697-63-2Relevant academic research and scientific papers
Efficient Ru(II)-catalyzed asymmetric hydrogenation of simple ketones with C2-symmetric planar chiral metallocenyl phosphinooxazoline ligands
Guo, Hui,Liu, Delong,Butt, Nicholas A.,Liu, Yangang,Zhang, Wanbin
, p. 3295 - 3299 (2012)
C2-symmetric metallocenyl planar phosphinooxazoline ligands (2 and 3) have been applied in the Ru(II)-catalyzed asymmetric hydrogenation of simple ketones. This type of ligands enjoys the advantages of dual reaction sites as well as larger steric hindrance than their corresponding C 1-symmetric counterparts. As a result, almost quantitative conversions and excellent enantioselectivities were obtained for a series of simple ketones. Under the optimal reaction conditions, up to 99.7% ee was obtained in many cases. It was also confirmed that hydrogen rather than reaction solvent i-PrOH is at work in the hydrogenation procedure.
Asymmetric transfer hydrogenation of prochiral ketones in aqueous media with new water-soluble chiral vicinal diamine as ligand
Ma, Yaping,Liu, Hui,Chen, Li,Cui, Xin,Zhu, Jin,Deng, Jingen
, p. 2103 - 2106 (2007/10/03)
(Matrix presented) An easily accessible water-soluble chiral o-sulfonated 1,2-diphenylethlenediamine 2 and its mono-N-tosylated derivative 3 were synthesized for the first time. The ruthenium-complex-catalyzed reduction of prochiral ketones in aqueous media has been examined by using 3 as ligand and sodium formate as the source of hydrogen. The asymmetric transfer hydrogenation of ω-bromo acetophenones was achieved, in which only formate displacement occurred when formic acid/triethylamine azeotrope was used as the hydrogen donor.
Synthesis and catalytic reactivity of D4-symmetric dinorbornabenzene-derived metallotetraarylporphyrins
Halterman, Ronald L.,Jan, Shyi-Tai,Nimmons, Heather L.,Standlee, David J.,Khan, Masood A.
, p. 11257 - 11276 (2007/10/03)
The condensation of the resolved C2-symmetric benzaldehyde, 1,2,3,4,5,6,7,8-octahydro-1:4,5: 8-dimethanoanthracene-9-carboxyaldehyde, with pyrrole produced the first chiral tetraarylporphyrin 1 exhibiting D4-symmetry. The resolved benzaldehyde was synthesized in seven steps from p-benzoquinone and cyclopentadiene and included a resolution via diastereomeric ketals. A manganese chloride complex of porphyrin 1 was used as a catalyst for the asymmetric epoxidation of aromatic substituted alkenes in the presence of excess sodium hypochlorite in up to 7,200 turnovers and up to 76% e.e and >90% yield.
Lithium Aluminium Hydride Partially Decomposed with (-)-N-Methylephedrine and 2-Alkylaminopyridine: An Improved Chiral Hydride Useful for the Practical Asymmetric Reduction of Achiral Cyclic Ketones
Kawasaki, Motoji,Suzuki, Yasutaka,Terashima, Shiro
, p. 52 - 60 (2007/10/02)
The title chiral hydride was found to reduce various achiral cyclic ketons, giving the corresponding optically active cyclic (R)-alcohols in high optical (73-98percent) yields.The development of the improved chiral hydride and some characteristics of the reagent are also described.Keywords - asymmetric reduction; lithium aluminium hydride; (-)-N-methylephedrine; 2-alkylaminopyridine; 2-cyclohexen-1-one; achiral cyclic ketone; optically active cyclic alcohol
