124150-23-8Relevant articles and documents
Enantioselective hydrogenation of β-keto esters catalyzed by P-chiral bis(dialkylphosphino)ethanes-Ru(II)
Yamano, Toru,Taya, Naohiro,Kawada, Mitsuru,Huang, Taisheng,Imamoto, Tsuneo
, p. 2577 - 2580 (1999)
Asymmetric hydrogenation of keto esters using a BisP*-RuBr2 catalyst is reported. High enantioselectivities up to 98% were achieved in the hydrogenation of β-keto esters.
(Diphenylphosphino)-biheteroaryls: the First Example of a New Class of Chiral Atropisomeric Chelating Diphosphine Ligands for Transition Metal Catalysed Stereoselective Reactions
Benincori, Tiziana,Brenna, Elisabetta,Sannicolo, Franco,Trimarco, Licia,Antognazza, Patrizia,Cesarotti, Edoardo
, p. 685 - 686 (1995)
Ruthenium(II) dichloride complexes with (+)- and (-)-2,2'-bis(diphenylphosphino)-4,4',6,6'-tetramethyl-3,3'-bibenzothiophene (1a), new chiral atropisomeric heterocyclic ligands, reduce α- and β-oxoesters to α- and β-hydroxyesters with an enantiomeric purity comparable, if not higher, to that reported for binap under the same experimental conditions.
Intramolecular Hydrosilylations of β,γ-Unsaturated Acyloxy Silanes. A Convenient Synthesis of (2S,3R)-N-BOC-3-Hydroxyproline Methyl Ester
Sibi, Mukund P.,Christensen, James W.
, p. 6213 - 6216 (1995)
A regio- and stereoselective synthesis of hydroxylated carboxylic acids by intramolecular hydrosilylation of β,γ-unsaturated acyloxysilanes has been developed.Application of the methodology in the synthesis of (2S,3R)-3-hydroxy-N-BOC-proline methyl ester is described.
Candida antarctica lipase B-catalyzed reactions of β-hydroxy esters: Competition of acylation and hydrolysis
Forro, Eniko,Galla, Zsolt,Fueloep, Ferenc
, p. 92 - 97 (2013/11/19)
The ester function of ethyl cis-(±)-2-hydroxycyclopentane-1- carboxylate [(±)-1] and ethyl (±)-5-hydroxycyclopent-1- enecarboxylate [(±)-2] was demonstrated to undergo hydrolysis, as a side-reaction, during asymmetric (E > 200) O-acylation with Candida antarctica lipase B (CAL-B) as catalyst and vinyl acetate as acyl donor in t-BuOMe at 30 C. This competition of acylation and undesirable hydrolysis draws attention to CAL-B-catalyzed non-hydrolytic resolutions where the substrates contain any hydrolysable functions. Enantiomerically enriched cis-2-hydroxycyclopentane-1-carboxylic acid (ee = 90%) and 5-hydroxycyclopent-1- enecarboxylic acid (ee = 47%) were prepared through de novo CAL-B-catalyzed hydrolysis of (±)-1 and (±)-2 with added H2O in t-BuOMe at 30 C.
Enantioselective ketoester reductions in water: A comparison between microorganism-and ruthenium-catalyzed reactions
Zeror, Saoussen,Collin, Jacqueline,Fiaud, Jean-Claude,Zouioueche, Louisa Aribi
experimental part, p. 1211 - 1215 (2010/10/20)
In the search for green chemistry methods for the enantioselective reduction of ketoesters Saccharomyces cerevisiae-and ruthenium-catalyzed reactions in water have been investigated. The highest enantiomeric excesses for the reduction of α-and β-ketoesters have been obtained by S. cerevisiae. Chiral ruthenium catalysts are active for the reduction of all ketoesters with low to moderate enantioselectivities depending on the nature of the substrate and ligand. Interestingly, for several substrates both enantiomers of the hydroxyesters have been obtained according either to the catalytic method or to the structure of the ligand.
Enantioselective reduction of prochiral ketones employing sprouted Pisum sativa as biocatalyst
Yadav, Jhillu S.,Subba Reddy, Basi V.,Sreelakshmi, Chittamuru,Rao, Adari Bhaskar
experimental part, p. 1881 - 1885 (2010/01/16)
Sprouted green peas have been used for the first time as biocatalysts for enantioselective reduction of prochiral ketones. The reactions are highly enantioselective to furnish chiral alcohols in good yields. The sprouted peas as biocatalysts are a cheap and easy way for generating some interesting chiral alcohols. This process is efficient and convenient to produce chiral secondary alcohols in water. Georg Thieme Verlag Stuttgart.
Asymmetric Michael-aldol tandem cyclization of ω-oxo-α,β-unsaturated esters with 10-mercaptoisoborneol methyl ether
Nishimura, Katsumi,Tsubouchi, Hiroshi,Ono, Masashi,Hayama, Tomoharu,Nagaoka, Yasuo,Tomioka, Kiyoshi
, p. 2323 - 2326 (2007/10/03)
The asymmetric reaction of ω-oxo-α,β-unsaturated esters with lithium chiral thiolates afforded the Michael-aldol tandem cyclization products in high yield and good stereoselectivity. Reductive desulfurization gave the corresponding optically pure 2-hydrox
Stereo- and chemoselective transfer hydrogenation of carbonyl groups with RuCl2(PPh3)3 and BINAP-Ru as catalysts and et3NH+H2PO2-·1,5H 2O as a hydrogen donor
Khai, Bui The,Arcelli, Antonio
, p. 6599 - 6602 (2007/10/03)
Using Et3NH+H2PO2-.1.5 H2O as a hydrogen donor, the RuCl2(Ph3P)3, RuCl2(PPh3)3 / C and BINAP-Ru proved highly active catalysts for transfer hydrogenation of ketones under milder conditions than other hydrogen donors. 2-Methyl-, 2-chloro-, 2-(ethoxycarbonyl)cyclohexanones and -cyclopentanones were reduced to the less stable axial alcohols in excellent diastereoisomeric excess (de: 90-100%), and the carbonyl group of α,β-unsaturated ketones was selectively reduced, in contrast with other hydrogen donors the C=C bond was reduced. Copyright
New Class of Chiral Diphosphine Ligands for Highly Efficient Transition Metal-Catalyzed Stereoselective Reactions: The Bis(diphenylphosphino) Five-membered Biheteroaryls
Benincori, Tiziana,Brenna, Elisabetta,Sannicolo, Franco,Trimarco, Licia,Antognazza, Patrizia,et al.
, p. 6244 - 6251 (2007/10/03)
The synthesis and application of three examples of a new class of chiral (C2) atropisomeric diphosphines characterized by two interconnected five-membered heteroaromatic rings, with hindered rotation around the interanular bond, are described.Optically pure (+)- and (-)-2,2'-bis(diphenylphosphino)-4,4',6,6'-tetramethyl-3,3'-bibenzothiophene (tetraMe-bitianp) (1a) and the parent unsubstituted system (+)- and (-)-bitianp (1b) were synthesized.They were found to be optically stable at 100 deg C and were successfully employed as ligands in the Ru(II)-catalyzed hydrogenation of α- and β-oxo esters to the corresponding α- and β-hydroxy esters and in the hydrogenation of olefinic substrates.The optical and chemical yields were comparable with those reported for the same Ru(II)-binap-catalyzed reactions carried out under the same experimental conditions.The 2,2'-bis(diphenylphosphino)-3,3'-bibenzofuran (1c), the oxygenated analogue of bitianp, was found to be configurationally unstable at room temperature.Complete structural X-ray elucidation of the Pd complexes of 1a-c is reported.The advantages of these biheteroaromatic ligands over the classical biaryl systems are discussed.
65. Homogeneous and Heterogeneous Asymmetric Reactions. Part 5. Diastereoselective and Enantioselective Hydrogenation of Cyclic β-Keto Esters on Modified Raney-Nickel Catalysts
Wittmann, Gyula,Goendoes, Gyoergy,Bartok, Mihaly
, p. 635 - 639 (2007/10/02)
The hydrogenations of methyl 2-oxocyclopentanecarboxylate (1), ethyl 2-oxocyclohexanecarboxylate (3), and 2-methylcyclohexanone (5) on unmodified Raney-Ni catalyst lead predominantly to the formation of the cis-hydroxy diastereoisomers of 2, 4, and 6, respectively (Scheme 2).In the asymmetric hydrogenations on catalysts modified with chiral tartaric acid (R,R)-C4H6O6/Raney-Ni and (R,R)-C4H6O6/NaBr/Raney-Ni), the predominance of the cis-isomer increases significantly.The hydrogenations of β-keto esters 1 and 3 proceed with an enantioselectivity of 10-15percent on the modified catalysts, while the similar hydrogenation of 5 yields optically inactive 6.The (1S,2R)-enantiomers of the cis-isomers of 2 and 4 are formed in larger quantity, whereas the (1R,2R)-enantiomers of the corresponding trans-isomers predominate (Scheme 1).The enantioselective formation of trans-2 and trans-4 can be interpreted mainly in terms of the asymmetric hydrogenation of cyclic β-keto esters through the keto form, while that of the corresponding cis-hydroxy esters proceeds through the enol form.
