Calixhydroquinones: a novel access to conformationally restricted, meta-substituted calixarenes
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Abstract
An efficient and versatile synthetic route to calixhydroquinones is described. These macrocycles are activated towards meta substitution, and reaction with bromine gives the first examples of persubstituted, phenol-derived calixarenes. The effect of meta substitution on calixarene mobility is demonstrated by the fixation of an otherwise mobile calix[4] system in the partial cone conformer, and the slowing of the ring inversion rate in calix[8]arenes.