Facile, Rapid, and High-Yield Synthesis of Pillar5arene from Commercially Available Reagents and Its X-ray Crystal Structure

We monitored the progress of formation of dimethoxypillar5arene by size-exclusion chromatography. Surprisingly, the cyclization reaction completely finished in just 3 min. By improving the reaction conditions and purification process, we successfully obtained dimethoxypillar5arene in a short time and in high yield (71%) from commercially available reagents. By improving the deprotection reaction of the methoxy moieties, pillar5arene was isolated quantitatively. Single crystal X-ray analysis confirmed the structure of pillar5arene in the solid state.