Selective Synthesis of Hetero-Sequenced Aza-Cyclophanes

The selective synthesis of purely organic cages with hetero-sequenced functionalized cavities is demonstrated. The strategy to obtain these compounds is based on a stepwise approach using thermodynamically controlled imine condensations. To accomplish this, the amine building blocks carry additional azide groups, which act as masked amines and enable the synthesis of the desired cavities. This approach offers a precise control of interior functionalization, the substitution pattern and the cage size, which is demonstrated by the selective synthesis of four cages. The largest described cage has been investigated towards its ability for guest encapsulation and is able to selectively encapsulate functionalized arenes that offer a matching substitution pattern.