89537-70-2Relevant academic research and scientific papers
Rhodium complex with unsymmetrical vicinal diamine ligand: excellent catalyst for asymmetric transfer hydrogenation of ketones
Deshpande, Sudhindra H.,Shende, Vaishali S.,Shingote, Savita K.,Chakravarty, Debamitra,Puranik, Vedavati G.,Chaudhari, Raghunath V.,Kelkar, Ashutosh A.
, p. 51722 - 51729 (2015/06/25)
New unsymmetrical vicinal diamine ligands with systematic variation in the regio and stereo positions in the amine and sulphonamide groups were synthesized from cheap starting material such as norephedrine. Catalytic Asymmetric Transfer Hydrogenation (ATH) of aromatic alkyl ketones has been investigated using transition metal complexes and new derivatives of monotosylated unsymmetrical vicinal diamine ligands using sodium formate as the hydrogen source, in water and methanol. Chiral secondary alcohols were obtained with excellent enantioselectivity (>95% ee) and conversion of ketones (>95%) with [Rh(Cp)Cl2]2 and ligand 4 as a catalyst. Enantioselectivity was found to be slightly higher with the use of methanol as a solvent for ATH of ketones with sodium formate as the hydrogen source compared to water as a solvent and was found to be consistent with all the ketones investigated. The reaction mixture is homogeneous in methanol unlike in water, where substrate and product are insoluble in water and form separate phase, sodium formate being soluble in water. The activity and enantioselectivity obtained for ATH of ketones using [Rh(Cp)Cl2]2 and unsymmetrical vicinal diamine ligand as catalyst was comparable with the C2 symmetric benchmark ligands like TsDPEN ((1R,2R)-N-(p-tolylsulfonyl)-1,2-diphenylethylene-diamine), and TsCYDN ((1R,2R)-N-(p-tolylsulfonyl)-1,2-cyclohexyl,diamine) under similar reaction conditions. To the best of our knowledge, this is first example of the ATH of ketones with good activity and high enantioselectivity with [Rh(Cp)Cl2]2 and unsymmetrical vicinal diamine ligands as catalyst systems.
A robust Ru-PNNP catalyst system for the asymmetric hydrogenation of α,β-unsaturated ketones to allylic alcohol
Lu, Sheng-Mei,Gao, Qiang,Li, Jun,Liu, Yan,Li, Can
supporting information, p. 7013 - 7016 (2013/12/04)
A robust and stable Ru-Biphosphinobioxazoline catalyst system is discovered for the highly enantioselective hydrogenation of enones to allylic alcohols. A series of acyclic α,β-unsaturated ketones react well affording the desired products in high yields (
An umpolung sulfoxide reagent for use as a functionalized benzyl carbanion equivalent
Pinna, Giovanni,Bellucci, Maria Cristina,Malpezzi, Luciana,Pisani, Laura,Superchi, Stefano,Volonterio, Alessandro,Zanda, Matteo
, p. 5268 - 5281 (2011/08/06)
N-Methyl ortho-carbamoylaryl benzyl sulfoxides can be used as synthetic equivalents for α-hydroxy, α-chloro, and α-acetammido benzyl carbanions by means of a two-step sequence involving highly diastereoselective α-C-alkylation with alkyl halides followed by displacement of the sulfinyl residue (which can be recovered and recycled) by a hydroxyl, a chlorine or an acetamido, respectively, under non-oxidative Pummerer conditions. The scope and limits of the method, including a stereoselective version of the reaction, as well as the mechanism of the process are discussed in detail.
Ir- and Ru-catalyzed sequential reactions: Asymmetric α-alkylative reduction of ketones with alcohols
Onodera, Gen,Nishibayashi, Yoshiaki,Uemura, Sakae
, p. 3819 - 3822 (2007/10/03)
(Chemical Equation Presented) The compatibility between [{IrCl(cod)} 2] and ruthenium complex 1 to achieve asymmetric α-alkylative reduction of prochiral ketones with primary alcohols is an essential factor in obtaining optically active alcohols with elongation of the carbon skeleton in good yields with a high enantioselectivity.
Stereoselective Transformations with Configurationally Labile α-Phenylselenoalkyllithium Compounds
Hoffmann, Reinhard W.,Klute, Wolfgang
, p. 694 - 700 (2007/10/03)
Complexation of the configurationally labile α-phenylselenoalkyllithium compound 8 with 1,2-bisdimethylaminocyclohexane 15 led to two diastereomeric complexes 13 and 14 in a 7:3 ratio.Owing to ligand acceleration the complexes 13 and 14 added more rapidly
Preparation of polyfunctional diorganomercurials and their transmetallation to diorganozincs. Applications to the preparation of optically active secondary alcohols
Rozema, Michael J.,Rajagopal, Duddu,Tucker, Charles E.,Knochel, Paul
, p. 11 - 27 (2007/10/02)
Two new methods of preparation of functionalized diorganomercurials have been developed.The first method involves a substitution reaction of (ICH2)2Hg with zinc-copper reagents FG-RCu(CN)ZnI in THF/DMF at -60 deg C.Functional groups such as an ester, nitrile, ketone, phosphonate, halide, and boronic ester are tolerated in this reaction.The second method involves a reductive transmetallation between polyfunctional organozinc halides and mercurous chloride (Hg2Cl2).This very convenient procedure provides a rapid route to various functionalized diorganomercurials in good yields (61-89percent yield).The synthetic utility of these mercury organometallics is demonstrated.Their transmetallation with zinc dust (toluene, 80 deg C, 3-5 h) affords dialkylzincs which add enantioselectively to aldehydes in the presence of a catalytic amount (20 molpercent) of the norephedrine derivative 13.This transmetallation can also be used to prepare stereoselectively (E)-alkenylzinc halides (> 98percent E).Addition of Cl(H)ZrCp2 to (E)-5-chloropentenylzinc bromide in CH2Cl2 (25 deg C, 1 min) affords a 1,1-bimetallic of zinc and zirconium Cl(CH2)4CH(ZnBr)ZrCp2(Cl) which reacts stereoselectively with an aldehyde providing the (E)-disubstituted olefin (49percent yield; 100percent E).
Enantioselective Preparation of sec. Alcohols from Aldehydes and Dialkyl Zinc Compounds, Generated in situ from Grignard Reagents, Using Substoichiometric Amounts of TADDOL-Titanates
Bussche-Huennefeld, Joanna Linda v.,Seebach, Dieter
, p. 5719 - 5730 (2007/10/02)
Using the Schlenk trick (precipitation of MgX2 from etheral solutions by the addition of 1,4-dioxane) mixtures of a Grignard reagent RMgX (X = Cl, Br, I) and 0.5 equiv.ZnCl2 in Et2O can be converted to zinc alkyls R2Zn which in turn are added with enantioselectivities of up to 99:1 to aliphatic and aromatic aldehydes in the presence of Ti(OCHMe2)4 and a chiral titanate derived from an α,α,α',α'-tetraaryl-1,3-dioxolane-4,5-dimethanol (TADDOL).Grignard reagents containing remote double bonds, benzene rings, or acetal groups can also be employed.Different TADDOLs are compared with respect to their usefulness in this kind of enantioselective reactions.
METHOD FOR DETERMINATION OF ENANTIOMERIC COMPOSITION AND ABSOLUTE CONFIGURATION OF 2,3-DEUTERATED 3-ALKYLPROPANOLS
Furukawa, Jun,Iwasaki, Shigeo,Okuda, Shigenobu
, p. 5257 - 5260 (2007/10/02)
Assignments were made for diastereotopic methylene protons on C-2 and C-3 of 1-phenyl-3-alkylpropanols in Eu(fod)3-enhanced 1H-NMR spectra to develope a generally applicable method to determine enantiomeric composition and absolute configuration of 2 and/or 3-deuterated 3-alkylpropanols.
