Novel Approach to the (-)-Sparteine-Mediated Synthesis of Kainoids:Total Synthesis of (-)-α-Kainic Acid by (-)-Sparteine-Mediated Deprotonation
作者:M. Montserrat Martínez、Dieter Hoppe
DOI:10.1002/ejoc.200400824
日期:2005.4
We report a new synthesis of kainoids via allyllithium compounds using an intramolecular cycloalkylation as the key step. Preparation of different substituted pyrrolidines was carried out by using carbamates, that react with the chiral base n-BuLi/(–)-sparteine with strong selection between the diastereotopic protons adjacent to the carbamate group in favour for the pro-S proton. (–)-α-Kainic acid was
我们报告了使用分子内环烷基化作为关键步骤通过烯丙基锂化合物合成类胡萝卜素的新方法。通过使用氨基甲酸酯制备不同的取代吡咯烷,氨基甲酸酯与手性碱 n-BuLi/(-)-sparteine 反应,在与氨基甲酸酯基团相邻的非对映质子之间进行强选择,有利于 pro-S 质子。(-)-α-红藻氨酸由 D-丝氨酸甲酯盐酸盐合成,基于中间体氨基甲酸酯的 (-)-sparteine 介导的不对称去质子化,通过立体定向抗 SN'SE' 分子内环烷基化,导致(-)-α-红藻氨酸的吡咯烷环前体,具有高产率和非对映选择性。相关的方法,从L-谷氨酸开始失败了。中间体吡咯烷分三步进一步转化为 (-)-α-红藻氨酸。