A Column Chromatography-Free Protocol for the Synthesis of Water-Soluble Cavitands

An efficient synthetic protocol for the synthesis of a library of unprecedented resorcin[4]arene-based water-soluble molecular containers is reported here. Key to this approach is the tetra-iodo derivative 3, named "Key Iodo Cavitand" (KIC), which acts as a concave-shaped scaffold for the synthesis of deep-cavitands via Sonogashira coupling. Most of the deep-cavitands described in this study are synthesized without chromatographic processes, leading to a faster purification, ready accessibility, and easier scale-up, while also offering a different cavity in terms of size and shape compared to the current ones. Preliminary binding experiments on cyclodecane as a model guest are reported in D₂O, while DFT calculations confirm the encapsulation of fullerene derivatives such as C₆₀ and C₇₀, highlighting the potential of the proposed molecular containers.