66997-64-6

Upstream product

• 108-05-4 vinyl acetate 
• 7367-87-5 3-hydroxyoctanoic acid methyl ester 
• 62344-14-3 (E)-methyl 3-oxo-6-octenoate 
• 22348-95-4 methyl 3-oxooctanoate 
• 163797-43-1 Methyl (E)-3-oxooct-5-enoate 
• 101392-66-9 (R)-4-(1,1-Dichloro-pentyl)-oxetan-2-one 
• 66-25-1 hexanal 
• 67-56-1 methanol 
• 2548-87-0 2-octen-1-al 
• 186581-53-3 diazomethane 
• 57024-78-9 2,2-dichlorohexanal 
• 33796-86-0 (S)-3-hydroxyoctanoic acid 
• 101392-69-2 (R)-4,4-Dichloro-3-hydroxy-octanoic acid methyl ester 

Relevant academic research and scientific papers

General enantioselective synthesis of butyrolactone natural products via ruthenium-SYNPHOS-catalyzed hydrogenation reactions

Enantioselective syntheses of several paraconic acids have been achieved using catalyzed asymmetric hydrogenation of β-keto esters with SYNPHOS as a ligand. This strategy allowed the short synthesis of biologically active (-)-methylenolactocin 1, (-)-protolichesterinic acid 2, (-)-phaseolinic acid 3 and (+)-roccellaric acid 4.

Factors affecting the lipase catalyzed transesterification reactions of 3-hydroxy esters in organic solvents

Chiral resolutions of racemic 3-hydroxy esters were performed in organic phases with lipases from Pseudomonas cepacia, Chromobacterium viscosum, and Porcine pancreas.The reaction conditions have been optimized with 3-hydroxy octanoic acid methyl ester.Different organic solvents have been tested showing a tendentious correlation with the hydrophobicity of the solvents expressed as log P.The reaction time was shortened six fold by using irreversible acylating agents.We have found solvent type, lipase type and acylating agent acting as tools for changing the enantioselectivity.Lipase from Pseudomonas cepacia was lyophilized at different pH and the influence of the amount of water added was investigated, resulting in the highest activity at the pH optimum and a denaturation of the lipase above 1 percent water (w/w lipase).The water activity was measured on-line with a humidity sensor.Water activities greater than 0.4 led to a decrease in enantioselectivity and reaction rate.In the optimized system the resolutions of other 3-hydroxy esters were tested.Aliphatic compounds reacted with lower enantioselectivity, only the substrates could be isolated in high enantiomeric purity.In contrast, aromatic 3-hydroxy esters were acylated by lipases with high stereoselectivity.A model of the active site of lipase from Pseudomonas sp. explained these experimental observations.

N-heterocyclic carbene-catalyzed radical reactions for highly enantioselective β-hydroxylation of enals

An N-heterocyclic carbene-catalyzed β-hydroxylation of enals is developed. The reaction goes through a pathway involving multiple radical intermediates, as supported by experimental observations. This oxidative single-electron-transfer reaction allows for highly enantioselective access to β-hydroxyl esters that are widely found in natural products and bioactive molecules.

Asymmetric synthesis of tetrahydrolipstatin and valilactone

The highly diastereoselective aldol reaction between acyl complexes of the iron chiral auxiliary [(η5-C5H5)Fe(CO)(PPh3)] and β-hydroxy aldehydes (obtained via a Noyori asymmetric hydrogenation), followed by a tandem oxidative decomplexation-cyclisation process gives access to β-substituted and α,β-disubstituted β-lactones in high ee. This methodology has been employed in the asymmetric syntheses of tetrahydrolipstatin and valilactone.

An improved asymmetric Reformatsky reaction mediated by (-)-N,N-dimethylaminoisoborneol

(-)-N,N-Dimethylaminoisoborneol ((-)-DAIB) was found to be an excellent ligand for the enantioselective addition of Reformatsky reagents to aromatic and aliphatic aldehydes. Enantioselectivities up to 93% ee were obtained with sulfur-containing aldehydes.

Optically active compound and process for producing the same

An optically active (2S,3R)-2-(3'-hydroxyacyl)aminoalkane-1,3-diol and a process for producing the same are disclosed. The compound is represented by the following general formula (1): STR1 wherein R1 represents a linear or branched, saturated aliphatic hydrocarbon group having 9 to 19 carbon atoms; R2 represents a linear or branched, saturated aliphatic hydrocarbon group having 1 to 19 carbon atoms; and symbol * means that the carbon atom is an asymmetric carbon atom of the S or R configuration. The optically active compound is a ceramide in which the fatty acid moiety has an optically active hydroxyl group in the 3-position.

Enantioselective ruthenium-mediated hydrogenation: Developments and applications

A general preparation of chiral ruthenium(II) catalysts and the homogeneous enantioselective hydrogenation of prochiral olefins and keto groups are presented. Some applications to the synthesis of biologically active compounds are reported.

Optically active ceramides and process for producing the same

An optically active (2S,3R)-2-(3'-hydroxyacyl)aminoalkane-1,3-diol and a process for producing the same are disclosed. The compound is represented by the following general formula (1): wherein R1represents a linear or branched, saturated aliphatic hydrocarbon group having 9 to 19 carbon atoms; R2represents a linear or branched, saturated aliphatic hydrocarbon group having 1 to 19 carbon atoms; and symbol * means that the carbon atom is an asymmetric carbon atom of the S or R configuration. The optically active compound is a ceramide in which the fatty acid moiety has an optically active hydroxyl group in the 3-position.

Practical asymmetric hydrogenation of β-keto esters at atmospheric pressure using chiral Ru (II) catalysts

New practical conditions of asymmetric hydrogenation of β-keto esters with chiral Ru(II) catalysts are described. It is now possible to carry out the reaction at atmospheric pressure. Under these conditions, β-keto esters are hydrogenated to β-hydroxy esters with excellent enantiomeric excesses (up to 99%) using chiral ruthenium (II) catalysts easily prepared in situ by treatment of commercially available (COD)Ru(2-methylallyl)2 in the presence of the appropriate chiral ligands such as Binap, MeO-Biphep and Me-Duphos.

ENANTIOSELECTIVE HYDROGENATION REACTIONS WITH A FULL SET OF PREFORMED AND PREPARED IN SITU CHIRAL DIPHOSPHINE-RUTHENIUM (II) CATALYSTS

The new class of 2-methylallyl ruthenium chiral diphosphines 1 are efficient in asymmetric hydrogenation of α,β unsaturated acids and allylic alcohols.The related chiral halogen-containing ruthenium catalysts 2 are prepared from 1 or in situ from (COD)Ru(η3-(CH2)2CHCH3)2 by ligand exchange with the chelating diphosphine followed by protonation (HX) in acetone.This procedure allows rapid screening of chiral phosphines, such as Diop, Chiraphos, Cbd, Bppm, Binap, β-glucophos, Biphemp, MeO-Biphep, Me-Duphos, in ruthenium mediated hydrogenations of prochiral substrates.A high efficiency is displayed by Ru-catalysts having atropisomeric ligands (e.e. up to 99percent), and a C2 symmetric bis(phospholane) has also emerged as a valuable ligand (Me-Duphos, e.e. up to 87percent not optimized).Asymmetric hydrogenation of β-keto esters can be conducted under quite mild conditions (4 atm. of H2, 50 deg C, e.e. up to 99percent), β-keto esters having a disubstituted double bond are also hydrogenated chemoselectively to unsaturated chiral alcohols under controlled conditions with excellent optical purities.