Dova Davide, Cauteruccio Silvia, Prager Stefan, Dreuw Andreas, Graiff Claudia, Licandro Emanuela
†Dipartimento di Chimica, Università degli Studi di Milano, via Golgi 19, I-20133 Milan, Italy.
‡Interdisciplinary Center for Scientific Computing, Heidelberg University, Im Neuenheimer Feld 368, 69120 Heidelberg, Germany.
J Org Chem. 2015 Apr 17;80(8):3921-8. doi: 10.1021/acs.joc.5b00243. Epub 2015 Mar 26.
Chiral helical-based phosphanes are challenging and promising ligands, with a great potential for the generation of both organic and organometallic catalysts. We report here the preparation of novel chiral thiahelicene-based alkyl phosphanes, isolated and characterized as air-stable borane adducts, and the investigation of their experimental and theoretical (chir)optical properties. X-ray characterization of a mono- and a disubstituted derivative as a racemic mixture has been performed, which confirms the influence of the number and nature of substituents on the flexibility of the helix. In addition, the absolute configuration inferred from CD spectra of the two enantiomers of a diborane complex has been established from X-ray analysis. State-of-the-art quantum chemical calculations of vibrationally resolved spectra allow, for the first time, for an unambiguous assignment of the experimentally observed peaks in linear absorption and circular dichroism spectra to excited electronic states of this class of thiahelicene phosphorus derivatives.
基于手性螺旋的膦是具有挑战性且有前景的配体，在生成有机和有机金属催化剂方面具有巨大潜力。我们在此报告了新型基于手性硫杂并苯的烷基膦的制备，其作为空气稳定的硼烷加合物被分离和表征，并对其实验和理论（手性）光学性质进行了研究。已对作为外消旋混合物的单取代和双取代衍生物进行了X射线表征，这证实了取代基的数量和性质对螺旋柔性的影响。此外，通过X射线分析确定了二硼烷配合物两种对映体的CD光谱推断出的绝对构型。对振动分辨光谱的最新量子化学计算首次允许将线性吸收和圆二色光谱中实验观察到的峰明确归属为这类硫杂并苯磷衍生物的激发电子态。
