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1.
Synthesis of α- and β-(aminomethyl)vinylphosphonates was achieved from vinyl bromide via a cross-coupling reaction with triethyl phosphite and by cross-metathesis of allyl bromide and vinylphosphonate, respectively. The 1,3-dipolar cycloaddition of these vinylphosphonates with a dipole in the presence of trifluoroacetic acid afforded selectively the β-aminopyrrolidinephosphonates. Syntheses of cis- and trans-γ-aminopyrrolidinephosphonates are also described.  相似文献   

2.
《Tetrahedron: Asymmetry》1999,10(2):243-254
Seven novel chiral lipophilic pyridyl-containing β-amino alcohol ligands have been synthesized by coupling of 6-alkoxymethyl-2-chloromethylpyridine 3 with the corresponding chiral β-amino alcohols or l-cysteine. Their metal ion complexes have been investigated as catalysts for the enantioselective hydrolysis of N-protected α-amino acid esters in aqueous comicellar solution. The results indicate that the hydrophobic interactions between substrate and metallocatalyst, the rigidity of the ligand, the hydroxyl group of the ligand acting as a nucleophile for the transacylation process, and the micellar microenvironment are important factors for the activity and enantioselectivity. Large rate accelerations (up to three orders of magnitude) and moderate enantioselectivities (up to 7.81 (kR/kS)) employing 4a–Cu2+ have been observed.  相似文献   

3.
Synthesis of novel pyrroloisoquinoline and indolizinoindole derivatives with β-lactam unit has been achieved by sequential intermolecular 1,3-dipolar cycloaddition reaction and Pictet-Spengler cyclization. The azomethine ylide derived from β-lactam imine of α-amino ester in the presence of silver acetate reacted with nitrostyrenes to give pyrrolidinyl β-lactam, which underwent Pictet-Spengler cyclization in presence of trifluoroacetic acid to give pyrroloisoquinolines and indolizinoindoles.  相似文献   

4.
In the work discussed in this paper, novel β-amino acid derivatives were prepared by Michael addition between 3-substituted-2-propenic acid and hydrazine hydrate. The optimum reaction conditions were determined by analyzing the effects of the ratio of the starting materials, temperature, and reaction time. The conclusions were: reaction temperature 80 °C, reaction time 8 h, n (3-substituted-2-propenic acid)/n (hydrazine hydrate) = 1:15. Products were characterized by measurement of melting point, elemental analysis, and IR and 1H NMR spectroscopy.  相似文献   

5.
Two furan derivatives of cispentacin have been synthesized starting from a d-mannitol derived conjugated nitroolefin through intramolecular nitrile oxide cycloaddition (INOC) as a key step.  相似文献   

6.
Synthesis of chiral cyclic β-amino ketones has been first reported via Ru-catalyzed asymmetric hydrogenation. High enantioselectivities were achieved by using (S)-C3-TunePhos chiral ligand (up to 94% ee).  相似文献   

7.
The Ag-catalyzed 1,3-dipolar cycloaddition of (Ε)-β-borylacrylates with azomethine ylides is described. The resulting 3-borylpyrrolidine derivatives were obtained in high yields and complete endo selectivities using AgOAc/dppe as catalyst system and B(dam) as boryl group. Transformation of the B(dam) group into pinacol borane and oxidation afforded 3-hydroxyproline derivatives in high yields.  相似文献   

8.
Novel polycyclic spiropyrrolidine oxindoles that bear two vicinal quaternary centers and an exocyclic CC double bond have been synthesized by a three-component reaction involving α,γ-dialkylallenoate esters, isatin derivatives and amino acids, by way of an endo-selective 1,3-dipolar cycloaddition. These reactions proceed in high yields and diastereoselectivities. The structures and relative stereochemistry of products were confirmed by NMR, HRMS and X-ray crystallography.  相似文献   

9.
10.
Highly enantioselective 1, 3-dipolar cycloaddition of 2-arylidene-benzofuran- 3(2H)-ones with imino esters catalyzed by thiourea?quaternary ammonium salts has been developed. This reaction provides efficient construction of a range of chiral spiro[benzofuran-2,3′-pyrrolidine] in high yields (up to 99%) and with good enantioselectivities (up to 99% ee) under mild conditions.  相似文献   

11.
张翱  阚颖  姜标 《中国化学》2000,18(2):220-224
Asymmetric 1,3-dipolar cydoaddition of nitrite oxides to an acryloyl ester (1) derived from 1,2:5,6-di-O-isopropylidene glucose (6) was studied. Solvent and temperature effect was discussed. The single diastereoisomer was isolated with high diastereoselective excess.  相似文献   

12.
The 1,3-dipolar cycloaddition products of C,N-disubstituted nitrones and different in situ prepared mono-N-substituted nitrones to η6-(styrene) chromium tricarbonyl and η6-(ethyl cynnamate) chromium tricarbonyl were synthesized and characterized by HPLC, IR, 1H NMR spectroscopy, and mass spectrometry. The resulted isoxazolidines were produced with a full regioselectivity and high stereoselectivity reached 100% in most cases.  相似文献   

13.
L-α-Amino acids catalyze 1,3-dipolar cycloaddition of methyl α-benzylideneamino acids to electron-deficient olefins in different solvents at room temperature. L-α-Amino acids ensure stereoselective formation of the corresponding syn,syn-azomethine ylides. The subsequent reaction with an active dipolarophile is stereospecific; it occurs as endo-cycloaddition with low asymmetric induction (up to ee 12%.). 3,4-Substituted 5-arylprolines were obtained in preparative yields using L-pyroglutamic acid or L-proline as catalyst.  相似文献   

14.
Summary A simple method is described for synthesizing cyclic -amino ketones by intramolecular cyclization of azlactones under the action of aluminum chloride.  相似文献   

15.
An expedient method for the synthesis of ferrocene grafted β-C-glycosydic spiroheterocycles is reported through 1,3-dipolar cycloaddition reaction (1,3-DC reaction). The novel C-glycosyl dipolarophiles derived from d-glucose, d-mannose, and d-ribose underwent neat [3+2] cycloaddition reaction with the azomethine ylides generated from 1,2-diketones and secondary amino acids to give the corresponding β-C-glycosidic heterocycles in good yields. The electrochemical behavior of the cycloadducts is also described.  相似文献   

16.
《Tetrahedron letters》1988,29(46):5949-5952
A novel oxidative ring-opening reaction of isoxazolidines upon treatment with an electrophile and subsequently with a basegives β-amino ketones and β-amino acid esters highly efficiently.  相似文献   

17.
A convenient synthetic procedure for the preparation of seven-membered cyclic α,β-dipeptides is described. Following coupling of N-protected α-amino acids with N-substituted β-amino acid tert-butyl esters, that affords linear α,β-dipeptides, the protecting groups at the terminal functionalities were removed and the open-chain dipeptides were cyclized with phenylphosphonic dichloride, PhP(O)Cl2, to give the desired cyclic α,β-dipeptides in good yields. NMR studies, X-ray diffraction analysis, and DFT calculations provided evidence for the conformation adopted by these cyclic dipeptides in solution, in the solid-state, and in the gas phase.  相似文献   

18.
A facile regio and stereoselective synthesis of novel spiro[indolin-3,2′-pyrrolidin]-2-one’s have been accomplished through 1,3-dipolar cycloaddition of azomethine ylides generated in situ from the reaction of isatin and benzyl amine with quinoline bearing dipolarophiles in good yields. The synthesized compounds were well characterized through different spectroscopic techniques, such as single crystal XRD, FTIR, NMR, and mass spectral analysis.  相似文献   

19.
Russian Journal of Organic Chemistry -  相似文献   

20.
Rhodococcus equi A4, Rhodococcus erythropolis NCIMB 11540 and Rhodococcus sp. R312 were investigated towards their ability to produce β-amino amides and acids from β-amino nitriles. The microorganisms show comparable trends: five-membered alicyclic 2-amino nitriles were transformed significantly faster than the six-membered compounds and the products of trans-2-amino nitriles (amides and acids) were formed considerably faster than the cis-counterparts (amides). The trans-five membered nitriles gave the amides (1b, 5b) in excellent enantiomeric excess (94-99%), the biotransformation of trans-six membered substrates resulted in the formation of the acid (3c, 7c) in excellent ee (87-99%). The ee's of the cis-compounds were throughout lower. Fifteen new substances were synthesized and characterized in the course of this work.  相似文献   

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