲氧基环丙烷甲酸乙酯1a – d容易与Br 2和I 2在CCl 4或CH 2 Cl 2中反应,高产率地分别生成1-乙基-4-甲基2-卤代丁二酸酯2和3。还已经在吡啶,NBS,磷酸三甲酯存在下进行溴化,并用ICl和ICl /吡啶进行碘化。对于两种卤化,可以提出通用的SET机制。取决于反应条件,也可以通过酸催化的或S发生溴化ë 2个路由。2- ethoxyanalogues的反应顺- 12和反式- 12用相同的卤素前进以类似的方式,得到3-甲酰基-2-卤代酯与相应的diethylacetals作为主要产物一起。还研究了用催化体系NaI / m -CPBA / 18-crown-6对12的碘化。