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DOI: 10.1055/a-2601-5358
Helically Chiral Polyquinoxaline Carboxylates Bearing Achiral Ar3P for Asymmetric Suzuki Coupling in Water
Single-Handed Helical Polymer-Based Polycarboxylate with Achiral Triarylphosphine Pendants as Chiral Catalysts for Asymmetric Cross-Coupling Reactions in Pure Water.
J. Am. Chem. Soc. 2025;
147: 8534-8547
DOI: 10.1021/jacs.4c16952
Keywords
asymmetric catalysis - chiral helix - palladium - phosphine ligand - polyquinoxaline - Suzuki coupling - binaphthyls
Significance
A helically chiral polymer-based triarylphosphine ligand (S)-PQXPhos-COOH, bearing a hydrophobic helical interior and a hydrophilic carboxylate exterior, was prepared through quinoxaline-forming co-polymerization of (S)-1-COOEt and biaryl 2. Palladium-catalyzed cross-coupling of compounds 3 and 4 took place at 40 °C in the presence of (S)-PQXPhos-COOH in water to give a 90 % yield of (S)-5 with 99 % enantioselectivity.
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Comment
(R)-PQXPhos-C2H5 , which lacks a hydrophilic exterior, exhibited lower catalytic performance in aqueous THF (42 % yield, 94 % ee) and extremely low activity in pure water (4 % yield). The (S)-PQXPhos-COOH/Pd/water system afforded a variety of axially chiral binaphthyls, naphthylbenzenes and naphthylpyrene with excellent enantioselectivities.
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Publikationsverlauf
Artikel online veröffentlicht:
23. Juni 2025
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