5,5-Dialkyldipyrromethane as a precursor for the synthesis of calix[4]phyrins and pseudocorroles using MacDonald [2+2] condensations

The reaction of formylated dialkyldipyrromethanes with 5,5-dialkyl or 5-aryldipyrromethanes afforded meso-tetraalkyl or dialkylaryl-calix[4]phyrins, respectively. Templating with Ni(II) was needed to get these compounds in acceptable yields. From these MacDonald condensations, trisubstituted pseudocorroles were also isolated as Ni(II) chelates.