Synthesis of <i>meso</i> -Unsubstituted and/or <i>meso</i> -Spiroadamantyl-Substituted Tetrapyrrole Macrocycles Scrambling Oligopyrrole Precursors into <i>cis</i> - and <i>trans</i> -Arranged Cyclic Arrays

Calix[4]pyrroles with unsubstituted meso -positions were synthesized by precipitating the products from reaction mixtures. The introduction of meso -spiroadamantyl subunits resulted in the scrambling of oligopyrrole intermediates during [2 + 2] condensation reactions. This process afforded a combination of cis - and trans -arranged isomers, as well as significant spectroscopic modifications arising from close contacts between the adjacent π-planes by the bulky adamantyl groups attached to the meso -positions in a spiro configuration.