Enantioselective Synthetic Reactions using Chiral Lithium Amide Bases

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Studies using deuterated cyclohexanone derivatives determined the protons that are selectively deprotonated in the asymmetric deprotonation reactionsThe stereochemistry of the asymmetric alpha-alkylation of cyclic ketones was clarified on the basis of the reactions with 4-substituted cyclohexanonesAsymmetric protonation of achiral enolates was achieved, based on which the method to convert racemic ketones into optically active ones was established. Studiesusing deuterated compounds clarified that this protonation proceeded through protonation of chiral aminesThe solution structures of three chiral lithium amides were determined by ^6Li and ^<15>N-NMR spectroscopy, and their crystal structures were determined by X-ray analysis. The solution structure (agregation state) was able to be controlled by strong external ligands. The relationship between these results and the actual reactions was clarified.The asymmetric deprotonation reactions described above were extended to catalytic asymmetric reactions, the mechanism of which was proposedCatalytic asymmetric alkylation was successfully achieved with high efficiency. The mechanistic study is in progress.Asymmetric aldol and Darzens reactions using chiral bases were achieved