Isolable compounds displaying new fundamental forms of conformational isomerism were last discovered in 1914 (atropisomerism) and 1961 (hindered pyramidal inversion). Now, a new form - referred to as akamptisomerism - has been described through four resolved stereoisomers of a transoid (BF)O(BF)- quinoxalinoporphyrin compound. The stereodescriptors parvo and amplo, necessary for their classification, have also been introduced.

Peter J. Canfield, Iain M. Blake, Zheng-Li Cai, Ian J. Luck, Elmars Krausz, Rika Kobayashi, Jeffrey R. Reimers & Maxwell J. Crossley

Nature Chemistry 10, 615-624(2018) doi: 10.1038/s41557-018-0043-6