Steric effects which determine the conformational preferences and stereodynamic processes of aryl fluorenyl ketones
作者:Daniele Casarini、Lodovico Lunazzi、Andrea Mazzanti
DOI:10.1039/b822874d
日期:——
The stereodynamic processes and conformational preferences of two classes of aryl fluorenyl ketones have been investigated by means of dynamic NMR spectroscopy, DFT calculations and X-ray diffraction. When the aryl substituent has two hydrogens in the ortho positions, its rotation is independent of that of the fluorene ring. In contrast, if the two ortho hydrogens are replaced by the bulkier methyl groups (e.g. mesityl fluorenyl ketones), the motion of the aryl ring interacts with the fluorene, and the two rings rotate in a correlated manner.
通过动态核磁共振光谱、DFT计算和X射线衍射研究了两类芳基氟烯酮的立体动力学过程和构象偏好。当芳基取代基在邻位具有两个氢时,其旋转与氟烯环的旋转是独立的。相反,如果两个邻位氢原子被体积更大的甲基取代(例如美克氟烯酮),则芳基环的运动与氟烯有所相互作用,两环以相关的方式旋转。