Novel Spherand‐Type Calixarenes – Synthesis, Conformational Studies, and Isomer Separation

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Abstract
The novel macrocyclic compounds hexahydroxy[1.0.1.0.1.0]‐6b and octahydroxy[1.0.1.0.1.0.1.0]metacyclophane 6c have been prepared in 50–70% yield by base‐catalyzed condensation of 5,5′‐di‐tert1‐butyl‐2,2′‐dihydroxybiphenyl (5) with formaldehyde in xylene. The conformations of trimer 6b and tetramer 6c have been evaluated from their dynamic 1H‐NMR spectra. Methylation of the hydroxyl groups of 6b and 6c with MeI gives the corresponding methoxy[1n]metabiphenylophanes 7b and 7c in good yields. The metacyclophane 7b has been found to consist of two isomers, out of which one was separated pure. The structural characterization of these products is discussed.