Carba-Methylephedrine and Carba-<i>pseudo</i>-Methylephedrine as Tools for Probing the Role of the Nitrogen Atom of Chiral Amino Alcohols in Asymmetric Synthesis
作者:Dominique Cahard、Laurent Ferron、Jean-Christophe Plaquevent
DOI:10.1055/s-1999-3092
日期:——
As part of our on-going program on the use of chiral alkoxides as chiral bases in asymmetric synthesis, we report that carba-ephedrine analogues of N-methylephedrines, with a simple change of bridging nitrogen for CH, served to probe the role of the nitrogen atom in the discrimination of enantiotopic protons by means of the derived alkoxides. We suggest reasons why in the pseudo ephedrine series the asymmetric induction is retained while in the ephedrine series the enantioselectivity is stronlgy affected.
作为我们关于手性烷氧化物在不对称合成中作为手性碱的持续研究计划的一部分,我们报道了N-甲基麻黄碱的卡巴-伪麻黄碱类似物,通过简单的将桥接氮替换为CH,用于探测氮原子在通过衍生的烷氧化物区分对映异位质子中的作用。我们提出了为什么在伪麻黄碱系列中不对称诱导得以保留,而在麻黄碱系列中对映选择性受到强烈影响的原因。