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Ligand‐Dependent Diastereoselectivity in the Palladium‐Catalyzed Copolymerization of Styrene with Carbon Monoxide
Author(s) -
Gsponer Achim,
Schmid Thomas M.,
Consiglio Giambattista
Publication year - 2001
Publication title -
helvetica chimica acta
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.74
H-Index - 82
eISSN - 1522-2675
pISSN - 0018-019X
DOI - 10.1002/1522-2675(20011017)84:10<2986::aid-hlca2986>3.0.co;2-r
Subject(s) - chemistry , copolymer , carbon monoxide , ligand (biochemistry) , olefin fiber , styrene , palladium , moiety , polymer chemistry , coordination sphere , regioselectivity , catalysis , chelation , medicinal chemistry , stereochemistry , organic chemistry , crystal structure , biochemistry , polymer , receptor
[(LL′)Pd(H 2 O)](OTf) 2 complexes, in which LL′ is a chelate ligand containing the chiral 4‐benzyl‐4,5‐dihydrooxazole moiety and either pyridin‐2‐yl or 2‐(diphenylphosphino)phenyl substituents, catalyze the copolymerization of styrene with carbon monoxide with an isotactic or prevailingly syndiotactic microstructure, respectively. The chiroptical properties of the copolymers and model studies for carbon monoxide and olefin insertion on related Pd complexes suggest that the reason for the different stereochemistry of the copolymers is a site‐selective coordination of the olefin in the intermediates containing the PN ligand; a lower regioselectivity in the coordination and a different coordination site lead to the different diastereoselectivity for the copolymer formation by the complex containing the NN′‐ligand.