Novel β-substituted calix[4]pyrroles

Calix[4]pyrroles have attracted considerable attention within the macrocyclic, supramolecular, and porphyrin analog communities due to their ability to act as simple-to-synthesize receptors for common anions, such as chloride and fluoride. Reported here is what we believe is a new, potentially generalizable route to fully beta-alkyl substituted calixpyrroles. These products are accessible from the starting pyrrolic esters, and are obtained via simple reaction with CH3Li, followed by subsequent quenching with HCl in ether. A representative system has been characterized by X-ray diffraction analysis. The present route allows access to calix[4] pyrroles bearing functionality, such as double bonds, off the so-called C-rim; such systems are of interest because they could allow for further synthetic elaborations and permit incorporation of calix[4] pyrroles into more complex structures.