SYNTHESES OF CALIX[4]NAPHTHALENES DERIVED FROM 1-NAPHTHOL

Using a convergent synthetic strategy, the synthesis of the previously elusive C-4v-symmetrical calix[4]naphthalene from 1-naphthol is described. Using other independent convergent routes, syntheses of the other three isomeric calix[4]naphthalenes originally formed from the direct base-catalyzed condensation of formaldehyde with 1-naphthol are also described. All of these methods involved either a TiCl4- or TFA-assisted coupling reaction to achieve the cyclization steps. A mechanism is proposed to account for the formation of the original three isomeric calix[4]naphthalenes from the base-catalyzed condensation of formaldehyde with 1-naphthol.