Atropisomers of 6,6'-dinitro-2,2'-diphenic acid were first experimentally described case, by Christie and Kenner (1922).
Atropisomers are stereoisomers arising because of hindered rotation about a single bond, where energy differences due to steric strain or other contributors create a barrier to rotation that is high enough to allow for isolation of individual conformers.[1][2]
They occur naturally and are important in pharmaceutical design.[3] When the substituents are achiral, these conformers are enantiomers (atropoenantiomers), showing axial chirality; otherwise they are diastereomers (atropodiastereomers).[1]
^ abBringmann, Gerhard; Mortimer, Anne J. Price; Keller, Paul A.; Gresser, Mary J.; Garner, James; Breuning, Matthias (2005). "Atroposelective Synthesis of Axially Chiral Biaryl Compounds". Angewandte Chemie International Edition. 44 (34): 5384–5427. doi:10.1002/anie.200462661. PMID16116589.
^Anslyn, Eric V.; Dougherty, Dennis A. (2006). Modern physical organic chemistry. Mill Valley, CA: University Science Books. ISBN1-891389-31-9. OCLC55600610.
^Clayden, Jonathan; Moran, Wesley J.; Edwards, Paul J.; LaPlante, Steven R. (2009). "The Challenge of Atropisomerism in Drug Discovery". Angew. Chem. Int. Ed. 48 (35): 6398–6401. doi:10.1002/anie.200901719. ISSN1433-7851. PMID19637174.