Synthesis and Biodegradability of Tartaric Acid-Based Poly(ester-thioether)s via Thiol–Ene Click Polymerization

[Image: see text] Using scandium triflate [Sc(OTf)(3)] as a catalyst, chemoselective esterification of tartaric acids by 3-butene-1-ol was performed, and we produced three dialkene monomers: l-di(3-butenyl) tartrate (BTA), d-BTA, and meso-BTA. Thiol–ene polyaddition of these dialkenyl tartrates and dithiols including 1,2-ethanedithiol (ED), ethylene bis(thioglycolate) (EBTG), and d,l-dithiothreitol (DTT) proceeded in toluene at 70 °C under nitrogen to give tartrate-containing poly(ester-thioether)s (M(n), (4.2–9.0) × 10(3); molecular weight distribution (M(w)/M(n)), 1.6–2.5). In differential scanning calorimetry, the poly(ester-thioether)s showed single T(g)s between −25 and −8 °C. In biochemical oxygen demand (BOD) tests using activated sludge, poly(l-BTA-alt-EBTG) and poly(l-BTA-alt-ED) showed 32 and 8% biodegradability, which is comparable to that of similar l-malate-containing poly(ester-thioether)s (23 and 13% biodegradation, respectively). Notably, we observed enantio and diastereo effects on biodegradation because poly(l-BTA-alt-EBTG), poly(d-BTA-alt-EBTG), and poly(meso-BTA-alt- EBTG) showed different degradation behaviors during the biodegradation test (BOD/theoretical oxygen demand (TOD) values after 28 days, 32, 70, and 43%, respectively). Our findings provide insights into the design of biomass-based biodegradable polymers containing chiral centers.