Facile access to modified and functionalized PNAs through Ugi-based solid phase oligomerization.

Peptide nucleic acids (PNAs) derivatized with functional molecules are increasingly used in diverse biosupramolecular applications. PNAs have proven to be highly tolerant to modifications and different applications benefit from the use of modified PNAs, in particular modifications at the γ position. Herein we report simple protocols to access modified PNAs from iterative Ugi couplings which allow modular modifications at the α, β or γ position of the PNA backbone from simple starting materials. We demonstrate the utility of the method with the synthesis of several bioactive small molecules (a peptide ligand, a kinase inhibitor and a glycan)-PNA conjugates.