Chedid Roland Bou, Fröhlich Roland, Hoppe Dieter
Organisch-Chemisches Institut, Westfälische Wilhelms-Universität Münster, Germany.
Org Lett. 2006 Jul 6;8(14):3061-4. doi: 10.1021/ol061005p.
[reaction: see text] Lithium compounds 7 are configurationally stable intermediates obtained by deprotonation of 1,3-dien-2-yl carbamates 6 with n-butyllithium/(-)-sparteine with a high degree of enantiotopic differentiation at the gamma-position. They react with electrophiles regioselectively giving highly enantioenriched products. Starting with different isomers or changing the double-bond geometries in 6 leads to either of the enantiomers.
[反应:见正文] 锂化合物7是通过用正丁基锂/(-)-鹰爪豆碱使1,3-二烯-2-基氨基甲酸酯6去质子化而得到的构型稳定的中间体,在γ-位具有高度的对映体选择性区分。它们与亲电试剂发生区域选择性反应,生成高度对映体富集的产物。从不同的异构体开始或改变6中的双键几何结构会得到两种对映体中的任意一种。