A novel strategy is demonstrated to obtain polyamides with finely tunable structure using the Ugi fourcomponent reaction (Ugi-4CR). By the use of two bifunctional and two monofunctional components, six different combinations for the synthesis of polyamides via the Ugi-4CR are possible and were investigated in detail within this contribution. In contrast to conventional polyamide synthesis, this approach proceeds under very mild reaction conditions and without the use of a catalyst in a one-pot reaction. General applicability is shown by variation of the components, leading to finely tuned macromolecular structures (i.e., side groups and repeat units can be engineered). Finally, a facile introduction of clickable alkyne moieties is demonstrated, which was used for post-polymerization modification in an azide−alkyne cycloaddition, in order to demonstrate the high versatility of this approach.

The combination of the Ugi four-component reaction (Ugi-4CR) with acyclic diene metathesis (ADMET) or thiol-ene polymerization led to the formation of poly-1-(alkylcarbamoyl) carboxamides, a new class of substituted polyamides with amide moieties in the polymer backbone, as well as its side chains. 10-Undecenoic acid, obtained by pyrolysis of ricinoleic acid, the main fatty acid of castor oil, was used as the key renewable building block. The use of different primary amines, as well as isonitriles (isocyanides) for the described Ugi reactions provided monomers with high structural diversity. Furthermore, the possibility of versatile post-modification of functional groups in the side chains of the corresponding polymers should be of considerable interest in materials science. The obtained monomers were polymerized by ADMET, as well as thiol-ene, chemistry and all polymers were fully characterized. Finally, ortho-nitrobenzylamide-containing polyamides obtained by this route were shown to be photoresponsive and exhibited a dramatic change of their properties upon irradiation with light.

A new strategy to obtain functionalized acrylate monomers is introduced using the Passerini three-component reaction (Passerini-3CR). This straightforward one-pot synthesis is characterized by excellent atom economy and structurally diverse products. By using acrylic acid and a variety of aldehydes and isocyanides, a set of several acrylate monomers was synthesized. Subsequent free radical polymerization yielded polyacrylates with tunable properties depending on the used components for the Passerini reaction. For instance, by varying the aldehyde component from acetaldehyde to heptanal, control over the glass transition in the final polymer was achieved. Moreover, for highly polar acrylate monomers a thermoresponsive behavior (upper critical solution temperature; UCST) was observed in methanol and/or ethanol.

A novel strategy for the incorporation of carbon dioxide into polymers is introduced. For this purpose, the Ugi five-component condensation (Ugi-5CC) of an alcohol, CO2 , an amine, an aldehyde, and an isocyanide is used to obtain step-growth monomers. Polymerization via thiol-ene reaction or polycondensation with diphenyl carbonate gives diversely substituted polyurethanes or alternating polyurethane-polycarbonates, respectively. Furthermore, the application of 1,12-diaminododecane and 1,6-diisocyanohexane as bifunctional components in the Ugi-5CC directly results in the corresponding polyamide bearing methyl carbamate side chains (M¯n = 19 850 g mol(-1) ). The latter polymer is further converted into the corresponding polyhydantoin in a highly straightforward fashion.

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Poly(2-oxazoline)s are receiving large current interest based on their potential use in biomedical applications. Here we report a novel, straightforward route towards functional poly(2-oxazoline)s by Passerini and Ugi reactions.

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Palladium nanoparticles stabilized by poly(vinylpyrrolidone) catalyze Tsuji-Trost allylations in water with very high turnover numbers. The di-allylation of methylene active compounds and the allylation of bio-based phenols was performed in high yield. The allylation of lignin showed a high selectivity towards the phenolic OH groups.