Determination of the Absolute Configuration of Amines and α-Amino Acids by <sup>1</sup>H NMR of (<i>R</i>)-<i>O</i>-Aryllactic Acid Amides
作者:Rafael Chinchilla、Larry R. Falvello、Carmen Nájera
DOI:10.1021/jo9604191
日期:1996.1.1
(R)-O-Aryllactic acid (ROAL) amides derived from alpha-chiral primary amines and alpha-amino acid esters show different chemical shifts in (1)H NMR spectroscopy (300 MHz) depending on their configuration. Molecular mechanics, semiempirical calculations, and (1)H NMR studies suggest that, in solution, these amides prefer an ap-Z conformation with the C(alpha)OAr and C=O groups close to anti-periplanar
衍生自α-手性伯胺和α-氨基酸酯的(R)-O-丙烯酸(ROAL)酰胺根据其构型在(1)H NMR光谱(300 MHz)中显示不同的化学位移。分子力学,半经验计算和(1)H NMR研究表明,在溶液中,这些酰胺更喜欢ap-Z构象,其中CαOOAr和C = O基团与反平面相似,类似于扁桃体。酰胺。所提出的构象偏好不同于ROAL酯的构象偏好(在顺周构象中为CαH和C = O基团)。ROAL酰胺的构象模型允许根据芳基和胺部分上的取代基的相对位置以及它们的对映体组成,对伯胺和α-氨基酸酯进行绝对构型分配。