17016-83-0Relevant academic research and scientific papers
Bis(o-nitrophenyl) carbonate as a new reagent for the synthesis of chiral oxazolidin-2-ones
Simon, Monika,Micle, Andreea,Badea, Valentin,Csunderlik, Carol
, p. 2633 - 2639 (2009)
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.
Desulfurization-oxygenation of chiral 1,3-thiazolidine-2-thiones and 1,3-oxazolidine-2-thiones using propylene oxide and microwave irradiation
Minor-Villar, Leticia,Tello-Aburto, Rodolfo,Olivo, Horacio F.,Fuentes, Aydee,Romero-Ortega, Moises
, p. 2835 - 2839 (2012)
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
Completely stereocontrolled aldol reaction of chiral ?2-amino acids
Gazvoda, Martin,Hoferl-Prantz, Kathrin,Barth, Roland,Felzmann, Wolfgang,Pevec, Andrej,Ko??mrlj, Janez
, p. 512 - 515 (2015)
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.
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
Gawley, Robert E.,Hart, Georgina C.,Bartolotti, Libero J.
, p. 175 - 181 (1989)
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.
Efficient Access to Chiral 2-Oxazolidinones via Ni-Catalyzed Asymmetric Hydrogenation: Scope Study, Mechanistic Explanation, and Origin of Enantioselectivity
Dong, Xiu-Qin,Liu, Yuanhua,Wang, Heng,Wang, Minyan,Yang, Xuanliang,Yi, Zhiyuan,Yin, Congcong,Zhang, Xumu
, p. 11153 - 11161 (2020/11/23)
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.
PROCESS FOR PREPARING OPTICALLY PURE (R)-4-N-PROPYL-DIHYDROFURAN-2(3H)-ONE
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Paragraph 0105-0106, (2019/12/10)
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.
Synthesis of a diastereomer of the marine macrolide lytophilippine A
Klüppel, André,Gille, Annika,Karayel, Ceren Ester,Hiersemann, Martin
supporting information, p. 2421 - 2425 (2019/03/29)
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.
Simple preparation method of N-acyl compound
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Paragraph 0049-0051, (2019/07/04)
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.
Concise and Additive-Free Click Reactions between Amines and CF3SO3CF3
Song, Hai-Xia,Han, Zhou-Zhou,Zhang, Cheng-Pan
supporting information, p. 10907 - 10912 (2019/08/02)
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.
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
K?rner, Marleen,Hiersemann, Martin
, p. 2466 - 2482 (2016/07/28)
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.
