181185-40-0

Basic information

• Product Name: 2-Hexanone, 4-hydroxy-5-methyl-, (4R)- (9CI)
• Synonyms: 2-Hexanone, 4-hydroxy-5-methyl-, (4R)- (9CI)
• CAS NO: 181185-40-0
• Molecular Formula: C₇H₁₄O₂
• Molecular Weight: 130.18486
• Product Categories: ACETYLGROUP
• Mol File: 181185-40-0.mol

Chemical Properties

• Appearance: /
• CAS DataBase Reference: 2-Hexanone, 4-hydroxy-5-methyl-, (4R)- (9CI)(CAS DataBase Reference)
• NIST Chemistry Reference: 2-Hexanone, 4-hydroxy-5-methyl-, (4R)- (9CI)(181185-40-0)
• EPA Substance Registry System: 2-Hexanone, 4-hydroxy-5-methyl-, (4R)- (9CI)(181185-40-0)

Safety Data

• Hazardous Substances Data: 181185-40-0(Hazardous Substances Data)

Upstream product

• 78-84-2 isobutyraldehyde 
• 67-64-1 acetone 
• 123-42-2 4-Hydroxy-4-methyl-2-pentanone 
• 97169-20-5 N,N-Dimethyl-N'-[1-methyl-2-((R)-toluene-4-sulfinyl)-eth-(E)-ylidene]-hydrazine 

Relevant articles and documents

Asymmetric aldol reactions catalyzed by new spiro diamine derivatives

Two new organocatalysts derived from l-proline and a novel chiral spiro diamine bearing a C2 symmetric backbone, were introduced for an asymmetric aldol reaction in moderate to good asymmetric induction in up to 76% ee and high yields.

Tuning the sense of product stereochemistry in aldol reactions of acetone and aromatic aldehydes in the presence of water with a single chiral catalyst

We report the aldol addition of acetone to aromatic aldehydes in the presence of a large amount of water where the stereochemical outcome of the reactions can be tuned with achiral salt additives using a single proline-derived catalyst. Depending on the nature of the added salt the (R) and (S) enriched products could be obtained. In the reaction of 2-nitrobenzaldehyde with acetone, NaOAc promoted the formation of the (S)-enantiomer (20% ee) while using NH4Cl the (R)-enantiomer was obtained in excess (58% ee). A similar inversion was observed for several other aromatic aldehydes.

An unexpected inversion of enantioselectivity in direct asymmetric aldol reactions on a unique L-proline/γ-Al2O3 catalyst

L-proline adsorbed on γ-Al2O3 unexpectedly switches the enantioselectivity of the direct asymmetric aldol reaction of acetone with p-nitrobenzaldehyde from 68% ee (R configuration for free L-proline catalyst) with 80% yield to 21% ee (S configuration) with 78% yield. The inversion of enantioselectivity was also observed in the direct asymmetric aldol reactions of acetone with several other aromatic aldehydes catalyzed by the L-proline adsorbed on γ-Al2O3. This inversion phenomenon is found to be general for different types of amino acids adsorbed on γ-Al2O3. The hydroxyl groups on γ-Al2O3 are found to be involved in the inversion induction of enantioselectivity in these direct asymmetric aldol reactions.

Asymmetric aldol reactions in poly(ethylene glycol) catalyzed by L-proline

A rapid L-proline catalyzed direct aldol reaction between various aldehydes and acetone was achieved using PEG as the solvent with comparable enantioselectivities and yields to those obtained in other solvents. Recycling the catalyst and solvent (PEG) was possible 10 times without loss of activity.

Proline-catalyzed asymmetric aldol reaction in guanidine-derived ionic liquids

A remarkable improvement of both the chemical yield (from 6% to 82%) and the enantiomeric excess (up to >99%), of (S)-proline catalyzed direct aldol reactions of a wide range of aldehydes with acetone was found when hexasubstituted or pentasubstituted guanidinium salts were added as ionic liquids. Effects of temperature, amount of proline and the type of guandidinium salts on the outcome of the reaction were investigated.

Combining prolinamides with 2-pyrrolidinone: Novel organocatalysts for the asymmetric aldol reaction

Peptides and especially prolinamides have been identified as excellent organocatalysts for the aldol reaction. The combination of prolinamides with derivatives bearing the 2-pyrrolidinone scaffold, deriving from pyroglutamic acid, led to the identification of novel organocatalysts for the intermolecular asymmetric aldol reaction. The new hybrids were tested both in organic and aqueous media. Among the compounds tested, 22 afforded the best results in petroleum ether, while 25 afforded the products in brine in high yields and selectivities. Then, various ketones and aldehydes were utilized and the products of the aldol reaction were obtained in high yields (up to 100%) with excellent diastereo- (up to 97:3 dr) and enantioselectivities (up to 99% ee).

Unusual enantioselectivities in heterogeneous organocatalyzed reactions: Reversal of direction using proline di- versus tri-peptides in the aldol addition

The heterogeneous asymmetric direct aldol reactions between aldehydes (2-nitrobenzaldehyde, 2-methylpropanal) and ketones (acetone, cyclohexanone) in the presence of polystyrene (PS) resin supported di- and tripeptides were studied under otherwise identic

Improved conditions for the proline-catalyzed aldol reaction of acetone with aliphatic aldehydes

The proline-catalyzed asymmetric aldol reaction between aliphatic aldehydes and acetone has, to date, remained underdeveloped. Challenges in controlling this reaction include avoiding undesired side reactions such as aldol condensation and self-aldolization. In recent years we have developed optimized conditions, which enable high yields and good to excellent enantioselectivities, and which are presented in this communication. Georg Thieme Verlag Stuttgart New York.

Reversal of enantioselectivity in aldol reaction: New data on proline/λ-alumina organic-inorganic hybrid catalysts

We report new results on the aldol reactions between aldehydes of three different types (aromatic, aliphatic and cycloaliphatic) and acetone/cycloalkanones as reaction partners, driven by organic-inorganic hybrid catalyst Pro/λ-Al2O3. In contrast to the homogeneous liquidphase reaction, over Pro/λ-Al2O 3reversal of the enantioselection in up to 20-40 % ee depending on the structure of the aldehyde was observed in reactions of acetone. Reversal of the ee in the presence of c-Al2O3cannot be generalized, as it has only been observed for acetone among the ketones studied by us. It was proven using methods of a great variety such as ultrasonic irradiation, reuse measurements on used catalyst and the filtrate of the first reaction, measurements on the L-Pro-L-Pro(OH) dipeptide, studies using mixtures of L-Pro and D-Pro that the organic-inorganic hybrid catalyst Pro/λ-Al 2O3formed in situ is responsible for reversal of the ee. In the reactions of cycloalkanones there is presumably competition between the liquid-phase and the surface reaction over Pro/ c-Al2O 3with preference for the former. Based on these results a surface reaction pathway was proposed. Although, the ees obtained under heterogeneous catalytic conditions are low, further studies may lead to application of this unusual phenomenon for obtaining chiral heterogeneous catalysts suitable for the preparation of the desired enantiomer of a chiral compound using the same chiral source. Springer Science+Business Media New York 2013.

Reversal of the enantioselectivity in aldol addition over immobilized di- and tripeptides: Studies under continuous flow conditions

Heterogeneous asymmetric direct aldol reactions between aldehydes (2-nitrobenzaldehyde, 2-methylpropanal) and acetone catalyzed by polystyrene resin (PS) supported di- and tripeptides H-Pro-Pro-, H-Pro-Pro-Pro-, H-Pro-Glu(OH)-, H-Pro-Pro-Glu(OH)-, H-Pro-Asp(OH)-, H-Pro-Pro-Asp(OH)-, H-Ser-Glu(OH)-, H-Ser-Ser-Glu(OH)-, H-Val-Glu(OH)-, H-Val-Val-Glu(OH)-MBHA-PS, were studied under identical experimental conditions at room temperature in a continuous-flow fixed-bed reactor (CFBR) system. In the asymmetric aldol reactions reversal of enantioselectivity was observed on H-Pro-Pro-Glu(OH)- and H-Pro-Pro-Asp(OH)-MBHA-PS-supported catalysts (ee 42-67% S) as compared to the H-Pro-Glu(OH)- and H-Pro-Asp(OH)-MBHA-PS-supported catalyst (ee 28-82% R). In the case of H-Pro-Pro- and H-Pro-Pro-Pro-MBHA-PS-supported catalysts reversed enantioselectivity was observed by using the benzoic acid additive (12% S) as compared to the H-Pro-MBHA-PS catalyst (25% R). The stability of the catalysts in the flow system was consistent with the heterogeneous character of the reaction, as was the linear behavior obtained using mixtures of l- and d-enantiomers of the supported H-Pro-MBHA-PS catalyst. The enamine character of the reaction intermediates was supported by ESI-MS measurements. Based on these and the computed structure of the peptides, the conformation of the intermediate adducts is held responsible for chiral induction, therefore for the enantioselectivity inversion observed in these reactions.