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Updated: Jun 10, 2026

Preparation of Enantiopure Non-Activated Aziridines and Synthesis of Biemamide B, D, and epiallo-Isomuscarine
Published on: June 13, 2022
Stereomutation of axially chiral aryl coumarins
Lodovico Lunazzi1, Michele Mancinelli, Andrea Mazzanti
1Department of Organic Chemistry A. Mangini, University of Bologna, Viale Risorgimento 4, Bologna 40136, Italy.
Abstract:
Coumarins substituted by an aryl group in position 4 display restricted rotation about the Ar-C4 bond, giving rise to conformational or configurational enantiomers (atropisomers) when such a restricted motion leads to a C(1) symmetry. The dynamics of the stereomutation processes of these axial enantiomers was monitored by dynamic NMR, dynamic enantioselective HPLC, or racemization kinetics, depending on the activation energies involved. These results were further supported by DFT computations. In the two cases where the enantiomers were sufficiently long living as to be physically separated at ambient temperature, the absolute configuration was determined by means of a theoretical simulation of their electronic circular dichroism spectra (ECD).
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