Highly Diastereoselective Lithiation and Substitution of an (S)-Prolinyl Thiocarbamate via Sterically Homogeneous Lithio(thiocarbamate): Synthesis of Enantiomerically Pure Prolinethiols
作者:Ravindra P. Sonawane、Christian Mück-Lichtenfeld、Roland Fröhlich、Klaus Bergander、Dieter Hoppe
DOI:10.1002/chem.200601853
日期:2007.7.27
Highly diastereoselective lithiation-substitution reactions of an (S)-proline derived S-alkyl thiocarbamate was accomplished. The configuration of the predominant alkyllithium species and the stereochemical course of the electrophilic substitution reactions are deduced by a combination of X-ray crystal structure analysis, NMR spectroscopic studies, deuteration/dedeuteration experiments, and quantum
(S)-脯氨酸衍生的S-烷基硫代氨基甲酸酯的高度非对映选择性锂化-取代反应得以完成。通过结合X射线晶体结构分析,NMR光谱研究,氘/氘化实验和量子化学计算,推导了主要烷基锂物质的构型和亲电取代反应的立体化学过程。发现锂中间体(S,S)-9在动力学和热力学上均受青睐,而(S,R)-9迅速出现差向异构。