Enantioselective Hydrogenation of α,β-Unsaturated Cyclic Ketones by Double Asymmetric Induction Preparation of (R)-Muscone

By ketal formation with chiral glycols like methyl or ethyl ester of tartaric acid,hydrogenation of ketals from the correspondingα,β-unsaturated 15-membered cyclic ketone produces (R)-muscone in good chemical and optical yield in the presence of chiral catalysts

Asymmetric Induction of Chiral 1,1'-Bis(oxazolinyl)ferrocenes as Ligands in Metal-Catalyzed Cyclopropanation and Diels-Alder Reactions

Four chiral 1,1?bis(oxazolinyl)ferrocenes(1a-1d) have been prepared and used as ligands in the copper catalyzed asymmetric cyclopropanation of styrene with ethyl diazoacetate (EDA) and the magnesium catalyzed Diels-Alder reaction between 3-acryloyl-2-oxazolidinone and cyclopentadiene. Enantioselectivities up to 24% and 41%, respectively, for cyclopropanation and Diels-Alder reaction were observed.

ASYMMETRIC SYNTHESIS Ⅻ:HIGHLY ENANTIOSELECTIVE SYNTHESIS OF α-AMINO ACIDS BY ALKYLATION OF THE KETIMINE FROM 2-HYDROXY-PINAN-3-ONE AND MENTHYL GLYCIN-ATE A DOUBLE ASYMMETRIC INDUCTION SYSTEM

A series of α-amino acids are obtained in 72-96% optical yields by alkylation of the ketimine derived from(+)-2-hydroxy-pinan-3-one and(-)-menthyl glycinate fol- lowed by hydrolysis of the alkylated intermediates with mineral acid.The double asymmetric induction are explained by the transition model of lithium enolate.

A New Switching Sequences of SVPWM for Six-Phase Induction Motor with Features of Reduced Switching Losses

In this paper,new SVPWM switching sequences for six-phase asymmetrical induction motor drives are derived with the aim to reduce inverter’s switching losses.Total three switching sequences are introduced in this paper.These sequences are derived such that the phases get continuously clamped when a current of the phases is around its peak magnitude and hence reduced switching losses are recorded.The comparative performances of these modulation techniques are studied with two existing switching sequences.Simulation,analytical and experimental results are presented.Based on these results,it is found that new switching sequences reduce switching losses effectively in dual three phase inverters.

A Chiral Phosphorous Derivatizing Agent for the Determination of the Enantiomeric Excess of Chiral Alcohols, Amines by ^(31)P NMR

A chiral phosphorous derivatizing agent prepared from PCl3 and (S)-BINOL was described. It is used to determine the enantiomeric excess of chiral alcohols and amines by 31P NMR.

1,6-Asymmetric induction: a higher enantioselective synthesis of γ-butyrolactone

A novel 1,6-asymmetric induction has been observed in the iodolactonization of γ,δ-unsa- turated amides. The optically active γ-butyrolactone was synthesized by employing iodolactonization reaction as a key step.