- Steric effects which determine the conformational preferences and stereodynamic processes of aryl fluorenyl ketones
-
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.
- Casarini, Daniele,Lunazzi, Lodovico,Mazzanti, Andrea
-
supporting information; experimental part
p. 1619 - 1626
(2009/06/27)
-
- Stereomutation of conformational enantiomers of 9-isopropyl-9- formylfluorene and related acyl derivatives
-
(Figure Presented) Low-temperature NMR spectra show that the title compound exists as a pair of conformational enantiomers, generated by the restricted rotation about the C9-Pri bond, the corresponding interconversion barrier being 6.9 kcal mol-1. This interpretation is supported by theoretical (MM and DFT) calculations and by the experimental determination of the analogous barriers occurring in the related MeC=O and ButC=O derivatives.
- Casarini, Daniele,Lunazzi, Lodovico,Mazzanti, Andrea
-
p. 6382 - 6385
(2008/12/22)
-