NMR studies on the structure of a lithium amide–chiral diether complex for an asymmetric reaction
摘要:
The combination of a chiral diether ligand and a lithium benzyl(trimethylsilyl)amide is a powerful lithium amide reagent for asymmetric conjugate amination of enoate in a toluene solvent. The structure of the chiral diether-lithium amide complex in solution was analyzed by low-temperature NMR. Li-6 NMR suggested the formation of a cyclic heterodimer. The stereochemical pathway is predictable based on the structure of the lithium amide chiral diether complex. (C) 2013 Elsevier Ltd. All rights reserved.