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

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 (H-1, C-13) and mass (MALDI-TOF) spectra. Their solid-state conformations are elucidated by X-ray crystallographic analyses.