AbstractThe temperature‐dependent1H NMR spectrum of cyclo{tetrakis[(2‐hydroxy‐5‐(1,1,3,3‐tetramethylbutyl)‐1,3‐phenylene)methylene]}1e, a 4‐(1,1,3,3‐tetramethylbutyl)phenolformaldehyde cyclic tetracondensate, is described. From this the activation parameters in chloroform at 25°C for ring inversion (turning the pyramid inside out) of the truncated pyramid conformation of1ewere calculated: ΔG≠= 16,03 kcal/mol (67,1 kJ/mol), ΔH≠= 26,1 kcal/mol (109 kJ/mol), and ΔS≠= 34 cal mol−1K−1(141 J mol−1K−1). The1H NMR spectrum of the corresponding tetraacetate2was found to be ess