Atropisomerism in a 10-Membered Ring with Multiple Chirality Axes: (3 Z ,9 Z )-1,2,5,8-Dithiadiazecine-6,7(5 H ,8 H )-dione Series

Vesna Risso (1) , Daniel Farran (1) , Guilhem Javierre (1) , Jean-Valère Naubron (2) , Michel Giorgi (2) , Patrick Piras (1) , Marion Jean (1) , Nicolas Vanthuyne (1) , Roberta Fruttero (3) , Dominique Lorcy (4) , Christian Roussel (1)

1 ISM2 - Institut des Sciences Moléculaires de Marseille
2 AMU SPEC - Spectropôle - Aix Marseille Université
3 University of Torino
4 ISCR - Institut des Sciences Chimiques de Rennes

For the first time, chirality in (3 Z,9 Z)-1,2,5,8-dithiadiazecine-6,7(5 H,8 H)-dione series was recognized. Enantiomers of the 4,9-dimethyl-5,8-diphenyl analogue were isolated at room temperature, and their thermal stability was determined. X-ray crystallography confirmed the occurrence of a pair of enantiomers in the crystal. Absolute configurations were assigned by comparing experimental and calculated vibrational/electronic circular dichroism spectra of isolated enantiomers. A distorted tesseract (four-dimensional hypercube) was used to visualize the calculated enantiomerization process, which requires the rotation around four chirality axes. Conformers of higher energy as well as several concurrent pathways of similar energies were revealed.

Domaines: Chimie

Vesna Risso, Daniel Farran, Guilhem Javierre, Jean-Valère Naubron, Michel Giorgi, et al.. Atropisomerism in a 10-Membered Ring with Multiple Chirality Axes: (3 Z ,9 Z )-1,2,5,8-Dithiadiazecine-6,7(5 H ,8 H )-dione Series. Journal of Organic Chemistry, 2018, 83 (15), pp.7566-7573. ⟨10.1021/acs.joc.8b01009⟩. ⟨hal-01817538⟩