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Systematic Study of the Asymmetric Methoxycarbonylation of Styrene Catalyzed by Palladium Systems Containing Chiral Ferrocenyl Diphosphine Ligands
Author(s) -
Godard Cyril,
Ruiz Aurora,
Claver Carmen
Publication year - 2006
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/hlca.200690161
Subject(s) - chemistry , phosphine , styrene , catalysis , regioselectivity , palladium , ligand (biochemistry) , ferrocene , enantiomeric excess , enantiomer , carbonylation , medicinal chemistry , organic chemistry , combinatorial chemistry , enantioselective synthesis , copolymer , electrochemistry , electrode , receptor , biochemistry , carbon monoxide , polymer
We present the first systematic study of the Pd‐catalyzed asymmetric methoxycarbonylation of styrene in the presence of chiral ferrocenyl phosphine ligands. The reaction conditions were optimized, and a screening of different catalyst precursors was performed. A number of 1,1′‐bis(phosphino)ferrocenes of the Mandyphos, Josiphos, Walphos , and Taniaphos types were tested in combination with [PdCl 2 (NCPh) 2 ], in the presence of TsOH as the acid source. These systems afforded high enantioselectivities, although the regioselectivity of the reaction was found to be in favor of the (undesired) linear ester. The catalytic system made with the Josiphos ligand 1 gave rise to an enantiomeric excess (ee) of 86%.