Stereomutation of conformational enantiomers of 9-isopropyl-9-formylfluorene and related acyl derivatives.
Low-temperature NMR spectra show that the title compound exists as a pair of conformational enantiomers, generated by the restricted rotation about the C9-Pr (i) 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 Bu(t)C=O derivatives.
Casarini
Daniele
D
Department of Chemistry, University of Basilicata, via N. Sauro 85, Potenza 85100, Italy. casarini@unibas.it
Lunazzi
Lodovico
L
Mazzanti
Andrea
A