T. Yamato et al., SYNTHESIS AND CONFORMATIONAL STUDIES OF PENTAHYDROXY[2.1.2.1.1]METACYCLOPHANES AND HEXAHYDROXY[2.1.1.1.1.1]METACYCLOPHANES, Liebigs Annalen, (2), 1995, pp. 285-289
Base-catalyzed condensation of tyl-3-(5-tert-butylsalicyl)-2-hydroxyph
enyl]ethane (8) with formaldehyde in xylene affords a novel ethylene-b
ridged calixarene-analogous macrocyclic metacyclophane. However, not t
he desired 2 has been obtained. Instead, the novel macrocyclic compoun
ds pentahydroxy[2.1.2.1.1]- (9) and hexahydroxy-[2.1.1.1.1.1]metacyclo
phane (10) have been isolated in 35 and 25% yields, respectively. The
mechanism for the above disproportionation occurring during the base-c
atalyzed condensation of 8 to afford these macrocyclic metacyclophanes
and their H-1-NMR spectral behavior are discussed.