VCD study of alpha-methylbenzyl amine derivatives: detection of the unchanged chiral motif.
VCD study of alpha-methylbenzyl amine derivatives: detection of the unchanged chiral motif.
复制标题
α-甲基苄胺衍生物的 VCD 研究：检测未改变的手性基序。
作者：
Christian Merten;M. Amkreutz;A. Hartwig
手性α-甲基苄基胺是众所周知的且经常使用的手性助剂，例如，外消旋体的拆分或不对称催化。本文采用振动圆二色谱（VCD）和密度泛函理论（DFT）对α-甲基苄胺及其衍生物N，α-二甲基苄胺、N，N，α-三甲基苄胺和双[α-甲基苄胺]进行了研究。通过DFT计算得到了所有化合物的稳定的低能构象，并在此基础上计算了它们的理论振动吸收谱和VCD谱，并与实验结果进行了比较。因此，确定了绝对构型和构象偏好。所有的实验VCD光谱的计算支持的研究的手性分子的定性比较，这清楚地表明不同的手性胺的光谱之间的相似性。这些可以归因于不变的手性中心的振动。
Chiral alpha-methylbenzyl amine is a well known and often used chiral auxiliary, e.g., in the resolution of racemates or asymmetric catalysis. In this work, alpha-methylbenzyl amine and its derivatives N,alpha-dimethylbenzyl amine, N,N,alpha-trimethylbenzyl amine, and bis[alpha-methylbenzyl] amine were investigated by vibrational circular dichroism (VCD) spectroscopy and density functional theory (DFT). For all compounds, stable low energy conformers were obtained by the DFT calculations and based on those, the theoretical vibrational absorption (VA) and VCD spectra were calculated and compared with experimental spectra. Hence, the absolute configurations and conformational preferences were determined. A qualitative comparison of all the experimental VCD spectra of the investigated chiral molecules supported by the calculated ones is given which clearly shows similarities between the spectra of the different chiral amines. These can be assigned to vibrations of the unchanged chiral center.