Synthesis of meso -Unsubstituted and/or meso -Spiroadamantyl-Substituted Tetrapyrrole Macrocycles Scrambling Oligopyrrole Precursors into cis - and trans -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.