Tröger's Base-Embedded Pillararenes─Macrocycles with Both Fixed and Conformational Chirality.

Tröger's base-embedded pillararenes (), which combine Tröger's base () with dialkoxybenzene units, were prepared via a fragment-coupling macrocyclization strategy. The unit in macrocycle provides a fixed chiral source, while 1,4-alkoxybenzene segments flip quickly to change their arrangement, which could provide reversible conformational chirality for those macrocycles. This rare example of macrocycles holding both fixed and conformational chirality lays a good foundation for expanding pillararenes using the fixed chiral source.