The title reaction initially produced a mixture of three cyclic oligomers, calix[n]resorcinarenes (n = 4, 5, 6), as the major products. Under the conditions of their formation, the pentamer rapidly isomerized to the tetramer and the hexamer, while the hexamer slowly isomerized to the tetramer. A new cyclic oligomer, calix[5]resorcinarene, was isolated and characterized. Copyright (C) 1996 Elsevier Science Ltd