174390-40-0Relevant academic research and scientific papers
ASYMMETRIC CATALYTIC HYDROGENATION OF PROCHIRAL KETONES AND ALDEHYDES
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Page/Page column 27, (2010/11/28)
Process for stereoselective hydrogenation by reacting racemic aldehydes or ketones having a stereogenic carbon atom in the position relative to the C(O) group and containing the structural element -(O)C-C-CH- by means of hydrogen in the presence of a base and a ruthenium complex containing a bidentate ligand having coordinating P and N atoms, a monophosphine ligand and anionic and/or uncharged ligands as homogeneous catalyst, with the charge being balanced by one or two monovalent acid anions or a divalent acid anion when uncharged ligands are present.
trans-RuH(η1-BH4)(binap)(1,2-diamine): A catalyst for asymmetric hydrogenation of simple ketones under base-free conditions
Ohkuma, Takeshi,Koizumi, Masatoshi,Muniz, Kilian,Hilt, Gerhard,Kabuto, Chizuko,Noyori, Ryoji
, p. 6508 - 6509 (2007/10/03)
(Chemical Equqtion Presentation) Reaction of a chiral RuCl2(diphosphine)(1,2-diamine) complex and NaBH4 forms trans-RuH(η1-BH4)(diphosphine)(1,2-diamine) quantitatively. The TolBINAP/DPEN Ru complex has been characterized by single crystal X-ray analysis as well as NMR and IR spectra. The new Ru complexes allow for asymmetric hydrogenation of simple ketones in 2-propanol without an additional strong base. Various base-sensitive ketones are convertible to chiral alcohols in a high enantiomeric purity with a substrate/catalyst ratio of up to 100 000 under mild conditions. Configurationally unstable 2-isopropyl- and 2-methoxycyclohexanone can be kinetically resolved with a high enantiomer discrimination. This procedure overcomes the drawback of an earlier method using RuCl2(diphosphine)(diamine) and an alkaline base, which sometimes causes undesired reactions such as ester exchange, epoxy-ring opening, β-elimination, and polymerization of ketonic substrates. Copyright
Hydrogenation of α-Keto Ethers: Dynamic Kinetic Resolution with a Heterogeneous Modified Catalyst and a Heterogeneous Base
Studer, Martin,Blaser, Hans-Ulrich,Burkhardt, Stephan
, p. 511 - 515 (2007/10/03)
The first successful example of the asymmetric hydrogenation of substituted α-keto ethers with Cinchona-modified Pt/Al2O3 is reported. In the absence of an additional base, kinetic resolution of the racemic starting material was observed with high diastereoselectivity and ee's up to 98% at conversions of a strong reaction acceleration but racemic product. Immobilization of OH- on solid ion exchangers resulted in the desired dynamic kinetic resolution, and ee's of >80% were obtained at >95% conversion. These effects are rationalized on the basis of a simple kinetic and structural model.
Diastereoselective synthesis of a key intermediate for the preparation of tricyclic β-lactam antibiotics
Matsumoto, Takaji,Murayama, Toshiyuki,Mitsuhashi, Shigeru,Miura, Takashi
, p. 5043 - 5046 (2007/10/03)
Asymmetric synthesis of (S)-5 has been accomplished with an excellent enantiomeric excess by hydrogenation of racemic 5 using ruthenium-BINAP- diamine-KOH system, followed by oxidation. Magnesium enolate of (2S)-2- methoxycyclohexanone [(S)-5] reacts with
Process for preparing optically active cyclohexanol derivatives
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, (2008/06/13)
A process for producing an optically active cyclohexanol derivative represented by formula (I): STR1 wherein R1 represents an alkyl group having 1 to 4 carbon atoms, a hydroxyl group, or a protected hydroxyl group, comprising asymmetrically hyd
