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Screening of a Modular Sugar‐Based Phosphite–Oxazoline Ligand Library in Asymmetric Pd‐Catalyzed Heck Reactions
Author(s) -
Mata Yvette,
Pàmies Oscar,
Diéguez Montserrat
Publication year - 2007
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.200601714
Subject(s) - oxazoline , chemistry , ligand (biochemistry) , heck reaction , catalysis , moiety , palladium , axial chirality , microwave irradiation , organic chemistry , combinatorial chemistry , enantioselective synthesis , biochemistry , receptor
We have synthesised a library of phosphite–oxazoline ligands derived from readily available D ‐glucosamine. These ligands have been successfully screened in the palladium‐catalysed Heck reaction of several substrates with high regio‐ (up to 99 %) and enantioselectivities ( ee 's up to 99 %) as well as with improved activities under standard thermal conditions. The results indicate that the catalytic performance is highly affected by the oxazoline and biarylphosphite substituents and the axial chirality of the biaryl moiety of the ligand. The Heck reactions were also performed under microwave irradiation conditions, allowing a considerably shorter reaction time (full conversion in minutes) maintaining the excellent regio‐ and enantioselectivities.