Synthesis of organozinc enolates of N,N-disubstituted glycine esters. Crystal structure of [Et(t-Bu)Me]4
作者:Fred H. van der Steen、Jaap Boersma、Anthony L. Spek、Gerard van Koten
DOI:10.1016/0022-328x(90)85039-2
日期:1990.7
Pure ethylzinc α-amino ester enolates have been prepared from N,N-disubstituted glycine esters and N-(ethylzinc)diisopropylamine. An X-ray diffraction study of Et(t-Bu)Me (2b) has shown it to be a tetrameric species, in which the four crystallographically independent zinc enolate units are interconnected via covalent ZnOZn bridges. As a result of intramolecular ZnN coordination, all the enolate
由N,N-二取代的甘氨酸酯和N-(乙基锌)二异丙胺制备了纯的乙基锌α-氨基酯烯酸酯。对Et (t-Bu)Me(2b)的X射线衍射研究表明,它是四聚体,其中四个晶体学上独立的烯醇酸锌单元通过共价ZnOZn桥相互连接。由于分子内ZnN配位,所有烯醇部分均具有Z构型。2b情况下的1 H NMR光谱和分子量测定表明在苯中,四聚体与二聚体处于平衡状态。在二聚体中,ZnN配位能力弱,导致氮快速开关运动,或者完全不存在。