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Giuliana Cardillo Luca Gentilucci Elisa Mosconi Alessandra Tolomelli Stefano Troisi Eusebio Juaristi 《Tetrahedron》2010,66(27-28):4994-4999
A pratical, highly enantioselective method for the synthesis of dehydro-β-amino acids was developed starting from easily accessible enantiopure allylic carbonates. The substitution with amines for C–N bond formation on these substrates bearing substituents on the Cα, Cβ, and Cγ position of the allylic system has received, until now, little attention. The reactions, carried out under palladium-catalyzed conditions, resulted in good yields and complete regioselectivity. Moreover, starting from enantiopure carbonates, complete retention of the configuration could be observed, affording enantiopure allylic amines. 相似文献
3.
(S)-2-[(R)-Fluoro(phenyl)methyl]oxirane is a new, synthetic, yet enantiopure, chiral resolution reagent, readily obtained from enantiopure (2S,3S)-phenylglycidol, that reacts with a variety of alpha-chiral primary and secondary amines in a straightforward manner through a regioselective ring-opening. Diastereomeric products are easily identified and quantified by (19)F, (1)H, and (13)C NMR and by HPLC, which makes this fluorinated compound a most versatile reagent for the analysis of scalemic mixtures of amines. [reaction: see text] 相似文献
4.
Photolysis of enantiopure N-sulfinyl amines (sulfinamides) in Et2O-MeOH gives amines in good yield without racemization. 相似文献
5.
Catalytic and enantioselective synthesis of amino acids is a subject of intense interest in the field of asymmetric catalysis. Traditionally, researchers have concentrated their efforts largely on the design and discovery of enantiopure catalysts for the Strecker reaction, alkylation of tert-butyl gylcinate-benzophenone, electrophilic amination of carbonyl compounds, and hydrogenation of N-acyl-aminoacrylic acid; however, the scope of these reactions is limited. In this paper, we report on a different approach to amino acids based on an expeditious route to enantiopure allylic amines. A highly enantioselective and catalytic vinylation of aldehydes leads to allylic alcohols that are then transformed to the allylic amines via Overman's [3,3]-sigmatropic rearrangement of imidates. Oxidative cleavage of the allylic amines furnishes the amino acids in good yields and excellent ee's. The scope and utility of this method are demonstrated by the synthesis of challenging allylic amines and their subsequent transformation to valuable nonproteinogenic amino acids, including both D and L configured (1-adamantyl)glycine. 相似文献
6.
Ghosh A Sieser JE Caron S Couturier M Dupont-Gaudet K Girardin M 《The Journal of organic chemistry》2006,71(3):1258-1261
An efficient method for intermolecular N-arylation of oxazolidinones using catalytic copper in the presence of a bidentate ligand is reported. The conditions allow the use of copper and can be used to prepare enantiopure N-aryl beta-amino alcohols. A short, scalable synthesis of CJ-15,161 is also reported. The required amines were obtained from the precursor alpha-amino acids or, more conveniently, from the corresponding 1,2-amino alcohols. 相似文献
7.
Reginato G Pezzati B Ienco A Manca G Rossin A Mordini A 《The Journal of organic chemistry》2011,76(18):7415-7422
An efficient synthesis of various protected syn-β-sulfenyl amides is described. These are prepared from the corresponding enantiopure amino allylsilanes which are in turn obtained from naturally occurring amino acids. The key step for introduction of the sulfur substituent is a diastereoselective electrophilic sulfodesilylation which is carried out with phthalimidesulfenyl chloride. The resulting homochiral β-phthalimidesulfenyl amines with an allylic sulforated stereogenic center are useful building blocks, as they represent a starting point for subsequent functional manipulations. 相似文献
8.
Sortais JB Ritleng V Voelklin A Holuigue A Smail H Barloy L Sirlin C Verzijl GK Boogers JA de Vries AH de Vries JG Pfeffer M 《Organic letters》2005,7(7):1247-1250
[reaction: see text] Ruthenacycles obtained by cyclometalation of enantiopure aromatic primary or secondary amines with [(eta6-benzene)RuCl2]2 or with [(eta6-p-cymene)RuCl2]2 are efficient catalysts for asymmetric transfer hydrogenation (TOF up to 190 h(-1) at room temperature). Enantioselectivities in the transfer hydrogenation of acetophenone ranged from 38% to 89%. It is possible to prepare the catalysts in situ, which allows the use of high throughput experimentation. 相似文献
9.
Parvulescu AN Jacobs PA De Vos DE 《Chemistry (Weinheim an der Bergstrasse, Germany)》2007,13(7):2034-2043
Palladium catalysts on alkaline-earth supports were studied as new heterogeneous catalysts for racemization of chiral benzylic amines such as 1-phenylethylamine. Particularly 5 % Pd/BaSO(4) and 5 % Pd/CaCO(3) were able to selectively racemize amines, with minimal formation of secondary amines or hydrogenolysis to ethylbenzene. In contrast, these side reactions were pronounced on Pd/C. A reaction mechanism is proposed that is consistent with the reaction kinetics. The catalyst activity was found to depend on the number of available surface Pd atoms, determined by titration with CO. The selectivity crucially depends on the rate of condensation of the amine and the primary imine, which is highest on Pd/C. The racemization catalysts were combined in one pot with an immobilized lipase to perform dynamic kinetic resolution of chiral amines. High yields (up to 88 %) of essentially enantiopure amides were obtained in a single step. The chemo-enzymatic catalyst system proved to be stable and could be reused without losing the initial activity. 相似文献
10.
Laleu B Herse C Laursen BW Bernardinelli G Lacour J 《The Journal of organic chemistry》2003,68(16):6304-6308
Chiral acridinium cations, easily prepared by reaction of enantiopure primary amines and tris(2,6-dimethoxy)trityl cation, display restricted rotations around the C(sp(3))-N(sp(2)) bond. A bending of the aromatic backbone and "out-of-plane" displacements of C(9) and N(10) atoms are enforced if bulky amines are introduced. 相似文献
11.
[reaction: see text]. Two novel chiral hydrazine resins for asymmetric solid-phase synthesis have been developed. The enantiopure beta-methoxyamino auxiliaries, derived from trans-4-hydroxy-(S)-proline and (R)-leucine, were attached to Merrifield resin and transformed into their corresponding hydrazines. Immobilization of various aldehydes, followed by 1,2-addition of organolithium reagents to the resulting enantiopure hydrazones and reductive cleavage from the solid support, furnished alpha-branched amines, which were isolated as their corresponding amides in good overall yields and enantiomeric excesses of up to 86%. 相似文献
12.
《Tetrahedron: Asymmetry》1999,10(10):1831-1834
The palladium catalysed arylation of amines is employed to prepare selectively a range of new, mono-N-arylated, enantiopure diamine ligands. The ligands were tested in the catalytic asymmetric transfer hydrogenation of acetophenone. 相似文献
13.
A Valuable Synthetic Route to the Enantiopure Functionalized N-Substituted Aziridines 总被引:2,自引:0,他引:2
Chiral butyrolacto[3,4-b]-2(S)-6(R)-1-N-akylaziridines 7 were synthesized in enantiopure form utilizing racemic 5-methoxy-3-bromo-2(5H)-furanone (5) and available amines (6) as key precursors. After highly effective reduction of 7, the functionaiized 2(S),3(R)-dihyroxymethyl-N-alkylaziridines (8) were obtained in good yields with ≥98% ee. This is a simple and pratical method for the preparation of enantiopure aziridines which are important intermediates in the synthesis of biologic active molecules. 相似文献
14.
Boland NA Casey M Hynes SJ Matthews JW Smyth MP 《The Journal of organic chemistry》2002,67(11):3919-3922
A novel procedure for the preparation of enantiopure 1,4-disubstituted 2-imidazolines is reported. Enantiopure beta-amino alcohols are converted into N-hydroxyethylamides, which are reacted with excess thionyl chloride, or with thionyl chloride followed by phosphorus pentachloride to yield N-chloroethylimidoyl chlorides. These intermediates are treated with amines and anilines to produce N-chloroethylamidines, which are converted into imidazolines upon workup with aqueous hydroxide. The method is simple and efficient and has been used to prepare a wide variety of enantiopure imidazolines, in a modular fashion, from readily available amino alcohols. 相似文献
15.
SUN Xiao-Xia SUN Shang-Jin LIAO Jian WU Jia-Shou CUI Xin ZHU Jin DENG Jin-Gen 《有机化学》2003,23(Z1):60-60
Since its introduction in 1997, tert-butanesulfinamide (1) has proven to an extremely versatile chiral ammonia equivalent for the asymmetric synthesis of amines[1]. However, practical methods for the preparation of enantiopure 1 are very few.[2] 相似文献
16.
Short Synthesis of Enantiopure Thieno[2,3‐f]triazolo[1,5‐a][1,4]diazepines and Thieno[2,3‐f][1,4]diazepin‐5‐ones
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Giorgio Molteni 《Journal of heterocyclic chemistry》2014,51(Z1):E329-E331
Starting from 2‐carboxy‐3‐thenylazide 1 and enantiopure amines 2 as the chiral building blocks, we developed a two‐step synthesis of the title compounds involving an intramolecular azide cycloaddition as the key step. 相似文献
17.
A stereoselective decarboxylative aldol addition of β- and α-keto acids in the presence of catalytic amounts of amines is described. By the optional deployment of chiral enolizable aldehydes an access to enantiopure configurative defined ketopentoses, ketohexoses, or ketoheptoses is given. 相似文献
18.
The addition of enantiopure alpha-metalated vinyl and dienyl sulfoxides to enantiomerically pure N-sulfinimines takes place with high diastereoselectivity primarily directed by the N-sulfinimine sulfur. The resulting allylic amines have been further transformed into highly functionalized 3-sulfinyl and 3-sulfonyl 2,5- cis-dihydropyrroles by reaction with electrophiles. 相似文献
19.
Concellón JM Rivero IA Rodríguez-Solla H Concellón C España E García-Granda S Díaz MR 《The Journal of organic chemistry》2008,73(15):6048-6051
The transformation of enantiopure (2R,4R)- and (2S,4S)-N,N-dibenzyl-1,2:4,5-diepoxypentan-3-amine, 1 and 2, into the corresponding enantiopure (3S,5S)- and (3R,5R)-3,5-dihydroxy-3-aminopiperidines, 3 and 4 respectively, is described. The opening of the two epoxide rings with a range of amines takes place with total regioselectivity and high yields, in the presence of LiClO4. A mechanism to explain this transformation is proposed. 相似文献
20.
Treatment of acyclic α-hydroxy and α-tosylamino sulfinyl dienes with amines affords enantiopure 1,4-diol or 1,4-hydroxysulfonamide derivatives in good yields and diastereoselectivities. This one-pot procedure entails a conjugate addition that triggers a diastereoselective sulfoxide-sulfenate [2,3]-sigmatropic rearrangement. 相似文献