- Bis(o-nitrophenyl) carbonate as a new reagent for the synthesis of chiral oxazolidin-2-ones
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Bis(o-nitrophenyl) carbonate reacts under mild conditions with chirals 1,2-amino alcohols and, after addition of DMAP, affords the corresponding oxazolidin-2-ones in very good yields.
- Simon, Monika,Micle, Andreea,Badea, Valentin,Csunderlik, Carol
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Read Online
- Desulfurization-oxygenation of chiral 1,3-thiazolidine-2-thiones and 1,3-oxazolidine-2-thiones using propylene oxide and microwave irradiation
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An efficient method for the desulfurization-oxygenation of 1,3-thiazolidine-2-thiones and 1,3-oxazolidine-2-thiones using propylene oxide and employing microwave irradiation is described. This strategy of oxygenation of the thiocarbonyl group provides an attractive methodology to prepare chiral 1,3-thiazolidin-2-ones and 1,3-oxazolidin-2-ones from the corresponding precursors in good yields. Copyright
- Minor-Villar, Leticia,Tello-Aburto, Rodolfo,Olivo, Horacio F.,Fuentes, Aydee,Romero-Ortega, Moises
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Read Online
- Completely stereocontrolled aldol reaction of chiral ?2-amino acids
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A general protocol to independently access stereoisomerically pure ?2 a?2-hydroxy-?2-amino acid derivatives that is based on dibutylboron triflate-mediated aldol reaction of suitably protected ?2-amino acids bearing chiral oxazolidinone auxiliary is reported. The method smoothly afforded syn-aldol (?±,?2 a?2-syn) products in pure form and excellent isolated yield. Both ?±,?2-syn and ?±,?2-anti isomers are readily accessible solely through the choice of the oxazolidinone chirality. This method allows for the preparation of stereoisomeric ?2 a?2-hydroxy-?2-amino acid derivatives that were previously unreported.
- Gazvoda, Martin,Hoferl-Prantz, Kathrin,Barth, Roland,Felzmann, Wolfgang,Pevec, Andrej,Ko??mrlj, Janez
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Read Online
- Chiral Dipole-Stabilized Anions: Experiment and Theory in Nonbenzylic Systems. 100percent Stereoselective Deprotonation and Two-Electron vs Single-Electron Transfer in the Chemistry of Lithium and Copper Piperidinooxazolines
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A chiral oxazoline derived from valine mediates the 100percent stereoselective deprotonation of the 2-position of piperidine, forming a single diastereomer organolithium, which is dipole-stabilized.The organolithium species undergoes either two electron or single electron transfer processes, but the latter predominate for most electrophiles.The corresponding cuprates undergo only single electron transfer processes.MNDO calculations indicate little difference in energy between most of the conformational and stereoisomers of the organolithium, suggesting that the single organolithium diastereomer is formed under kinetic control.Mechanistic rationales for the unprecedented deprotonation, as well as the single electron transfer processes, are presented.
- Gawley, Robert E.,Hart, Georgina C.,Bartolotti, Libero J.
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Read Online
- Efficient Access to Chiral 2-Oxazolidinones via Ni-Catalyzed Asymmetric Hydrogenation: Scope Study, Mechanistic Explanation, and Origin of Enantioselectivity
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Cheap transition metal Ni-catalyzed asymmetric hydrogenation of 2-oxazolones was successfully developed, which provided an efficient synthetic strategy to prepare various chiral 2-oxazolidinones with 95%-99% yields and 97%->99% ee. The gram-scale hydrogenation could be proceeded well with >99% ee in the presence of low catalyst loading (up to 3350 TON). This Ni-catalyzed hydrogenation protocol demonstrated great synthetic utility, and the chiral 2-oxazolidinone product was easily converted to a variety of other important molecules in good yields and without loss of ee values, such as chiral dihydrothiophene-2(3H)-thione, amino alcohol, oxazoline ligand, and allenamide. Moreover, a series of deuterium labeling experiments, control experiments, and DFT calculations were conducted to illustrate a reasonable catalytic mechanism for this Ni-catalyzed asymmetric hydrogenation, which involved a tautomerization between the enamine and its isomer imine and then went through asymmetric 1,2-addition of Ni(II)-H to the preferred imine.
- Dong, Xiu-Qin,Liu, Yuanhua,Wang, Heng,Wang, Minyan,Yang, Xuanliang,Yi, Zhiyuan,Yin, Congcong,Zhang, Xumu
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p. 11153 - 11161
(2020/11/23)
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- Synthesis of a diastereomer of the marine macrolide lytophilippine A
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The synthesis of a diastereomer of lytophilippine A required 22 longest linear steps using known building blocks. Cross-metathesis/asymmetric aldol addition and regioselective esterification/ring-closing metathesis served as efficient combi tools for scaffold construction. Detailed NMR investigations in different solvent (systems) provide evidence for a deep-seated configurational misassignment of the molecule named lytophilippine A.
- Klüppel, André,Gille, Annika,Karayel, Ceren Ester,Hiersemann, Martin
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supporting information
p. 2421 - 2425
(2019/03/29)
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- PROCESS FOR PREPARING OPTICALLY PURE (R)-4-N-PROPYL-DIHYDROFURAN-2(3H)-ONE
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The present invention discloses a process for preparing optically pure (R)-4-n-propyl-dihydrofuran-2(3H)-one, belonging to the field of chemical synthesis. According to the process, optically pure (S)-3-n-pentanoyl-4-substituted oxazol-2-one is used as a starting material, and after alkylation, reduction, cyano hydrolysis, lactonization, the product optically pure (R)-4-n-propyl-dihydrofuran-2(3H)-one is given. The preparation process has the advantages of easy availability of raw materials, low price, high yield, high optical purity of product, simple reaction conditions and simple operations.
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Paragraph 0105-0106
(2019/12/10)
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- Simple preparation method of N-acyl compound
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The invention relates to a simple preparation method of an N-acyl compound. The simple preparation method comprises the specific steps that an amine compound and R-OCF3 are mixed in a solvent and react for 1 min-48 h at -80-100 DEG C, after the reaction is completed, water is added for quenching, and column separation and purification or recrystallization and purification are carried out to obtainthe N-acyl compound. According to the simple preparation method of the N-acyl compound, the characteristic that a substance containing trifluorooxygen groups can be decomposed in situ to produce fluorophosgene is utilized, and the substance directly reacts with the amine compound to achieve rapid N-carbonylation of an amines substrate and efficiently prepare a urea derivative and a carbamyl fluoride compound. The simple preparation method of the N-acyl compound has the advantages that the operation is simple, the reaction time is short, the application range of the substrate is wide, no catalysts or additives need to be used, the raw materials are easy to obtain, the product yield is high, the purification is easy, and the required compound can be obtained by using a column chromatographyisolation method or recrystallization.
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Paragraph 0049-0051
(2019/07/04)
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- Concise and Additive-Free Click Reactions between Amines and CF3SO3CF3
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Trifluoromethyl trifluoromethanesulfonate has proved to be an excellent reservoir of difluorophosgene and a promising click ligation for amines in the preparation of urea derivatives, heterocycles, and carbamoyl fluorides under metal- and additive-free conditions. The reactions are rapid, efficient, selective, and versatile, and can be performed in benign solvents, giving products in excellent yields with minimal efforts for purification. The characteristics of the reactions meet the requirements of a click reaction. The use of trifluoromethyl trifluoromethanesulfonate as a click reagent is advantageous over other “CO” sources (e.g., TsOCF3, PhCO2CF3, CsOCF3, AgOCF3, and triphosgene) because this reagent is readily accessible; easy to scale up; and highly reactive, even under metal- and additive-free conditions. It is anticipated that CF3SO3CF3 will be increasingly as important as SO2F2 as a click agent in future drug design and development.
- Song, Hai-Xia,Han, Zhou-Zhou,Zhang, Cheng-Pan
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supporting information
p. 10907 - 10912
(2019/08/02)
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- Advances and Setbacks in the Total Synthesis of the Fungal Metabolite Curvicollide C: Synthesis and Elaboration of Non-Aldol Stereotriads from Gosteli-Type Allyl Vinyl Ethers
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Advances and setbacks are reported in regard to the asymmetric total synthesis of the fungal metabolite curvicollide C relying on a synthetic strategy that exploits non-aldol stereotriads as chiral building blocks. A catalytic asymmetric Gosteli-Claisen rearrangement, a two-step aldehyde-to-alkyne-homologation, and a Julia-Kocienski olefination served as key C/C-connecting transformations.
- K?rner, Marleen,Hiersemann, Martin
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p. 2466 - 2482
(2016/07/28)
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- Combining Low-Pressure CO2 Capture and Hydrogenation to Form Methanol
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This paper describes a novel approach to CO2 hydrogenation, in which CO2 capture with aminoethanols at low pressure is coupled with hydrogenation of the captured product, oxazolidinone, directly to MeOH. In particular, (2-methylamino)ethanol or valinol captures CO2 at 1-3 bar in the presence of catalytic Cs2CO3 to give the corresponding oxazolidinones in up to 65-70 and 90-95% yields, respectively. Efficient hydrogenation of oxazolidinones was achieved using PNN pincer Ru catalysts to give the corresponding aminoethanol (up to 95-100% yield) and MeOH (up to 78-92% yield). We also have shown that both CO2 capture and oxazolidinone hydrogenation can be performed in the same reaction mixture using a simple protocol that avoids intermediate isolation or purification steps. For example, CO2 can be captured by valinol at 1 bar with Cs2CO3 catalyst followed by 4-isopropyl-2-oxazolidinone hydrogenation in the presence of a bipy-based pincer Ru catalyst to produce MeOH in 50% yield after two steps.
- Khusnutdinova, Julia R.,Garg, Jai Anand,Milstein, David
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p. 2416 - 2422
(2015/04/14)
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- Copper(II)-catalysed oxidative carbonylation of aminols and amines in water: A direct access to oxazolidinones, ureas and carbamates
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Copper(II) chloride catalyses the oxidative carbonylation of aminols, amine and alcohols to give 2-oxazolidinones, ureas and carbamates. Reaction proceeds smoothly in water under homogeneous conditions (Ptot = 4 MPa; PO2 = 0.6 MPa, PCO), at 100°C in relatively short reaction times (4 h) and without using bases or any other additives. This methodology represents an economic and environmentally benign non-phosgene alternative for the preparation of these three important N-containing carbonyl compounds.
- Casiello, Michele,Iannone, Francesco,Cotugno, Pietro,Monopoli, Antonio,Cioffi, Nicola,Ciminale, Francesco,Trzeciak, Anna M.,Nacci, Angelo
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- Easy access to evans' oxazolidinones. Stereoselective synthesis and antibacterial activity of a new 2-oxazolidinone derivative
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An interesting new approach was developed for the synthesis of Evans' chiral auxiliaries with excellent yields. In turn, another new stereoselective and efficient strategy has also allowed for the preparation of a 2-oxazolidinone derivative in 34% overall yield from the Morita-Baylis-Hillman adduct. The antibacterial activity of this oxazolidinone was tested against Staphylococcus aureus strains isolated from animals with mastitis infections.
- Diaz, Gaspar,De Freitas, Michelle A.A.,Ricci-Silva, Maria E.,Diaz, Marisa A.N.
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p. 7429 - 7439
(2014/07/08)
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- Amidation of esters with amino alcohols using organobase catalysis
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A catalytic protocol for the base-mediated amidation of unactivated esters with amino alcohol derivatives is reported. Investigations into mechanistic aspects of the process indicate that the reaction involves an initial transesterification, followed by an intramolecular rearrangement. The reaction is highly general in nature and can be extended to include the synthesis of oxazolidinone systems through use of dimethyl carbonate.
- Caldwell, Nicola,Campbell, Peter S.,Jamieson, Craig,Potjewyd, Frances,Simpson, Iain,Watson, Allan J. B.
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p. 9347 - 9354
(2014/12/11)
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- PROCESS FOR THE PREPARATION OF A FLUOROLACTON DERIVATIVE
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A novel process for the preparation of a fluorolactone derivative of the formula (I) and of its acylated derivative of formula (V) wherein R1 stands for a hydroxy protecting group is described. The acylated fluorolactones of formula (V), particularly the benzoyl derivative with R1 =benzyl are important precursors for the synthesis of prodrug compounds which have the potential to be potent inhibitors of the Hepatitis C Virus (HCV) NS5B polymerase.
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Page/Page column 9
(2014/07/23)
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- Catalytic fluoride triggers dehydrative oxazolidinone synthesis from CO2
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Herein, catalytic fluoride (F-) is demonstrated to be a trigger for dehydrative immobilization of atmospheric pressure CO2, such that reaction of CO2 with β-amino alcohols derived from natural amino acids gives optically pure oxazolidinones in high yields. A synergistic combination of fluoride and organosilicon agents (e.g., Bu4NF + Ph3SiF or siloxanes) enhances the catalytic activity and functional group compatibility. This system lies at the interface between homogenous and heterogeneous catalysis, and may prove useful for the development of recoverable/reusable siloxane-based CO2 immobilization materials. This journal is
- Takada, Yuki,Foo, Siong Wan,Yamazaki, Yusuke,Saito, Susumu
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p. 50851 - 50857
(2015/02/19)
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- Asymmetric synthesis of 3,3,5,5-tetrasubstituted 1,2-dioxolanes: Total synthesis of epiplakinic acid F
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The first enantioselective total synthesis of epiplakinic acid F (1) was achieved through a pivotal step involving a radical-mediated asymmetric peroxidation of vinylcyclopropanes with molecular oxygen to construct highly substituted 1,2-dioxolanes. Subsequent conversions of the chiral 1,2-dioxolanes led to total synthesis of epiplakinic acid F (1) and the confirmation of its absolute configuration. The enantiomer of epiplakinic acid F methyl ester (2) was also prepared. This journal is the Partner Organisations 2014.
- Tian, Xiang-Yin,Han, Jian-Wei,Zhao, Qiong,Wong, Henry N. C.
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supporting information
p. 3686 - 3700
(2014/06/09)
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- Synthesis of salicylic acid-based 1,3,4-oxadiazole derivatives coupled with chiral oxazolidinones: Novel hybrid heterocycles as antitumor agents
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A series of novel salicylic acid-based 1,3,4-oxadiazoles derivatives coupled with chiral oxazolidinones were synthesized to screen for their in vitro antitumor activity against five human cancer cell lines. Some of these compounds showed good antitumor activities with IC50values ranging from 31.19-57.21 μM. Among the tested compounds 11, 15, 19,23,24, and 34 showed broad-spectrum antitumor activity against all the cell lines. In particular, compound 19 revealed remarkable antitumor activity with IC50 = 31.19-41.87 μM. A431 was the most sensitive cell line against all the compounds studied, followed by HeLa, MCF-7, A549 and HepG2. Structures of newly synthesized compounds were confirmed by IR,1 H NMR, 13C NMR and HRMS spectral data
- Murty,Penthala, Raju,Nath, Lekshmi R.,Anto, Ruby John
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p. 1133 - 1142
(2015/03/31)
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- Dehydrative synthesis of chiral oxazolidinones catalyzed by alkali metal carbonates under low pressure of CO2
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Dehydrative synthesis of oxazolidinones from amino alcohols and CO 2 was achieved in the presence of alkali metal carbonates such as Cs2CO3 as catalyst. It is noteworthy that 1 atm of CO 2 is enough for the reaction to proceed and no special dehydrating agent is required in this system. A mechanstic study showed that the OH of amino alcohol acts as nucleophile and the OH in the carbamic acid moiety is liberated during the cyclization process.
- Foo, Siong Wan,Takada, Yuki,Yamazaki, Yusuke,Saito, Susumu
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supporting information
p. 4717 - 4720
(2013/08/23)
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- Explorations of an intramolecular route to pyrrolo[3,4-b]isoxazoles: An unexpected retro-Claisen reaction
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Potential precursors have been prepared for intramolecular 1,3-dipolar cycloaddition to form a pyrrolo[3,4-b]isoxazole. The cycloaddition has not to date been accomplished, however an unexpected retro-Claisen reaction is reported. ARKAT-USA, Inc.
- Jones, Raymond C.F.,Law, Carole C.M.,Elsegood, Mark R.J.
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- N-(diazoacetyl)oxazolidin-2-thiones as sulfur-donor reagents: Asymmetric synthesis of thiiranes from aldehydes
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Sulfur tyranny: Thiiranes, instead of oxiranes, can be obtained in a highly stereoselective manner through the cycloaddition reaction of N-acyl oxazolidine tethered diazo thione compounds with aldehydes catalyzed by RhII. Thus, this reaction provides versatile adducts S functionalized at both the α and β position, with concomitant generation of two contiguous stereocenters. Copyright
- Cano, Israel,G?mez-Bengoa, Enrique,Landa, Aitor,Maestro, Miguel,Mielgo, Antonia,Olaizola, Iurre,Oiarbide, Mikel,Palomo, Claudio
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supporting information
p. 10856 - 10860
(2013/01/15)
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- Synthesis of cyanoacetyl oxazolidinones
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Carefully controlled displacement of chiral chloroacetyl imides with cyanide afforded previously unreported cyanoacetimides in good overall yield. Knoevenagel condensation of the cyanoacetimides to furnish acrylonitriles was also demonstrated. Georg Thiem
- Weeber, Kaitlyn M.,Schwarz, Jacob B.
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experimental part
p. 1993 - 1996
(2012/09/07)
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- Efficient parallel resolution of pentafluorophenyl active esters using quasi-enantiomeric combinations of oxazolidin-2-ones
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The parallel resolution of racemic pentafluorophenyl 2-aryl/ phenylpropanoates and butanoates using an equimolar combination of quasi-enantiomeric Evans oxazolidin-2-ones is discussed. The levels of diastereoselectivity were excellent (>90% de) leading to separable quasi-enantiomeric oxazolidin-2-ones in good yield. This methodology was used to resolve a series of structurally related 2-aryl/phenylpropanoic and butanoic acids.
- Shaye, Najla Al,Chavda, Sameer,Coulbeck, Elliot,Eames, Jason,Yohannes, Yonas
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experimental part
p. 439 - 463
(2011/06/17)
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- Resolution of pentafluorophenyl 2-phenylpropanoate using combinations of quasi-enantiomeric oxazolidin-2-ones
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The kinetic, mutual and parallel resolution of a series of structurally related active esters derived from 2-phenylpropanoic acid using a combination of quasi-enantiomeric oxazolidin-2-ones is discussed.
- Shaye, Najla Al,Benoit, David M.,Chavda, Sameer,Coulbeck, Elliot,Dingjan, Marco,Eames, Jason,Yohannes, Yonas
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experimental part
p. 413 - 438
(2011/06/17)
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- Enantioselective preparation of P-chiral phosphine oxides
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A highly efficient chiral auxiliary-based strategy for the asymmetric synthesis of P-chiral phosphine oxides in >98:2 er has been developed. The methodology involves the highly stereoselective formation of P-chiral oxazolidinones that then undergo displacement with a variety of Grignard reagents to prepare the desired phosphine oxides.
- Adams, Harry,Collins, Rebecca C.,Jones, Simon,Warner, Christopher J. A.
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supporting information; experimental part
p. 6576 - 6579
(2012/01/15)
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- Linear synthesis of chiral cycloSal-pronucleotides
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CycloSal-nucleosyl-phosphate triesters are a known class of highly effective nucleotide prodrugs (pronucleotides) of antivirally active nucleoside analogues. Until recently, the synthesis of these compounds always gave diastereoisomeric mixtures. Then, a convergent route for the stereospecific synthesis of cycloSal-triesters was described to give isomerically pure cycloSal-prodrugs for the treatment of viral diseases. Here, the development of a stereoselective synthesis of these pronucleotides using various chiral auxiliaries is described. In contrast to pyrrolidine- or pyrrolidinone derivatives it was found that a thiazolidine derived from valinol fulfilled all three requirements to act as a suitable chiral moiety, allowing: (i) strong chirality transfer, (ii) the formation of separable diastereoisomeric intermediates, and (iii) a suitable leaving group that allows the introduction of the nucleoside analogue (e.g., d4T) in the final step under mild reaction conditions. The title compounds were obtained with very high diastereoisomeric excesses of more than 95%. The development of a stereoselective route to cycloSal-nucleotides of thymidine and d4T based on the use of various chiral auxiliaries is reported. The target chiralphosphates were obtained with very high diastereoisomeric excesses of more than 95%.
- Morales, Edwuin Hander Rios,Roman, Cristina Arbelo,Thomann, Jens Oliver,Meier, Chris
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scheme or table
p. 4397 - 4408
(2011/10/08)
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- Synthesis of some 2-Oxazolidinones in mild conditions
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One step efficient protocol for the synthesis of 2-oxazolidinones in paste chemical medium is described under microwave activation with 80 % yield.
- Bratulescu, George
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experimental part
p. 929 - 930
(2011/12/15)
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- The enantioselective intramolecular Morita-Baylis-Hillman reaction catalyzed by amino acid-derived phosphinothiourea
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A series of chiral bifunctional phosphinothioureas derived from l-amino acids have been developed to promote the enantioselective intramolecular Morita-Baylis-Hillman reaction. The process afforded the cyclic hydroxyl enones with up to 84% ee and good yields under mild conditions.
- Gong, Jing-Jing,Yuan, Kui,Song, Hong-Liang,Wu, Xin-Yan
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scheme or table
p. 2439 - 2443
(2010/06/12)
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- Carbon dioxide as a carbonylating agent in the synthesis of 2-oxazolidinones, 2-oxazinones, and cyclic ureas: Scope and limitations
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Carbon dioxide can be used as a convenient carbonylating agent in the synthesis of 2-oxazolidinones, 2-oxazinones, and cyclic ureas. The transient carbamate anion generated by treating a primary or secondary amine group in basic media can be activated with phosphorylating agents such as Diphenylphosphoryl azide (DPPA) and Diphenyl chlorophosphate (DPPCl) but also with other types of electrophiles such as SOCl2, TsCl, or AcCl. The intramolecular trapping of the activated carbamate by a hydroxyl group leads to the formation of 2-oxazolidinones or 2-oxazinones in good to excellent yields. This methodology was successfully applied to the synthesis of cyclic ureas up to 7-membered rings from the corresponding diamines.
- Paz, Jairo,Perez-Balado, Carlos,Iglesias, Beatriz,Munoz, Luis
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supporting information; experimental part
p. 3037 - 3046
(2010/07/15)
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- Development of bifunctional aza-bis(oxazoline) copper catalysts for enantioselective henry reaction
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Base-functionalized aza-bis(oxazoline) ligands were prepared to explore the concept of dual activation through the Lewis acid and a tethered tertiary amine base. The catalytic activity of the Cu complex was evaluated for the asymmetric Henry reaction. Compared with a corresponding unfunctionalized copper complex with external 1-benzyl-4-ethylpiperazine base, the ethylpiperazine- functionalized aza-bis(oxazoline) copper catalyst resulted in rate acceleration (2.5 times) as well as improved enantioselectivity (72% ee vs 92% ee).
- Lang, Kai,Park, Jongwoo,Hong, Sukwon
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supporting information; experimental part
p. 6424 - 6435
(2010/12/19)
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- Carbonylation with CO2 and phosphorus electrophiles: A convenient method for the synthesis of 2-oxazolidinones from 1,2-amino alcohols
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2-Oxazolidinones were prepared in good yields from 1,2-amino alcohols and CO2 in the presence of tetramethyl-phenylguanidine (PhTMG) as a base and a variety of phosphorus electrophiles under mild conditions. This procedure is advantageous over previous methodologies and relies on a novel carbonylation procedure that utilizes nontoxic CO2 and phosphorus electrophiles. Georg Thieme Verlag Stuttgart.
- Paz, Jairo,Pérez-Balado, Carlos,Iglesias, Beatriz,Mu?oz, Luis
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scheme or table
p. 395 - 398
(2009/08/09)
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- Asymmetric synthesis of amlnocyclopropanes and N-cyclopropylamino alcohols through direct amidocyclopropanation of alkenes using chiral organozinc carbenoids
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Chiral N-(diethoxymethyl)oxazolidinones, prepared from the corresponding oxazolidinones by heating in trielhyl orthoformate, can be used as organozinc carbenoid precursors for the direct enantioselective amidocyclopropanation of alkenes. The reaction is successful with a wide range of oxazolidinones and alkenes and proceeds with moderate to excellent yield and stereoselectivity. In most cases the trans/exo amidocyclopropane product, is favoured, although certain cyclic alkenes such as indene favour the formation of the endo cyclopropane. The products can be readily elaborated to produce cyclopropylamino alcohols and amino acids. Wiley-VCH Verlag GmbH & Co. KGaA.
- Begis, Guillaume,Cladingboel, David E.,Jerome, Laure,Motherwell, William B.,Sheppard, Tom D.
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experimental part
p. 1532 - 1548
(2009/09/08)
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- On the structure and chiroptical properties of (S)-4-isopropyl-oxazolidin-2-one
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The specific rotation of (S)-4-isopropyl-oxazolidin-2-one is extremely solvent dependent. In chloroform it is dextrorotatory {[α]D26 = + 15.5 (c 5.2, CHCl3)}, whereas in ethanol it is levorotatory {[α]D26 = - 16.1 (c 5.2, EtOH)}.
- Benoit, David,Coulbeck, Elliot,Eames, Jason,Motevalli, Majid
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p. 1068 - 1077
(2008/09/20)
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- PROCESS FOR STEREOSELECTIVE PREPARATION OF 4-BMA USING A CHIRAL AUXILIARY
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The present invention relates to a process for preparing (3R,4S)-3-[[[R]-V-t- butyldimethylsilyloxy] ethyl] -4- [(/?)- l"-carboxyethyl]-2-azetidinone [4-BMA: formula (6)], a key intermediate for the synthesis of carbapenem and penem antibiotics. Specifically, the present invention relates to a process comprising first, the preparation of a chiral auxiliary from cheap L-Valinol, and then the preparation of 4-BMA in high yield and high selectivity, under industrially mild conditions.
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Page/Page column 13
(2008/12/08)
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- Samarium diiodide as an efficient catalyst for the conversion of N-acyloxazolidinones into esters
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The transformation of N-acyloxazolidinones into esters is readily performed using catalytic amounts of samarium diiodide in tetrahydrofuran at room temperature. This method allows the isolation of various esters without racemization in the case of scalemi
- Magnier-Bouvier, Caroline,Reboule, Iréna,Gil, Richard,Collin, Jacqueline
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scheme or table
p. 1211 - 1215
(2009/04/06)
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- Parallel kinetic resolution of racemic oxazolidinones using quasi-enantiomeric active esters
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Racemic Evans' oxazolidinones were efficiently resolved using a combination of quasi-enantiomeric profens. The levels of stereocontrol were high, leading to products with predictable configurations.
- Boyd, Ewan,Coulbeck, Elliot,Coumbarides, Gregory S.,Chavda, Sameer,Dingjan, Marco,Eames, Jason,Flinn, Anthony,Motevalli, Majid,Northen, Julian,Yohannes, Yonas
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p. 2515 - 2530
(2008/03/15)
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- A novel and efficient (NHC)CuI (NHC = N-heterocyclic carbene) catalyst for the oxidative carbonylation of amino compounds
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Oxidative carbonylation of amino compounds to prepare corresponding 2-oxazolidinones, ureas, and carbamates selectively in the presence of (NHC)CuI without any additives was firstly achieved in good yields and selectivities.
- Zheng, Shuzhan,Li, Fuwei,Liu, Jianming,Xia, Chungu
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p. 5883 - 5886
(2008/02/09)
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- Synthesis of 2-oxazolidinones by salen-Co-complexes catalyzed oxidative carbonylation of β-amino alcohols
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2-Oxazolidinones are synthesized in high yield by oxidative carbonylation of β-amino alcohols using salen-Co(II)/NaI or salen-Co(III)-I as a catalyst and using CO as the carbonyl source. Studies of functional group compatibility using a series of substituted salen-Co(II) or salen-Co(III)-I complexes demonstrate a broad tolerance of functionality during the carbonylation reaction.
- Liu, Jian-Ming,Peng, Xin-Gao,Liu, Jian-Hua,Zheng, Shu-Zhan,Sun, Wei,Xia, Chun-Gu
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p. 929 - 932
(2008/02/04)
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- Efficient synthesis of oxazolidin-2-one via (chitosan-Schiff base)cobalt(II)-catalyzed oxidative carbonylation of 2-aminoalkan-1-ols
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The (chitosan-Schiff base)cobalt(II) complex was found to be an efficient catalyst for the oxidative carbonylation (CO/O2) of 2-aminoalkan-1-ols 1 to give oxazolidin-2-ones 2, in the presence of NaI. The effects of promoters, temperature, solvents, and other reaction conditions were investigated in this study.
- Liu, Jianming,Sun, Wei,Zheng, Shuzhan,Xia, Chungu
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p. 1593 - 1598
(2008/02/09)
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- Remarkably efficient charcoal-promoted ring-closing carbonylations
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An efficient, versatile and practical gram-scale preparation of oxazolidinone, imidazolidinone and dioxolanone is achieved. Georg Thieme Verlag Stuttgart.
- Alouane, Nacira,Boutier, Audrey,Baron, Cyriella,Vrancken, Emmanuel,Mangeney, Pierre
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p. 885 - 889
(2007/10/03)
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- Investigations into the parallel kinetic resolution of 2-phenylpropanoyl chloride using quasi-enantiomeric oxazolidinones
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The resolution of 2-phenylpropanoyl chloride using an equimolar combination of quasi-enantiomeric oxazolidinones is discussed. The levels of diastereoselectivity were found to be dependent upon the structural nature of the metallated oxazolidinone, temperature and metal counter-ion.
- Chavda, Sameer,Coulbeck, Elliot,Coumbarides, Gregory S.,Dingjan, Marco,Eames, Jason,Ghilagaber, Stephanos,Yohannes, Yonas
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p. 3386 - 3399
(2007/10/03)
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- Kinetic resolution of 2-oxazolidinones via catalytic, enantioselective N-acylation
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Kinetic resolution of racemic 2-oxazolidinones via catalytic, enantioselective N-acylation has been achieved for the first time and with outstanding selectivities. Copyright
- Birman, Vladimir B.,Jiang, Hui,Li, Ximin,Guo, Lei,Uffman, Eric W.
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p. 6536 - 6537
(2007/10/03)
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- METHOD FOR SYNTHESISING OPTICALLY ACTIVE PIPERIDINES BY THE HYDROGENATION OF OPTICALLY ACTIVE PYRIDINES
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The invention relates to a method for preparing optically active piperidines by the hydrogenation of pyridines using a suitable catalyst. Said method enables the preparation of a plurality of piperidine derivatives with high optical purity and in high yields.
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Page/Page column 10; 11
(2010/02/12)
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- Chemically modified mutant serine hydrolases show improved catalytic activity and chiral selectivity
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This invention provides novel chemically modified mutant serine hydrolases that catalyze a transamidation and/or a transpeptidation and/or a transesterification reaction. The modified serine hydrolases have one or more amino acid residues in a subsite replaced with a cysteine, wherein the cysteine is modified by replacing the thiol hydrogen in the cysteine with a substituent group providing a thiol side chain comprising a moiety selected from the group consisting of a polar aromatic substituent, an alkyl amino group with a positive charge, and a glycoside. In particularly preferred embodiments, the substitutents include an oxazolidinone, a C1 to C15 alkyl amino group with a positive charge, or a glycoside.
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- Construction of C-S bonds with a quaternary stereocenter through a formal Michael reaction: Asymmetric synthesis of tertiary thiols
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Quaternary stereocenters that bear a sulfur substituent can be created with nearly perfect stereocontrol through an intramolecular Michael-type process. Lewis acids (L.A.) accelerate the intramolecular sulfur-atom transfer from the oxazolidine-2-thione functionality to the β carbon atom of the β,β-disubstituted enoyl moiety, whereas the chirality of the oxazolidine-2-thione portion controls reaction stereochemistry (see scheme).
- Palomo, Claudio,Oiarbide, Mikel,Dias, Flavia,Lopez, Rosa,Linden, Anthony
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p. 3307 - 3310
(2007/10/03)
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- Highly diastereoselective mannich-type reactions of chiral N-acylhydrazones
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The Lewis acid-mediated addition of silyl enolates to easily accessible homochiral N-acylhydrazones derived from 3-amino-2-oxazolidinones proceeded in yields up to 71% and diastereomeric ratios of 99:1. In most cases, optimal reaction conditions entailed the simple use of ZnCl2 in acetonitrile at room temperature. Hydrazones derived from phenyl-, isopropyl-, and benzyl-substituted 2-oxazolidinones were examined in the reaction in terms of yield and diastereoselectivity. The facile SmI2-mediated N-N bond cleavage of the formed hydrazines was demonstrated yielding a β-amino acid derivative. Hence, the overall reaction sequence constitutes an efficient asymmetric Mannich-type reaction. The sense of diastereoselectivity was explained by a preferential attack on the less shielded Si face of the chiral hydrazones and confirmed by means of X-ray crystallography.
- Jacobsen, Mikkel F.,Ionita, Liviu,Skrydstrup, Troels
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p. 4792 - 4796
(2007/10/03)
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- Chemical fixation of carbon dioxide co-catalyzed by a combination of Schiff bases or phenols and organic bases
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Binaphthyldiamino, ethyldiamino and cyclohexyldiamino Schiff bases can catalyze the reaction of epoxides with carbon dioxide in the presence of catalytic amounts of various organic bases to give the corresponding cyclic carbonates in high yields. The simplest binaphthyldiamino Schiff base, derived from the reaction of binaphthyldiamine with salicylaldehyde, gave the highest yield of cyclic carbonate. This catalytic system can be further simplified by use of a phenol instead of the Schiff base to give the corresponding cyclic carbonates in high yields as well. Mechanistic insights were obtained based on a deuterium labeling experiment, The reaction of aziridines with CO2 and epoxide with CS2 were also examined under the same reaction conditions. Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004.
- Shen, Yu-Mei,Duan, Wei-Liang,Shi, Min
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p. 3080 - 3089
(2007/10/03)
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- Synthesis of 2-oxazolidinone catalyzed by palladium on charcoal: A novel and highly effective heterogeneous catalytic system for oxidative cyclocarbonylation of β-aminoalcohols and 2-aminophenol
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Oxidative cyclocarbonylation of β-aminoalcohols and 2-aminophenol to synthesize corresponding 2-oxazolidinones catalyzed by a Pd/C-I2 heterogeneous catalytic system has been developed which gave excellent selectivity and high turnover frequency (TOF) values 15 times larger than the best results previously reported. The catalyst could be reused for five times almost without losing its catalytic activity and selectivity. The effects of promoters, pretreatment, solvents, and reaction conditions have been investigated.
- Li, Fuwei,Xia, Chungu
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p. 542 - 546
(2007/10/03)
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- Mechanistic study on nitrosation-deaminocyclization of mono-carbamoylated vicinal amino alcohols and diols: a new preparative in situ formation of ethanediazo hydroxide for the ethylation of carboxylates under mild conditions
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While the cyclization of N-carbamoylamino alcohols into oxazolidinones via the activation with NO(1+) underwent smoothly, we found that similar reactions of vicinal diol monocarbamates were very slow. Mechanistic studies by means of time-resolved IR measurements of the former reaction suggested that the initial O-nitrosation was the rate-determining step. Indeed, the introduction of an ethyl group on the nitrogen terminus of diol monocarbamate promoted the desired cyclic carbonate formation. The concomitantly formed ethanediazo hydroxide, the precursor of the protonated form of diazoethane, was evidenced by trapping with p-nitrobenzoic acid as an ethyl ester. The formation of ethyl ester accelerates the reaction in an irreversible manner. Based on an elaboration of the substrates and reaction conditions, 2,3-dimethyl-2,3-butanediol mono-N-ethyl-N-nitrosocarbamate, which is easily prepared in situ from the corresponding ethylcarbamate and t-butyl nitrite, was developed as a new ethylation reagent of various carboxylic acids under mild conditions.
- Suzuki, Masumi,Sugai, Takeshi
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p. 1217 - 1228
(2007/10/03)
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- A simple method removing 2-oxazolidinone and 2-hydroxyethylamine auxiliaries in methoxide-carbonate systems for synthesis of planar-chiral nicotinate
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A facile and practical removal of 2-oxazolidinone and 2-hydroxyethylamine auxiliaries was accomplished by treating the corresponding N-acyl-2-oxazolidinone and N-(2-hydroxyethyl)amide derivatives in simple methoxide-carbonate systems. The presence of excess DMC (dimethyl carbonate) accelerates the N-acyl bond cleavage for those substrates under mild reaction conditions, and the present method was found to be useful especially for the synthesis of planar-chiral nicotinate.
- Kanomata, Nobuhiro,Maruyama, Satoshi,Tomono, Katsuhito,Anada, Shinnosuke
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p. 3599 - 3603
(2007/10/03)
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