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The novel macrocyclic compounds, hexadecahydroxy[(1.0) 8 ]-(2c) and hexahydroxy[3.0.1.0.1.0]-metacyclophane (3) are isolated in 1.9 and 2.4% yields, respectively, from the reaction mixture obtained by CsOH-catalysed condensation of 5,5-di-tert-butyl-2,2-dihydroxybiphenyl 1 with formaldehyde under xylene reflux.

Regioselective O‐benzylations of [3.1.3.1]metacyclophanes with intraannular OH groups are described. O‐Benzylation of 6,13,22,29‐tetra‐tert‐butyl‐9,16,25,32‐tetrahydroxyy[3.1.3.1]metacyclophane 1 with 2 equiv. of benzyl bromide in the presence of Na2CO3 leads to exclusive formation of the monosubstituted product 3. In contrast, use of K2CO3 as the base leads to di‐O‐substitution, resulting in the disubstituted product, distal‐4, as the major product, along with some 1,2‐proximal‐4, in spite of using a large excess of benzyl bromide. Under the same reaction conditions in the presence of Cs2CO3, a mixture of two conformers of the tetra‐O‐benzylated product 2 in a ratio of 80:20 (cone‐2‐1,4‐alternate‐2) is obtained in 83% yield. Thus, the alkali metal cation plays not only an important role with regard to the regioselectivity, but also in determining the number of O‐benzylations that occur, as a consequence of the template effect. Regioselective syntheses of dimethoxy‐ and trimethoxy[3.1.3.1]metacyclophanes are accomplished by a protection‐deprotection strategy, using the benzyl residues as protecting groups. The 1H‐NMR spectra of these macrocyclic metacyclophanes are also discussed.

Base-catalyzed condensation of 1,2-bis[5-tert-butyl-3-(5-tertbutylsalicyl)-2-hydroxyphenyl]ethane (8) with formaldehyde in xylene affords a novel ethylene-bridged calixarene-analogous macrocyclic metacyclophane. However, not the desired 2 has been obtained. Instead, the novel macrocyclic cornpounds pentahydroxy[2.1.2.1.1]-(9) and hexahydroxy-[2.l.l.l.l.l]metacyclophane (10) have been isolated in 35 and 25% yields, respectively. The mechanism for the above disproportionation occurring during the base-catalyzed condensation of 8 to afford these macrocyclic metacyclophanes and their 'H-NMR spectral behavior are discussed.Extensive studies of calixarenes have been carried out during the last decade"]. Calixarenes are readily obtained by base-induced condensation of p-substituted phenols with demonstrating that the aromatic rings are invariably connected by methylene bridges. Their phenolic hydroxyl groups are ordered in well-shaped cyclic arrays due to strong intramolecular hydrogen b o n d~ [~-~] .In view of this fact it seems to be surprising that there are very few reports on the preparation of calixarenes containing bridges other than methylene units and on the characterization of their hydrogen bonding17-' ' 1.Recently, we have found a convenient synthesis of ethylene-bridged calixarene-analogous metacyclophanes 4 involving base-catalyzed condensation of 1,2-bis(5-tert-butylxylene, which discloses the unique properties of these compounds[' l]. They contain methylene and ethylene bridges in a ratio of 1 : 1. 2-hydroxypheny1)ethane (3) with formaldehyde in refluxing 1This strategy is supposed to be employed for the preparation of octahydroxy[2.1.1.1.2.1.l.l]metacyclophane 2 and its analogues by using the same condensation reaction of 1,2-bis[5-tert-butyl-3-(5-tert-butylsalicy1)-2-hydroxyphenyl]-ethane (8) with formaldehyde. Since the intramolecular hydrogen bonding between the hydroxyl groups of the diarylmethane units may be stronger than that between the hydroxy groups of the diarylethane units, the formation of a 1 : 2 complex of 8 with alkali metal ion may be possible in a "pleated loop" conformation like calix [8]arene l r 4 3 1 2 ] .In this paper, we report on the preparation and conformational properties of novel ethylene-bridged calixareneanalogous macrocyclic metacyclophanes 9 and 10.