2, 3, 4, 5-Tetrahedro-1-benzoxepin (8) and its 3-substituted derivatives (9-13) have been studied by 1H and 13C dynamic nuclear magnetic resonance in a few solvent systems. The results show that, while 8 and its methyl derivative 9 exist solely in chair forms (C for 8 and C e: C a (96: 4) for 9), the twist-boat (TB) conformation contributes significantly to the conformational equilibria of the derivatives 3-methoxy 10 (C a: C e: TB, 70: 20: 10), 3, 3- ...
