Synthesis of Hexahomotrioxacalix[3]naphthalenes and a Study of Their Alkali-Metal Cation Binding Properties

The first syntheses of the C3-symmetrical and unsymmetrical hexahomotrioxacalix[3]naphthalenes 3 and 4, respectively, and the corresponding tert-butyl hexahomotrioxacalix[3]naphthalene 3a are reported. A convergent synthesis of the linear hexahomotrimer precursors 19 and 19a is described, but the direct synthesis of 3 and 3a can also be achieved from the monomers 20 and 20a, respectively. A limited study of the binding properties of alkali-metal cations by 3 or 3a using a picrate-CHCl3 extraction showed only weak abilities to bind with the cations examined.