Aldol Reactions between L-Erythrulose Derivatives and Chiral α-Amino and α-Fluoro Aldehydes: Competition between Felkin-Anh and Cornforth Transition States
作者:Santiago Díaz-Oltra、Miguel Carda、Juan Murga、Eva Falomir、J. Alberto Marco
DOI:10.1002/chem.200800956
日期:2008.10.20
Both matched and mismatched diastereoselection have been observed in aldol reactions of a boron enolate of a protected L-erythrulose derivative with several chiral alpha-fluoro and alpha-amino aldehydes. Strict adherence to the Felkin-Anh model for the respective transition structures does not account satisfactorily for all the observed results, as previously observed in the case of alpha-oxygenated
在受保护的L-赤藓糖衍生物的硼烯酸酯与几种手性α-氟和α-氨基醛的醛醇缩合反应中已经观察到匹配的和错配的非对映选择性。如先前在α-氧化醛的情况下所观察到的,对于各个过渡结构严格遵守Felkin-Anh模型并不能令人满意地解决所有观察到的结果。在某些情况下,只有Cornforth模型提供了很好的解释。讨论了影响该二分法的因素,并提出了用于与α-杂原子取代的醛的醛醇缩合反应的通用机理模型。该模型的其他支持是从密度泛函计算中获得的。