Unusually rigid macrocyclic tris(picolinolato)-4-tert-butylcalix[4]arene: Its intramolecular interaction effect on picolinoylation

► An unprecedented tris-substituted calix[4]arene derivative was synthesized. ► Steric hindrance and weak intramolecular interactions are key factors. ► The quite up-field aromatic chemical shift means the extremely rigid structure.