Diaryl-Pyrano-Chromenes Atropisomers: Stereodynamics and Conformational Studies

Alessia Ciogli; Andrea Fochetti; Andrea Sorato; Giancarlo Fabrizi; Nunzio Matera; Andrea Mazzanti; Michele Mancinelli

doi:10.3390/molecules28134915

Diaryl-Pyrano-Chromenes Atropisomers: Stereodynamics and Conformational Studies

Molecules. 2023 Jun 22;28(13):4915. doi: 10.3390/molecules28134915.

Authors

Alessia Ciogli¹, Andrea Fochetti¹, Andrea Sorato¹, Giancarlo Fabrizi¹, Nunzio Matera², Andrea Mazzanti², Michele Mancinelli²

Affiliations

¹ Department of Chemistry and Drug Technologies, Sapienza University of Rome, Piazzale Aldo Moro 5, 00185 Roma, Italy.
² Department of Industrial Chemistry "Toso Montanari", University of Bologna, Viale del Risorgimento 4, 40136 Bologna, Italy.

Abstract

The dynamic scenario of di-aryls-pyrano-chromenes was investigated using DFT calculations. The symmetry of the chromene scaffold and the presence of two ortho-substituted aryls substituents can generate two syn/anti diastereoisomers and conformational enantiomers with different rotational barriers. The relative conformations and configurations were derived using NOESY-1D experiments. Depending on the energies related to the conformational exchange, the experimental energy barriers were determined through Dynamic NMR, Dynamic HPLC or kinetic studies. The atropisomeric pairs were resolved in the latter scenario, and their absolute configuration was assigned using the ECD/TD-DFT method.

Keywords: DFT; Dynamic-HPLC; Dynamic-NMR; ECD; TD-DFT; aryls-pyrano-chromenes; atropisomer.

MeSH terms

Benzopyrans*
Density Functional Theory
Kinetics
Magnetic Resonance Spectroscopy
Molecular Conformation

Substances

Benzopyrans

Grants and funding

The University of Bologna is gratefully acknowledged (RFO Funds 2021 and 2022). A.M., M.M., and N.M. thank Alchemy SrL, Bologna, for the generous gift of chemicals. The authors of the Department of Chemistry and Drug Technologies are gratefully acknowledged to Sapienza (RM1221816BF705A8 found).