113034-32-5Relevant articles and documents
Practical Rh(I)-catalyzed asymmetric hydrogenation of β-(acylamino) acrylates using a new unsymmetrical hybrid ferrocenylphosphine-phosphoramidite ligand: Crucial influence of an N-H proton in the ligand
Hu, Xiang-Ping,Zheng, Zhuo
, p. 419 - 422 (2005)
(Chemical Equation Presented) Excellent enantioselectivities and high turnovers (S/C = 5000) were achieved in the Rh(I)-catalyzed asymmetric hydrogenation of both β-aryl-and β-alkyl-β-(acylamino)acrylates with a new unsymmetrical hybrid ferrocenylphosphine-phosphoramidite ligand, and the presence of an N-H proton in the ligand was demonstrated to have a crucial role in the enantioselectivity.
Nickel-catalyzed asymmetric transfer hydrogenation of olefins for the synthesis of α- And β-amino acids
Yang, Peng,Xu, Haiyan,Zhou, Jianrong
, p. 12210 - 12213 (2014)
The field of asymmetric (transfer) hydrogenation of prochiral olefins has been dominated by noble metal catalysts based on rhodium, ruthenium, and iridium. Herein we report that a simple nickel catalyst is highly active in the transfer hydrogenation using
The optically pure 3-amino-1-butanol method for the preparation of
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Paragraph 0060; 0061; 0072; 0073, (2016/12/22)
The invention provides a method for preparing optically pure 3-amino-1-butanol. The method comprises the following steps: reacting benzamide and acetoacetate under the catalytic action of p-toluenesulfonic acid to generate 3-benzamido-2-crotonate; carrying out catalytic hydrogenation reaction by using a chiral rhodium-diphosphine ligand compound as an asymmetric hydrogenation catalyst to generate 3(R)/(S)-benzamidobutyrate at high selectivity; reducing ester carbonyl group with hydroborate to generate 3(R)/(S)-benzamido-1-butanol; and finally, carrying out hydrolysis and benzoyl removal with concentrated hydrochloric acid to obtain the optically pure 3(R)/(S)-amino-1-butanol. The method has the advantages of cheap and accessible raw materials, simple technical operation, no need of resolution, high yield, low cost, environment friendliness and high optical purity of the product, and is more suitable for industrial production.
A 3 (R) / (S)-amino-1-butanol method for the preparation of
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Paragraph 0075-0078, (2017/01/17)
The invention provides a method for preparing 3(R)/(S)-amidogen-1-butanol. The method comprises the steps that firstly, benzamide reacts with acetoacetic ester under the catalyzing action of p-toluenesulfonic acid, so that 3-benzamido-2-butene acid ester is generated; secondly, catalytic hydrogenation is conducted by using a chiral rhodium-diphosphine ligand compound as a catalyst for enantioselective hydrogenation, so that 3(R)/(S)-benzamide butyrate is generated highly selectively; thirdly, benzoyl is removed by means of mixed solvent of concentrated hydrochloric acid and alcohol, so that 3(R)/(S)-amino-crotonic acid ester hydrochloride is generated; finally, optically pure 3(R)/(S)-amidogen-1-butanol is obtained after ester carbonyl is reduced by means of hydronoron. According to the method, the raw materials are low in cost and easy to obtain, the technological operation is easy and convenient, resolution is not needed, the yield is high, cost is low, environmental friendliness is achieved, the optical purity of product is high, and the method is more suitable for industrial production.
Synthesis of a new chiral bisphospholane ligand for the Rh(I)-catalyzed enantioselective hydrogenation of isomeric β-acylamido acrylates
Holz, Jens,Monsees, Axel,Jiao, Haijun,You, Jinsong,Komarov, Igor V.,Fischer, Christine,Drauz, Karlheinz,Boerner, Armin
, p. 1701 - 1707 (2007/10/03)
The highly stereoselective synthesis of a chiral silylphospholane has been described, which can be advantageously used as a building block under base-free conditions for the construction of diphosphines related to DuPHOS. The utility of silylphospholane is shown in the synthesis of a new bisphospholane ligand 1 (MalPHOS), which is characterized by a maleic anhydride backbone. The ligand forms with Rh(I) a complex with a larger bite angle P-Rh-P than the analogue Me-DuPHOS complex. Both complexes have been tested in the asymmetric hydrogenation of unsaturated α- and β-amino acid precursors of pharmaceutical relevance. In several cases, the new catalyst was superior in comparison to the Me-DuPHOS complex, in particular when (Z)-configured β-acylamido acrylates were used as substrates.
Preparation and asymmetric hydrogenation of β-aryl-substituted β-acylaminoacrylates
You, Jingsong,Drexler, Hans-Joachim,Zhang, Songlin,Fischer, Christine,Heller, Detlef
, p. 913 - 916 (2007/10/03)
The Rh-catalyzed asymmetric hydrogenation of β-aryl-substituted (E)-β-acylaminoacrylates, which were isolated for the first time, with, for example [Rh{(R,R)- (Et-FerroTANE)}(nbd)]+ as catalyst (see picture) proceeds under very mild conditions
Stereospecific synthesis of oligonucleotides containing crotonaldehyde adducts of deoxyguanosine
Nechev,Kozekov,Harris,Harris
, p. 1506 - 1512 (2007/10/03)
Crotonaldehyde reacts with DNA to form two diastereomeric 1,N2 cyclic adducts of deoxyguanosine. A synthesis of the two diastereomeric deoxynucleosides has been achieved by reaction of mixed diastereomers of 4-amino-1,2-pentanediol with 2-fluoro-O6-(trimethylsilylethyl)-deoxyinosine. The resulting N2-(1-methyl-3,4-dihydroxybutyl)-deoxyguanosine was treated with NaIO4, cleaving the vicinal diol to the aldehyde. Spontaneous cyclization gave the two diastereomers of the crotonaldehyde-adducted nucleoside that were readily separated by HPLC. The absolute configurations were assigned by an enantiospecific synthesis of one diastereomer from (S)-3-aminobutanoic acid. The synthetic strategy has been extended to preparation of a site-specifically adducted oligonucleotide by reaction of the mixed diastereomers of 4-amino-1,2-pentanediol with an 8-mer oligonucleotide containing 2-fluoro-O6-(trimethylsilylethyl)-deoxyinosine. The diastereomeric oligonucleotides were separated by HPLC and absolute configurations of the adducts were established by enzymatic digestion to the adducted nucleosides.
A convenient new route to piperidines, pyrrolizidines, indolizidines, and quinolizidines by cyclization of acetylenic sulfones with β- and γ-chloroamines. Enantioselective total synthesis of indolizidines (-)-167B, (-)-209D, (-)-209B, and (-)-207A
Back, Thomas G.,Nakajima, Katsumasa
, p. 4543 - 4552 (2007/10/03)
The methyl esters of (L)-phenylalanine and (L)-methionine underwent conjugate additions via their free amino groups to 1-(p-toluenesulfonyl)hexyne, followed by intramolecular acylation of the corresponding enamide anions and tautomerization to afford 2-benzyl-5-n-butyl-3-hydroxy-4-(p-toluenesulfonyl)pyrrole and 5-n-butyl-3-hydroxy-2-(2-methylthioethyl)-4-(p-toluenesulfonyl)pyrrole, respectively. The conjugate additions of a series of acyclic and cyclic secondary β- and γ-chloroamines to acetylenic sulfones proceeded similarly under mild conditions. The resulting adducts were deprotonated with LDA in THF at -78 °C, and the resulting sulfone-stabilized carbanions underwent intramolecular alkylation to afford cyclic enamine sulfones. Thus, acyclic γ-chloroalkylbenzylamines afforded the corresponding 2- or 2,6-disubstituted piperidines, while 2-(chloromethyl)-pyrrolidines, 2-(2-chloroethyl)pyrrolidines, 2-(chloromethyl)piperidines, and 2-(2-chloroethyl)-piperidines produced the corresponding 3-substituted pyrrolizidines, 5- or 3-substituted indolizidines, and 4-substituted quinolizidines, respectively. 8-Methyl-5-substituted indolizidines were also prepared from the appropriate methyl-substituted chloroamine precursor. Enantioselective syntheses were achieved by employing chiral chloroamines derived from amino acids or other enantiopure precursors. Further transformations of several of the products provided concise syntheses of four dendrobatid alkaloids. Thus, reduction of (8aS)-5-n-propyl-6-(p-toluenesulfonyl)-Δ-indolizidine with sodium cyanoborohydride in trifluoroacetic acid, followed by reductive desulfonylation, afforded (-)-indolizidine 167B. The corresponding 5-n-hexyl derivative similarly produced (-)-indolizidine 209D, while (-)-(8R,8aS)-8-methyl-5-n-pentyl-6-(p-toluenesulfonyl)-Δ5,6-indolizidine furnished (-)-indolizidine 209B. Finally, the similar reduction and debenzylation of (-)-(8R,8aS)-5-(2-benzyloxyethyl)-8-methyl-6-(p-toluenesulfonyl)-Δ-indolizid ine produced the corresponding 5-hydroxyethyl indolizidine. This was subjected to chlorination of the alcohol group with thionyl chloride and substitution with a higher order allyl cuprate reagent to afford (-)-indolizidine 207A.
A new diastereoselective synthesis of anti-α-alkyl α-hydroxy β-amino acids
Cardillo, Giuliana,Tolomelli, Alessandra,Tomasini, Claudia
, p. 155 - 161 (2007/10/03)
As part of an ongoing project concerning the synthesis of enantiomerically pure α-hydroxy β-amino acids, we have now developed a general strategy allowing the synthesis of anti-α-alkyl α-hydroxy β-amino acids. Our procedure involves the intermediate formation of trans-oxazolines, which are alkylated at C-5 with good to high diastereoselectivity and then hydrolysed under mildly acidic conditions, affording in quantitative yield the corresponding hydroxy amides. The starting (R)-3-amino-3-phenylpropanoic acid and (S)-3-aminobutanoic acid were obtained in enantiomerically pure form by selective enzymatic hydrolysis of the corresponding phenylacetylamides with penicillin G acylase.
Lewis Acid-Promoted 1,4-Addition to Chiral Imide Derivatives in the Synthesis of β-Amino Acids
Amoroso, Rosa,Cardillo, Giuliana,Sabatino, Piera,Tomasini, Claudia,Trere, Alessandra
, p. 5615 - 5619 (2007/10/02)
The 1,4-addition of O-benzylhydroxylamine to imides 3 in the presence of various Lewis acids is described.The reaction is performed in CH2Cl2 at -78 deg C and affords derivatives 4 and 5 in good chemical yields and in different diastereomeric ratios, depending on the Lewis acid employed.TiCl4 and Me2AlCl give opposite diastereoselectivities.Furthemore, enantiomerically pure β-amino acid 9 is obtained in good yield from compound 4a.
