ABSTRACT
Association of enantiopure TRISPHAT anion (1) with chiral spiro [Cu(LL')2] complexes (LL' = 2-R-phen, 2, 6-R-bpy, 3, and 2-iminopyridine, 4) leads to an efficient NMR enantiodifferentiation. Variable temperature 1H NMR spectroscopy has been used to determine the isomerisation kinetics of these pseudo-tetrahedral complexes and to evaluate their configurational stability; the latter depending on the structure of the diimine ligands. In the case of the 2-anthracenyl-phen derivative, a decent level of supramolecular stereocontrol was noted (d.e. up to 45%); the configuration of the complex being determined by electronic circular dichroism (ECD).
ABSTRACT
By associating chiral labile [FeL3](2+) complexes with TRISPHAT anions, a stereocontrol of the metal-centered chirality is feasible; the sense of the stereoselective induction and its magnitude strongly depends upon the structure of the diimine ligands (L: bpy, phen).
ABSTRACT
Mannose derived hexacoordinated phosphate--prepared in two steps from methyl-alpha-D-mannopyranoside--is a chiral anionic auxiliary with broad asymmetric efficiency.
Subject(s)
Anions/chemical synthesis , Mannosephosphates/chemical synthesis , Methylmannosides/chemical synthesis , Anions/chemistry , Magnetic Resonance Spectroscopy , Mannosephosphates/chemistry , Methylmannosides/chemistry , Models, Molecular , Molecular Structure , Oxidation-Reduction , StereoisomerismABSTRACT
Two configurationally stable, chiral anions (TRISPHAT, 1) behave as efficient hosts that control the configuration of a configurationally labile iron(II) complex as the guest with high diastereoselectivity (>96 % de) upon ion pairing. The diastereoselectivity increases with decreasing solvent polarity.
