Installation of a Chiral Side Chain to a 2-Alkylidene-1-cycloalkan-1-ol Unit by Using Allylic Substitution
作者:Chao Feng、Yuichi Kobayashi
DOI:10.1002/ejoc.201300792
日期:2013.10
The allylic substitution of optically active exocyclic allylic esters of cyclopentane and cyclohexane with ArMgBr-based copper reagents (Ar = aryl) was examined. ArMgBr/Cu(acac)2 in a 2:1 ratio was an adequate reagent to produce the anti-SN2′ products efficiently in terms of regioselectivity (95–99 %), chirality transfer (91–99 %), and yield (71–91 %). The Ar groups that were successfully installed
研究了环戊烷和环己烷的旋光环外烯丙基酯与基于 ArMgBr 的铜试剂(Ar = 芳基)的烯丙基取代。就区域选择性 (95–99%)、手性转移 (91–99%) 和产率 (71) 而言,比例为 2:1 的 ArMgBr/Cu(acac)2 是有效生产抗 SN2' 产物的合适试剂–91%)。成功安装的 Ar 基团包括 Ph 和 p-tolyl、具有给电子基团(即 p-MeOC6H4)和吸电子基团(即 p-FC6H4)的基团以及具有空间要求基团(即 o-甲苯基,o-MeOC6H4)。在测试烷基试剂时,BuMgBr/CuBr·Me2S 在 ZnI2 的存在下以 2:1 的比例提供具有高区域选择性 (99%) 和良好收率 (91%) 的产物。