Clickity-click: highly functionalized peptoid oligomers generated by sequential conjugation reactions on solid-phase support

N-Substituted glycine peptoid oligomers were used as substrates for azide-alkyne [ 3 + 2] cycloaddition conjugation reactions and then elaborated through additional rounds of oligomerization and cycloaddition. This novel sequential conjugation technique allowed for the generation of complex peptidomimetic products in which multiple heterogeneous pendant groups were site-specifically positioned along the oligomer scaffold. Studies of a water-soluble estradiol-ferrocene peptoid conjugate demonstrated a potential application for the modular synthesis of biosensors.