Density Functional Theory Calculations of the Optical Rotation and Electronic Circular Dichroism: The Absolute Configuration of the Highly Flexible <i>trans</i>-Isocytoxazone Revised
作者:Marcin Kwit、Maria D. Rozwadowska、Jacek Gawroński、Agnieszka Grajewska
DOI:10.1021/jo901175s
日期:2009.11.6
that the most frequently used B3LYP/6-31G(d) method is not adequate for prediction of the absolute configuration of this type of highly flexible molecules. The absolute configurations of levorotatory trans-isocytoxazone 2 and analogues 1, 3, and 4 have been established as (−)-(4S,5S)-trans-1−4; i.e., it is in opposition to the previously published configuration (−)-(4R,5R)-trans-2.
从头的一系列旋光计算(OR)和电子圆二色性(ECD)反式的天然细胞因子调节剂cytoxazone的-diastereomers 1 - 4已经通过密度泛函理论(DFT)进行了研究。经过严格评估,OR和ECD曲线的计算提供了一种可靠的方法来分配这些构象柔性分子的绝对构型。讨论了用于计算的理论水平,构象异构体平衡的变化以及溶剂对计算的OR数据的几何形状和值的影响,得出结论,认为最常用的B3LYP / 6-31G(d)方法不足以预测这种类型的高度柔性分子的绝对构型。左旋的绝对构型反式-isocytoxazone 2和类似物1,3,和4已被确定为( - ) - (4小号,5小号) -反式- 1 - 4 ; 即,它与先前公开的构型(-)-(4 R,5 R)-trans - 2相反。