Synthesis and thermo-responsive behavior of helical polyacetylenes derived from proline

A series of optically active helical poly[(S)-2-ethynyl-N-aliphatic acylpyrrolidine] were efficiently synthesized from a commercially available biomass-based starting material, and that bearing a short propionyl substituent exhibited an unexpected lower critical solution temperature in an aqueous solution with a narrow phase-transition window and a small hysteresis.