Ugi Reactions with CO₂: Access to Functionalized Polyurethanes, Polycarbonates, Polyamides, and Polyhydantoins

Abstract

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.

Potentially biocompatible polyacrylamides derived by the Ugi four-component reaction

“…Acrylic acid 1 (99%, Aldrich) was freshly distilled before use in Ugi-4CRs. Methyl 4-isocyanobutyrate 4d was synthesized according a procedure mentioned in several publications [40][41][42][43][44][45]. All solvents were used without any kind of purification.…”

“…The Ugi-4CR further provided a strategy for the efficient conjugation of two types of polymers to either a fluorescent molecule, chemical agent or protein [37,38]. With regard to the monomer synthesis, the Ugi-4CR allowed the preparation of polymers with polypeptide-like features [39], a-amide substituted polyamides [40], convertible polyamides [41], and polyurethanes [42].…”

Application of named reactions in polymer synthesis

“…Ugi-5CC of 1,12-diaminododecane, isobutyraldehyde, tertbutyl isocyanide, carbon dioxide, and an alcohol leading to substituted dicarbamates [93].…”

“…For this purpose, 1,12-diaminododecane and 1,6-diisocyanohexane, together with isobutyraldehyde, methanol, and CO 2 , were used by Meier's group [93] to directly synthesize polyamides by Meier's group (Scheme 26). By varying the reaction conditions, the corresponding polyamides bearing methyl carbamate sidechains showed remarkable M n values of 20.2 kDa with polydispersity of 1.71.…”

The Ugi reaction in polymer chemistry: syntheses, applications and perspectives

“…Those results are complementary to Meier's results, broadening the synthetic scope of Ugi reaction in polycondensation. following the polycondensation process 60 . This approach offers a novel route for the incorporation of carbon dioxide into polymers and enable the synthesis of different structural motifs, such as polyurethanes and polyhydantoins in a catalyst-free fashion, paving a new way for a new class of polymers which might not be achievable by other MCRs in a straightforward way.…”