title: Sugar-Annulated Oxazoline Ligands: A Novel Pd(II) Complex and Its Application in Allylic Substitution.
abstract: Two novel carbohydrate-derived pyridyl (PYOX)- and cyclopropyl (CYBOX)-substituted oxazoline ligands were prepared from d-glucosamine hydrochloride and 1,3,4,6-tetra-O-acetyl-2-amino-2-deoxy-β-d-glucopyranose hydrochloride in two steps, respectively. The sugar-annulated PYOX ligand formed a stable metal complex with Pd(II), which was fully characterized by NMR spectroscopy and X-ray crystallography. NMR and X-ray analysis revealed a change of the conformation in the sugar moiety upon complexation with the palladium(II) species. Both glycosylated ligands resulted in high asymmetric induction (up to 98%ee) upon application as chiral ligands in the Pd-catalyzed allylic alkylation ofrac-1,3-diphenylallyl acetate with dimethyl malonate (Tsuji-Trost reaction). Both ligands provided mainly the (R)-enantiomer of the alkylation product.
authors.affiliation: Institute of Organic Chemistry, University of Tübingen, Auf der Morgenstelle 18, 72076 Tübingen, Germany. jochen.kraft@uni-tuebingen.de.
authors.forename: Jochen
authors.initials: J
authors.lastname: Kraft
authors.affiliation: Institute of Organic Chemistry, University of Tübingen, Auf der Morgenstelle 18, 72076 Tübingen, Germany. katharina.mill@student.uni-tuebingen.de.
authors.forename: Katharina
authors.initials: K
authors.lastname: Mill
authors.affiliation: Institute of Organic Chemistry, University of Tübingen, Auf der Morgenstelle 18, 72076 Tübingen, Germany. thomas.ziegler@uni-tuebingen.de.
authors.forename: Thomas
authors.initials: T
authors.lastname: Ziegler
mesh_terms: D000478:Alkylation; D002241:Carbohydrates / Q000737:chemistry*; D002384:Catalysis; D018360:Crystallography, X-Ray; D005944:Glucosamine / Q000031:analogs & derivatives* / Q000737:chemistry; D008024:Ligands; D008314:Malonates / Q000737:chemistry*; D008968:Molecular Conformation; D019906:Nuclear Magnetic Resonance, Biomolecular; D010080:Oxazoles / Q000138:chemical synthesis* / Q000737:chemistry; D010165:Palladium / Q000737:chemistry*
chemical_list: D002241:Carbohydrates; D008024:Ligands; D008314:Malonates; D010080:Oxazoles; D010165:Palladium; C005230:methyl malonate; D005944:Glucosamine
keywords: Tsuji-Trost; asymmetric catalysis; carbohydrates; oxazolines; palladium complexes; pyridines