A series of metacyclophanes consisting of three aromatic rings have been pr
epared. The detailed study of their conformational properties by means of t
he NMR spectroscopy and the X-ray analysis confirmed the "n,m-alternate(fol
ded-inwards)" and "n,m-alternate(cone-like)" conformations. Two conformers
of 3a exhibited a different reactivity in demethylation by BBr3.