Optically Active Helical Poly(phenyl isocyanide)s Bearing Achiral Benzanilide Pendants: from Controlled Synthesis to Enantioseparation Application

The helical structures found in biological systems, such as DNA, have inspired significant research interest in artificial helical polymers, owing to their strong potential for applications including chiral recognition and resolution, asymmetric catalysis, and other related areas. However, the preparation of single-handed helices from achiral starting materials, as well as the exploration of their chiral resolution behavior, continues to represent a considerable challenge. In this work, we present the rational design and synthesis of optically active helical poly(phenyl isocyanide)s through helix-sense selective polymerization (HSSP) of achiral phenyl isocyanide monomers, catalyzed by enantiopure Pd(II) complexes bearing S - or R -configured ligands (Pd(II)/L S or L R ). The polymerization exhibits living and controlled characteristics, allowing for the precise modulation of molecular weights ( M n ) with exceptionally narrow distributions ( M w / M n ). The resulting polymers exhibit intense optical activity and demonstrate outstanding performance in chiral recognition. Specifically, these chiral materials are utilized as a chiral stationary phase (CSP), which can separate various racemates including α -methylbenzylamine, cobaltic acetylacetonate, and 2-hydroxy-2-phenylacetophenone. Additionally, when applied as a chiral crystallization agent, the polymer enabled the resolution of racemic Z -Alanine via enantioselective crystallization, yielding an enantiomeric excess ( ee ) as high as 81%.