Rapid atropisomerization of 1,1′:5′,1″-ternaphthalene-2,2′,6′,2″-tetrol (TERNOL) and its inhibition by tethering at positions 7 and 7″

Atropisomerization of 1,1′:5′,1″-ternaphthalene-2,2′,6′,2″-tetrol (TERNOL) is very fast under basic conditions. The stereochemical instability is attributed to the nature of oxide anion of the central 2,6-naphthodiol moiety. Ring-closing metathesis of 7,7″-diallyloxy TERNOL results in intramolecular tethering in a high yield, which intrinsically inhibits the rapid isomerization. Bidentate sites in the tethered TERNOL are proved to have enough structural flexibility as an axial chiral ligand.