12 results about "Asymmetric hydrogenation" patented technology

This invention discloses a chemical preparation method for pharmaceutical-grade dexborneol. The method employs Noyori asymmetric hydrogenation, asymmetric reduction of camphor, and the use of ruthenium as a catalyst. Under the action of phosphine ligands, dexborneol and a small amount of its isomer, isoborneol, are prepared. Then, under the action of trimethylchlorosilane, dexborneol, due to its spatial configuration, can form a silicon-oxygen bond with TMS, while isoborneol cannot. Isoborneol is removed by recrystallization to obtain a silyl ether protected compound of dexborneol. Dexborneol is then prepared under hydrochloric acid conditions and purified by recrystallization to obtain highly purified dexborneol. This route features mild reaction conditions, does not use highly toxic materials, and has a high yield, meeting the requirements for pharmaceutical-grade dexborneol.

The invention discloses a method for preparing a chiral benzhydrol compound through asymmetric hydrogenation of o-amido benzophenone under catalysis of rhodium. The chiral rhodium catalyst is generated in situ from a metal rhodium salt and a chiral phosphine-phosphoramidite ligand in various solvents. Compared with other methods for synthesizing chiral benzhydrol, the method has the characteristics of cheap catalyst, easiness in preparation of chiral ligand, mild reaction conditions, simplicity and convenience in operation, high yield, high enantioselectivity and the like, and can be applied to large-scale preparation of chiral benzhydrol compounds. The method is also suitable for efficient preparation of the rice plant growth regulation inhibitor (S)-Inabenide, the yield can reach 92%, the enantioselectivity can reach 96%, and the method has good industrial application prospects.

This invention relates to the field of pharmaceutical intermediates, and in particular to a method for synthesizing chiral indane. The method uses indane as a raw material, synthesizes an oxime, then an enamine, and subsequently synthesizes the trans-chiral indane via an asymmetric hydrogenation reaction using a ruthenium chiral bisphosphine catalyst, achieving high yield and high stereoselectivity. The advantages of this invention are: in the asymmetric hydrogenation reaction of the enamine, the trans-chiral indane is obtained with a content greater than 97%, an ee of 95%, and a yield greater than 90%; the catalyst is readily available; the operation is simple; the raw materials are readily available; there is minimal pollution from waste; and energy consumption is low, making it suitable for industrial production.

The present invention relates to the field of pesticide chemistry technology, and in particular, to a method for selectively and asymmetrically hydrogenating 4-substituted-1,2-dihydroquinoline and use thereof. The present invention discloses a selective, asymmetric hydrogenation reaction conducted on 4-substituted-1,2-dihydroquinoline in the presence of a chiral ligand and a rhodium catalyst. The selective, asymmetric hydrogenation method features ease to operate, a higher conversion rate, and higher enantioselectivity.

This invention provides a method for preparing chiral N-tert-butylsulfonamide compounds. The method uses N-tert-butylsulfonylimide as a starting material, employs Mn(CO)₅Br and a chiral PNN ligand as catalysts, and an alcohol as a solvent. A hydrogenation reaction occurs in this homogeneous catalytic system, yielding axially chiral diaryl nitrophenol compounds in high yield (99%) and with high ee values ​​(>99%). This reaction has the advantages of high efficiency, mild conditions, and environmental friendliness. The obtained chiral N-tert-butylsulfonamide can be deprotected with a sulfonyl protecting group to obtain the corresponding chiral primary amine.

Disclosed in the present invention is an asymmetric catalytic hydrogenation method for a cyclohexene derivative, comprising the following steps: under a hydrogen atmosphere, the cyclohexene derivative undergoes an asymmetric hydrogenation reduction reaction in the presence of a catalyst, an acid and a solvent. The asymmetric catalytic hydrogenation method provided by the present invention achieves high conversion and excellent selectivity for a cyclohexene derivative substrate, and the resulting reduction product has a high ee value of up to 99%, and is suitable for industrial scale-up production. The method can effectively improve the production efficiency and product purity, thereby meeting the requirements of large-scale production.

The invention discloses a method for preparing a chiral amine compound through asymmetric hydrogenation of ruthenium catalyzed imine. The chiral ruthenium catalyst is a chiral metal ruthenium complex prepared by reacting metal ruthenium salt with a chiral phosphine-phosphoramidite ester ligand and chiral diamine in a solvent and carrying out column chromatography. Compared with other chiral amine synthesis methods, the method provided by the invention has the characteristics of cheap catalyst, easy preparation of chiral ligand, mild reaction conditions, simple operation, high yield and enantioselectivity and the like, and can be applied to large-scale preparation of chiral amine compounds. The method is also suitable for synthesis of the key intermediate of the herbicide (S)-metolachlor, the yield can reach 92%, the enantioselectivity can reach 90%, and the method has good industrial application prospects.

This invention discloses a method for preparing optically active citronellol, comprising the following steps: preparing optically active R-citronellol by asymmetric hydrogenation of neraldehyde and / or geranialdehyde in the presence of a catalyst, wherein the catalyst comprises a transition metal rhodium and a bisphosphine ligand, wherein the mass of isopentenol in the raw material neraldehyde or geranialdehyde is 100-500 ppm of the mass of neraldehyde or geranialdehyde, and the mass of 3,7-dimethyl-2,6-octadienoic acid is 500-1000 ppm of the mass of neraldehyde or geranialdehyde; the preparation method of this invention can significantly improve the catalytic stability of optically active transition metal catalysts used for homogeneous catalysis and asymmetric hydrogenation, yielding R-citronellol with high optical purity, while simplifying the process flow, avoiding the introduction of new impurities, and exhibiting significant economic benefits.

The application belongs to the technical field of organic synthesis, and particularly relates to an amino nitrile compound with a remote chiral center and a preparation method and application thereof. The nickel-hydrogen catalytic asymmetric hydrogenation reaction provided by the application is realized through non-covalent pi-pi interaction between a cyano group in an olefin substrate and a chiral bisoxazoline ligand. The method not only realizes efficient and high-selectivity conversion of various olefin substrates and amine electrophilic reagents, but also is compatible with secondary alkyl amine electrophilic reagents, amide electrophilic reagents and benzisoxazole electrophilic reagents, thereby providing a reliable way for synthesizing chiral amino nitrile compounds (formula I) with a remote (beta-, gamma- and delta-) stereogenic center and various structures.

The application relates to the field of drug synthesis and discloses a one-pot enzyme method for preparing L-5-MTHF. The method provided by the application adds dihydrofolate reductase and tetrahydrofolate methyltransferase into folic acid, so that the folic acid is subjected to asymmetric hydrogenation reaction under the catalysis of dihydrofolate reductase (DHFR), an intermediate compound L-tetrahydrofolic acid is obtained, and then the L-tetrahydrofolic acid is subjected to catalysis by tetrahydrofolate methyltransferase (DmdA) to obtain L-5-MTHF with optical purity. The one-pot enzyme method can avoid the separation step of an intermediate product, meanwhile, the produced intermediate is converted into the product L-5-MTHF at the moment, the product is used immediately, and the problem of product inhibition is avoided. The method for preparing L-5-MTHF has high yield, great application value and market prospect.

The application relates to the technical field of asymmetric catalysis, and particularly discloses a tetradentate ligand, a catalyst and application of the tetradentate ligand and the catalyst in synthesis of chiral 2-substituted tetrahydroquinoline derivatives. The tetradentate ligand of formula II-a or II-b is reacted with a metal precursor to obtain a catalyst which can be used in asymmetric hydrogenation. The catalyst can be used in synthesis of chiral 2-substituted tetrahydroquinoline derivatives. The process for preparing chiral 2-substituted tetrahydroquinoline derivatives by using the catalyst does not need additional strong acid additives, is friendly to equipment, is simple to operate, has the advantages of high yield, high enantioselectivity of products, low cost and the like.

This invention relates to the field of asymmetric hydrogenation technology, specifically disclosing an electron-rich chiral bisphosphine ligand, specifically L1 to L5, and disclosing the synthetic pathways of ligands L1 to L5 and the intermediate compounds 1 to 5 in the synthetic route. This invention uses L1 to L7 to complex with different transition metal precursors, such as [Rh(COD)2]BAr. F 4. A series of stable, simple-to-prepare, and low-cost catalysts were obtained, including [Rh(NBD)2]BF4, [Rh(NBD)Cl]2, Rh(acac)(CO)2, Rh(ethylene)2(acac), and [Rh(ethylene)2Cl]2. These catalysts can be used for asymmetric hydrogenation, especially in the asymmetric hydrogenation step of the N-Boc amino alcohol synthesis pathway, effectively overcoming the steric hindrance effect under different amino protecting group conditions. With the participation of this catalyst, the asymmetric hydrogenation step in the N-Boc amino alcohol synthesis pathway overcomes the technical defects of using hazardous materials in existing technologies, improving the production safety factor. Furthermore, with the participation of this catalyst, the asymmetric yield and selectivity both meet the requirements of industrial production.