Discrete multifunctional sequence-defined oligomers with controlled chirality

Discrete sequence-defined oligomers are synthetic mimics of short peptides, with possible applications in catalysis, information storage, drug delivery or self-assembly. Here, we report on the efficient and stereocontrolled synthesis of sequence-defined poly(triazole-urethane) oligomers incorporating a very large range of functional side groups, including alkyl, phenyl, pyridyl, hydroxyl, amine, imidazole and carboxylic acid functions. The route involves the alternation of chloroformate-mediated carbamate bond formation and Cu-catalyzed azide-alkyne cycloaddition reactions, expeditiously leading to oligomers up to octamers by an iterative exponential growth strategy. Additionally, the chirality of the monomers is straightforwardly controlled and maintained during the elongation process, leading to optically-active multifunctional oligomers of controlled molecular configuration, as confirmed by(1)H NMR, ESI-MS/MS and circular dichroism. Our strategy provides a versatile platform to efficiently synthesize discrete oligomers with programmable stereochemistry, sequentiality and multifunctionality.