Method for the Preparation of Derivatives of Heptiptycene: Toward Dual-Cavity Baskets

Abstract

We have developed a novel synthetic method that enables the preparation of functional derivatives of heptiptycene, i.e., cavitands with two juxtaposed cavities. The homocoupling of bicyclic dibromoalkenes is promoted by Pd­(OAc)₂ (10%) in dioxane (100 °C) to give cyclotrimers in 27–77% yield under optimized reaction conditions (Ph₃P, K₂CO₃, <i>n</i>-Bu₄NBr, N₂, 4 Å MS). These dual-cavity baskets show a strong π → π* absorption at 241 nm (ε = 939 000 M^–1 cm^–1), along with a subsequent fluorescence emission at 305 nm