Efficient NMR Enantiodifferentiation of Chiral Quats with BINPHAT Anion
摘要:
[GRAPHICS]Hexacoordinated phosphorus BINPHAT anion is an efficient NMR chiral shift agent for quaternary ammonium cations (quats) leading to large separations (DeltaDeltadelta up to 0.29 ppm) of the proton signals of the enantiomers.
Design, Synthesis, and Application of a C2 Symmetric Chiral Ligand for Enantioselective Conjugate Addition of Organolithium to α,β-Unsaturated Aldimine
摘要:
A C-2 symmetric chiral diether ligand, (1R,2R)-1,2-dimethoxy-1,2-diphenylethane was designed and synthesized on the basis of the concept of an asymmetric oxygen atom. Mediated by the chiral diether, high enantioselectivities were achieved in conjugate addition of organolithiums to naphthaldehyde imine and cyclic and acyclic alpha,beta-unsaturated aldimines. The absolute configuration of the product is predictable by the model.
To realize polarization change in non-ferroelectric crystals, valencetautomeric (VT) complexes with polar crystal structure were synthesized based on our strategy, i. e. introduction of enantiopure ligand into the metal complexes exhibiting intramolecular electron transfer. The VT transition is accompanied by the change in molecular dipole moment. Because the net polarization of the polar crystal