Convenient Formation of Six- to Nine-Membered Carbocyclic Rings by 2-Pyridyl Radical Cyclization: A Generalized Synthesis of Pyridine-Fused Linear Tricyclic Systems
作者:Asish Kr. Banerjee、Sarbendu Maiti、Michael G. Drew、Ranjan Mukhopadhyay、Basudeb Achari
DOI:10.1055/s-2005-916034
日期:——
substituted methylenecycloalkanes 19-22, vinylcycloalkanols 23 and 24, allylcycloalkanols 26-28, and butenylcycloalkanols 32-34 proceed via6-, 7-, 8-, and 9-endo-trig pathways, giving six-, seven-, eight-, and nine-membered ring annulated pyridines respectively. However, the vinyl cyclopentanol 25 produced only the 6-exo-cyclized product 46, while the substituted allylcyclohexanol 29 and the butenylcyclohexanol
衍生自 2-溴吡啶-3-基取代的亚甲基环烷醇 19-22、乙烯基环烷醇 23 和 24、烯丙基环烷醇 26-28 和丁烯基环烷醇 32-34 的 2-吡啶基自由基的分子内环化通过 6-、7-、8- 和 9- 进行endo-trig 通路,分别产生六元环、七元环、八元环和九元环的吡啶。然而,乙烯基环戊醇25仅产生6-外环化产物46,而取代的烯丙基环己醇29和丁烯基环己醇31未能环化,仅产生双键异构化脱溴烯烃。因此,该方法为研究不同类别的稠合吡啶提供了有用的途径,环烷烃的环大小和环中存在的其他取代基在决定反应结果方面起着重要作用。