Single-Handed Helical Polymer-Based Polycarboxylate with Achiral Triarylphosphine Pendants as Chiral Catalysts for Asymmetric Cross-Coupling Reactions in Pure Water.

Helical poly(quinoxaline-2,3-diyl)s (PQX) containing chiral carboxylic acid side chains derived from natural l-lactic acid were synthesized. The newly synthesized helical polycarboxylated polymer was soluble in basic pure water by forming polycarboxylate and adopted the -helical conformation (right-handed), whereas the -helical conformation is predominant under weakly acidic aqueous conditions. The water-soluble PQX containing additional monomer units bearing a 2-(diarylphosphino)phenyl group was employed in the asymmetric Suzuki-Miyaura coupling reaction in pure water in the absence of organic cosolvents.