Transannular Diels–Alder reactions on 14-membered macrocyclic trienes. Part II: formation of macrocycles and thermal conversion into tricyclic systems

In the preceding paper (Part I) we described the synthesis of eight isomeric acyclic trienes. These compounds could be transformed into the corresponding macrocyclic trienes, which were further converted into tricyclic A.B.C.[6.6.6] products by a thermal transannular Diels–Alder reaction. The experimental results of this study and their analysis are reported in the present paper. The comparison with theoretical predictions is also discussed.