ATH reductions of aliphaticketones in water catalyzed by ruthenium coordinated by prolinamide ligands produce alcohols with moderate enantiomeric excesses in most cases. A set of seven aliphaticketones is proposed for a rapid evaluation of the enantioselectivity of catalysts by one-pot multi-substrates reduction. The screening of a library of prolinamides shows that according to the structure of
Asymmetric reduction of aliphatic ketones and acyl silanes using chiral anti-pentane-2,4-diol and a catalytic amount of 2,4-dinitrobenzenesulfonic acid
Aliphatic ketones were reduced to the corresponding secondaryalcohols by using anti-1,3-diol and a catalytic amount of 2,4-dinitrobenzenesulfonic acid (DNBSA) in benzene at reflux. Addition of 1-octanethiol in that media improved the efficiency of the reduction. Asymmetric reduction of aliphatic ketones was performed by using chiral anti-pentane-2,4-diol, and highly asymmetric induction (up to >99%
New chiral borohydrides. 3. Preparation and asymmetric reducing properties of potassium 9-O -(1,2-isopropylidene-5-deoxy-α-D-xylofuranosyl)-9-borata-bicyclo[3.3.1]nonane
作者:Byung Tae Cho、Yu Sung Chun
DOI:10.1016/s0957-4166(00)82314-9
日期:1992.1
A stable, new chiralborohydride, potassium 9-O- (1,2-O-isopropylidene-5- deoxy-α-D-xylofuranosyl)-9-boratabicyclo[3.3.1]nonane (K xylide,1D) using a xylose derivative as a chiralauxiliary was prepared by the treatment of the corresponding borinic ester3D with potassium hydride in THF. The reagent provided high optical induction for asymmetricreduction of prochiral ketones, such as relatively hindered
Amino Acid Mediated Borane Reduction of Ketones IIa
作者:Aleksandar V. Teodorović、Milan D. Joksović、Ivan Gutman、Željko Tomović
DOI:10.1007/s007060270003
日期:2002.1
alcohols of ( R )-configuration ( ee = 23–89%). A molecular topology based model was developed for describing the influence of the substituents, both in the oxazaborolidine type reagent and in the ketone, on the observed chiral induction.
苯乙酮,2,2-二甲基环戊酮,3,3-二甲基-2-丁酮,3-甲基-2-丁酮和2-戊酮被( S )-丙氨酸,( S )-蛋氨酸,( S )-亮氨酸,( S )-缬氨酸和( S )-异亮氨酸, 收率很高,主要产生( R )-构型的醇 ( ee = 23–89%)。建立了基于分子拓扑的模型,用于描述恶唑硼烷型试剂和酮中取代基对观察到的手性诱导的影响。
Asymmetric Hydrogenation of<i>tert</i>-Alkyl Ketones: DMSO Effect in Unification of Stereoisomeric Ruthenium Complexes
Face off: The rutheniumcomplexes of a new axially chiral PNN ligand (L) are highly efficient in the presence of dimethylsulfoxide (DMSO) for hydrogenation of both functionalized and unfunctionalized tert‐alkyl ketones. DMSO is thought to narrow down the many possible complex stereoisomers into a single facial L/Ru complex, thus enhancing the reactivity, selectivity, and productivity.