Serial synthesis of oxa[3.n]cyclophanes and homooxacalix[n]arenes via reductive coupling of arenedialdehydes, and their X-ray structures

Abstract

A wide range of oxa[3._n]cyclophanes and homooxacalix[n]arenes is prepared from the corresponding arenedialdehyde via reductive homocoupling reaction in a one-pot fashion. Heterocoupling reaction of arenedialdehyde with bis(trimethylsilyloxymethyl)benzene provides a series of macrocyclic ethers including a new type of oxacalixarene, which consists of the moieties of oxa[3._n]cyclophane and homooxacalix[n]arene; m- or p-phenylene, and 5-substituted 2-methoxy-m-phenylene are tethered by CH₂OCH₂ linkages. A series of macrocycles are separated with gel permeation chromatography (GPC) and identified with NMR (¹H, ¹³C) and mass (MALDI-TOF) spectra. Their solid-state conformations are elucidated by X-ray crystallographic analyses.