Synthesis of <i>C</i> _3v ‐Symmetrical 1,3,5‐Tris‐ <i>O</i> ‐Me‐Calix[6]arene: New Perspectives

The alternate O ‐methylation of p ‐ t Bu‐calix[6]arene is a well‐known method leading to the C 3v ‐symmetrical 1,3,5‐tris‐ O ‐Me‐ p ‐ t Bu‐calix[6]arene, a key compound for the development of platforms for supramolecular studies and in particular for the access to receptors in host–guest chemistry. The alternate O ‐methylation of the parent de‐ tert ‐butylated calix[6]arene remained elusive, precluding the development of similar C 3v ‐symmetrical 1,3,5‐tris‐ O ‐methylated receptors with an open cavity devoid of bulky t Bu groups at the large rim. In this work, we developed an efficient method for the synthesis of 1,3,5‐tris‐ O ‐Me‐calix[6]arene. This platform was further selectively derivatized on the small and large rims, producing notably a tris‐imidazole calix[6]arene‐based ligand forming a biomimetic funnel complex upon coordinating Zn 2+ , with an open cavity suitable for the inclusion of a bulky dopamine derivative.