C3‐Symmetric Tricyclo[2.2.1.02,6]heptane‐3,5,7‐triol

A straightforward access to a hitherto unknown C3‐symmetric tricyclic triol both in racemic and enantiopure forms has been developed. Treatment of 7‐tert‐butoxynorbornadiene with peroxycarboxylic acids provided mixtures of C1‐ and C3‐symmetric 3,5,7‐triacyloxynortricyclenes via transannular π‐cyclization and replacement of the tert‐butoxy group. By refluxing in formic acid, the C1‐symmetric esters were converted to the C3‐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. Advances in C3 symmetry: The hitherto unknown smallest C3‐symmetric tricyclic triol has been synthesized in both enantiomeric forms. Reactions of 7‐tert‐butoxynorbornadiene with peroxy acids led to C1‐symmetric triesters, which were subsequently isomerized to C3‐symmetric products. Classical racemate resolution provided the enantiomerically pure target compounds, which are suitable for the preparation of dopants for liquid crystals.