Krivosudský Lukáš, Schwendt Peter, Šimunek Ján, Gyepes Róbert
Department of Inorganic Chemistry, Comenius University, Faculty of Natural Sciences, Mlynská dolina, 842 15 Bratislava (Slovakia), Fax: (+421) 2-60296-273.
Chemistry. 2014 Jul 14;20(29):8872-5. doi: 10.1002/chem.201403125. Epub 2014 Jun 17.
Reported herein is a simple synthetic and crystallization procedure for sequential isolation of two stereoisomers of isoleucine-derived vanadium(V) complexes from a racemic mixture with three stereogenic centers and therefore eight hypothetical species. The products of this crystallization were characterized by electronic and vibrational circular dichroism, NMR spectroscopy, and polarimetry to compare the chiroptic properties of the enantiomerically pure analogues prepared from L-isoleucine and D-allo-isoleucine. NMR studies pointed to the yet unobserved phenomenon of vanadium-catalyzed epimerization of isoleucine.
本文报道了一种简单的合成和结晶程序，用于从具有三个立体中心因而有八个假定异构体的外消旋混合物中顺序分离异亮氨酸衍生的钒（V）配合物的两种立体异构体。通过电子和振动圆二色性、核磁共振光谱和旋光测定对该结晶产物进行了表征，以比较由L-异亮氨酸和D-别异亮氨酸制备的对映体纯类似物的手性光学性质。核磁共振研究指出了钒催化异亮氨酸差向异构化这一尚未观察到的现象。
