C-3-Symmetric Tricyclo[2.2.1.0(2,6)]heptane-3,5,7-triol

摘要

A straightforward access to a hitherto unknown C-3-symmetric tricyclic triol both in racemic and enantiopure forms has been developed. Treatment of 7-tert-butoxynorbornadiene with peroxycarboxylic acids provided mixtures of C-1- and C-3-symmetric 3,5,7-triacyloxynortricyclenes via transannular -cyclization and replacement of the tert-butoxy group. By refluxing in formic acid, the C-1-symmetric esters were converted to the C-3-symmetric formate. Hydrolysis gave diastereoisomeric triols, which were separated by recrystallization. Enantiomer resolution via diastereoisomeric tri(O-methylmandelates) delivered the target triols on a gram scale. The pure enantiomers are useful as core units of dopants for liquid crystals.