Synthesis of upper rim N-formamido and isocyanocalix[4]arenes: adaptation of Ugi-4-CR on calix[4]arenes towards peptide-like architectures

Methods are described for the selective diametrical functionalization of calix[4]arenes at the upper rim by formamide and isocyanide functional groups. The adaptation of Ugi-4-CR to calix[4]arenes leading to α-acylaminocarboxamide derivatives is also discussed.