Narrow-rim functionalization of calix[4]arene through Ugi-4CR: synthesis of a series of calix[4]arene peptoids.

Adaptation of Ugi-4CR for the narrow-rim modification of calix[4]arene toward the synthesis of a series of tripeptoid and tetrapeptoid calix[4]arenes is described. The metal ion/organic cation binding properties of the newly synthesized peptoid calix[4]arenes were also investigated.