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Search for "enantiomeric purity" in Full Text gives 75 result(s) in Beilstein Journal of Organic Chemistry.

Reactions of acryl thioamides with iminoiodinanes as a one-step synthesis of N-sulfonyl-2,3-dihydro-1,2-thiazoles

  • Vladimir G. Ilkin,
  • Pavel S. Silaichev,
  • Valeriy O. Filimonov,
  • Tetyana V. Beryozkina,
  • Margarita D. Likhacheva,
  • Pavel A. Slepukhin,
  • Wim Dehaen and
  • Vasiliy A. Bakulev

Beilstein J. Org. Chem. 2025, 21, 1397–1403, doi:10.3762/bjoc.21.104

Graphical Abstract
  • yields of 1,2-thiazoles 3aa–ae are slightly lower (70 vs 78%) than by method A. We also investigated the effect of chiral catalysts or ligands in the reaction of thioamide 1a with 2a; however, we were unable to achieve high enantiomeric purity of product 3aa (see Supporting Information File 1, Table S1
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Published 10 Jul 2025

New advances in asymmetric organocatalysis II

  • Radovan Šebesta

Beilstein J. Org. Chem. 2025, 21, 766–769, doi:10.3762/bjoc.21.60

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  • ´s quaternary ammonium salts provided the corresponding substituted azlactones comprising a quaternary stereogenic center with the highest enantiomeric purity [21]. A contribution by Chowdhury and Dubey further underscored the importance of heterocyclic moieties in chiral compounds. Their article
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Published 15 Apr 2025

Asymmetric synthesis of fluorinated derivatives of aromatic and γ-branched amino acids via a chiral Ni(II) complex

  • Maurizio Iannuzzi,
  • Thomas Hohmann,
  • Michael Dyrks,
  • Kilian Haoues,
  • Katarzyna Salamon-Krokosz and
  • Beate Koksch

Beilstein J. Org. Chem. 2025, 21, 659–669, doi:10.3762/bjoc.21.52

Graphical Abstract
  • chiral nickel complexes. In recent years, the Soloshonok working group demonstrated the synthesis of non‑natural amino acids using the corresponding chiral Ni(II) complex [7]. In addition to the high enantiomeric purity of the corresponding products, the scale of the reaction, which extends into the
  • hectogram range, is a major strength of this method. In this context, Han et al. could show that the trifluorinated variant of α-aminobutyric acid, trifluoroethylglycine (TfeGly), can be synthesized on a 100 g scale with great enantiomeric purity [8]. The critical step here is the alkylation of the Ni(II
  • h), and the subsequent fluorenylmethoxycarbonyl (Fmoc) protection with FmocOsu led to the formation of the desired fluorinated amino acids. Here, Fmoc-[2.3.5.6F]TfMePhe (2) was isolated in a yield of 67% and a good enantiomeric purity of 90% ee. Fmoc-bisTfMePhe (3) was obtained even in a
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Published 21 Mar 2025

Organocatalytic kinetic resolution of 1,5-dicarbonyl compounds through a retro-Michael reaction

  • James Guevara-Pulido,
  • Fernando González-Pérez,
  • José M. Andrés and
  • Rafael Pedrosa

Beilstein J. Org. Chem. 2025, 21, 473–482, doi:10.3762/bjoc.21.34

Graphical Abstract
  • favored, preserving the (3S,4R)-1 untransformed and avoiding the equilibrium reversal towards the formation of the Michael adduct, thereby preserving the enantiomeric purity of the isolated product. To investigate the scope of the reaction, we extended our kinetic resolution study to a set of 5
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Published 03 Mar 2025

Recent advances in organocatalytic atroposelective reactions

  • Henrich Szabados and
  • Radovan Šebesta

Beilstein J. Org. Chem. 2025, 21, 55–121, doi:10.3762/bjoc.21.6

Graphical Abstract
  • products 89 and their subsequent oxidation with DDQ provided axially chiral quinolines 90 (Scheme 29) [53]. Good retention of the stereoinformation acquired in the first transformation, moderate to excellent yields and consistently high degrees of enantiomeric purity were achieved. The reaction could also
  • , adding a hydroxy group to the benzene ring of indoles 111 and reacting them with tosyl-protected iminoquinone 109 with the help of CPA C30 led to the shift in regioselectivity providing different axially chiral products 113. All products were obtained with high degree of enantiomeric purity as well as
  • positions 6 and 7, but the best results were consistently achieved by exchanging the hydrogen in position 8. Such products along with the ones containing various butyl, methyl, and ethyl esters on the indolizine ring were obtained in moderate to good yields with repeatedly high enantiomeric purity of 97
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Published 09 Jan 2025

Hypervalent iodine-mediated intramolecular alkene halocyclisation

  • Charu Bansal,
  • Oliver Ruggles,
  • Albert C. Rowett and
  • Alastair J. J. Lennox

Beilstein J. Org. Chem. 2024, 20, 3113–3133, doi:10.3762/bjoc.20.258

Graphical Abstract
  • instead proceeded with addition of dichloro(pyridine-2-carboxylato)gold(III) complex in combination with silver triflimide, AgNTf2. A range of β-fluoroazepanes 7 were successfully synthesised with high enantiomeric purity in good yields. A mechanism for the synthesis of β-fluorinated piperidines was
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Published 28 Nov 2024

Negishi-coupling-enabled synthesis of α-heteroaryl-α-amino acid building blocks for DNA-encoded chemical library applications

  • Matteo Gasparetto,
  • Balázs Fődi and
  • Gellért Sipos

Beilstein J. Org. Chem. 2024, 20, 1922–1932, doi:10.3762/bjoc.20.168

Graphical Abstract
  • acids with high enantiomeric purity [23]. The synthesis of formally glycine-derived tertiary α-aryl-amino acids is much less developed. The most common strategy for obtaining these substrates is by lithiation of an aromatic ring followed by coupling with a glycine derivative (Scheme 1a). For example
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Published 08 Aug 2024

Evaluation of the enantioselectivity of new chiral ligands based on imidazolidin-4-one derivatives

  • Jan Bartáček,
  • Karel Chlumský,
  • Jan Mrkvička,
  • Lucie Paloušová,
  • Miloš Sedlák and
  • Pavel Drabina

Beilstein J. Org. Chem. 2024, 20, 684–691, doi:10.3762/bjoc.20.62

Graphical Abstract
  • , the other afforded the nitroaldols with ee values of 60–90%. Finally, the complexes of ligands with cis-cis configuration (Ic and IIc) were evaluated. These catalyst are the most efficient catalysts, producing nitroaldols with very high enantiomeric purity (approx. 90–95% ee). This finding contrasts
  • pyridine to imidazole lowered the reaction rate but did not alter the critical role of configuration at position 2 in determining the enantiomeric purity of the final product. Furthermore, the study of “proline-type” derivative IV underscored the importance of position 2 in chirality transfer, although
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Published 02 Apr 2024

Application of N-heterocyclic carbene–Cu(I) complexes as catalysts in organic synthesis: a review

  • Nosheen Beig,
  • Varsha Goyal and
  • Raj K. Bansal

Beilstein J. Org. Chem. 2023, 19, 1408–1442, doi:10.3762/bjoc.19.102

Graphical Abstract
  • improvement in the enantiomeric purity of the product (>98% conv., 85.5:14.5 er) was achieved while using the naphthyl-substituted salt 163 (Scheme 64). Besides, a highly enantioselective catalytic hydroboration could be achieved from several exocyclic 1,1-disubstituted alkenes 164; in this transformation
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Published 20 Sep 2023

Enolates ambushed – asymmetric tandem conjugate addition and subsequent enolate trapping with conventional and less traditional electrophiles

  • Péter Kisszékelyi and
  • Radovan Šebesta

Beilstein J. Org. Chem. 2023, 19, 593–634, doi:10.3762/bjoc.19.44

Graphical Abstract
  • enantiomeric purity. Further transformations of the products were demonstrated in several examples, including reduction, acidic deprotection and subsequent base-mediated cyclization, or Baeyer–Villiger oxidation. At about the same time, Huang and co-workers have developed similar asymmetric tandem sequences
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Published 04 May 2023

Combretastatins D series and analogues: from isolation, synthetic challenges and biological activities

  • Jorge de Lima Neto and
  • Paulo Henrique Menezes

Beilstein J. Org. Chem. 2023, 19, 399–427, doi:10.3762/bjoc.19.31

Graphical Abstract
  • , overall yield of 29% from 52) (Scheme 15). Using this strategy, combretastatin D-1 (1) was obtained in an enantiomeric purity of 96%, making it possible to establish the absolute configuration of the epoxide. Further, X-ray crystallographic analysis corroborated with the results obtained by Rychnovsky and
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Published 29 Mar 2023

The stereochemical course of 2-methylisoborneol biosynthesis

  • Binbin Gu,
  • Anwei Hou and
  • Jeroen S. Dickschat

Beilstein J. Org. Chem. 2022, 18, 818–824, doi:10.3762/bjoc.18.82

Graphical Abstract
  • stereoisomers (5:2) that were separated by column chromatography (Scheme 2). Reduction of (E)-3 with DIBAl-H gave 2-methylgeraniol (4) that was converted under Sharpless conditions [36] into the epoxides (2R,3R)-5a using ᴅ-(−)-diisopropyl tartrate (DIPT) and (2S,3S)-5b with ʟ-(−)-DIPT. The enantiomeric purity
  • %) (structures are shown in Figure 2). Reproducibility of these results was demonstrated in triplicates. While these data showed that enantiomerically enriched (R)-2-Me-LPP is more efficiently converted into 1 than the enriched S enantiomer, the enantiomeric purity of the substrates was not sufficiently high to
  • with calf intestinal phosphatase (CIP). The thus obtained compounds 6a and 6b were analyzed by gas chromatography on a chiral stationary phase, revealing that the materials were unchanged and still of very high enantiomeric purity (>99% ee, Figure S5 in Supporting Information File 1). Conversion of
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Published 08 Jul 2022

The asymmetric Henry reaction as synthetic tool for the preparation of the drugs linezolid and rivaroxaban

  • Martin Vrbický,
  • Karel Macek,
  • Jaroslav Pochobradský,
  • Jan Svoboda,
  • Miloš Sedlák and
  • Pavel Drabina

Beilstein J. Org. Chem. 2022, 18, 438–445, doi:10.3762/bjoc.18.46

Graphical Abstract
  • -2-one antibiotics only the S-enantiomers are able to block bacterial ribosomes, which leads to the prevention of translation processes in bacteria [9][10]. With regards to these facts, a high enantiomeric purity is one of the fundamental requirements in the production of such pharmaceutical
  • 15 and 19 was also performed with the aim to increase the enantiomeric purity of the corresponding nitroaldol products 21–26. The structural modification consisted in the introduction of different alkyl moieties to the carbamate functional group of the aldehyde intermediates 15–20. As bulky and/or
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Published 14 Apr 2022

Asymmetric organocatalytic Michael addition of cyclopentane-1,2-dione to alkylidene oxindole

  • Estelle Silm,
  • Ivar Järving and
  • Tõnis Kanger

Beilstein J. Org. Chem. 2022, 18, 167–173, doi:10.3762/bjoc.18.18

Graphical Abstract
  • reaction with an electron-donating p-MeO-substituted benzylidene oxindole was very sluggish and did not reach full conversion (Scheme 2, 3m). The product 3m was obtained with only 36% yield and with undetermined enantiomeric purity, since the peaks were not separable in various HPLC methods. Similarly, the
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Published 03 Feb 2022

Regioselective synthesis of methyl 5-(N-Boc-cycloaminyl)-1,2-oxazole-4-carboxylates as new amino acid-like building blocks

  • Jolita Bruzgulienė,
  • Greta Račkauskienė,
  • Aurimas Bieliauskas,
  • Vaida Milišiūnaitė,
  • Miglė Dagilienė,
  • Gita Matulevičiūtė,
  • Vytas Martynaitis,
  • Sonata Krikštolaitytė,
  • Frank A. Sløk and
  • Algirdas Šačkus

Beilstein J. Org. Chem. 2022, 18, 102–109, doi:10.3762/bjoc.18.11

Graphical Abstract
  • hydroxylamine hydrochloride in methanol (Scheme 1). Synthesized compounds 4b–g exhibited optical activity, and the corresponding (R)- or (S)-enantiomers rotated the plane of plane-polarized light in opposite directions. The enantiomeric purity of chiral compounds 4b–g was assessed via chiral HPLC analysis of
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Published 12 Jan 2022

N-Sulfinylpyrrolidine-containing ureas and thioureas as bifunctional organocatalysts

  • Viera Poláčková,
  • Dominika Krištofíková,
  • Boglárka Némethová,
  • Renata Górová,
  • Mária Mečiarová and
  • Radovan Šebesta

Beilstein J. Org. Chem. 2021, 17, 2629–2641, doi:10.3762/bjoc.17.176

Graphical Abstract
  • ratio of 86:14 and high enantiomeric purity of 95:5 er for the major diastereomer (Table 1, entry 1). Using chloroform/isopropyl alcohol 9:1 as the solvent mixture afforded after 120 hours, aldehyde 10a in 45% yield with 83:17 dr and 97:3 er (Table 1, entry 2). The Michael addition in methanol catalyzed
  • by only 3 mol % (S,R)-C1 after 72 hours provided only 18% yield, but with high enantiomeric purity (99:1, Table 1, entry 5). The reaction without a base did not provide the desired product 10a (Table 1, entry 6). Moreover, a reaction performed with other acidic additives (phenylboronic acid, p
  • -toluenesulfonic acid) provided after 72 hours only 18% and 23% yield of the product with compromised diastereomeric and enantiomeric purity (Table 1, entries 3 and 4). When, we applied 3 mol % of catalyst (S,R)-C1 during 48 hours, we obtained 73% yield with diastereomeric purity 83:17 and high enantiomeric purity
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Published 25 Oct 2021

Enantioselective PCCP Brønsted acid-catalyzed aminalization of aldehydes

  • Martin Kamlar,
  • Robert Reiberger,
  • Martin Nigríni,
  • Ivana Císařová and
  • Jan Veselý

Beilstein J. Org. Chem. 2021, 17, 2433–2440, doi:10.3762/bjoc.17.160

Graphical Abstract
  • the enantioselectivity of the aminalization reaction. While most solvents tested showed to be effective at room temperature, the enantiomeric purity of the corresponding aminal 3a was low in all cases (Table 1, entries 1–5). On the other hand, the yield of 3a was satisfactory in all reactions. In
  • optimal for the enantiocontrol of the model reaction, affording the product 3a in 90% yield with an enantiomeric purity of 66% ee (Table 1, entry 7). Additionally, the effect of molecular sieves on the course of the reaction was investigated and the obtained results demonstrated that molecular sieves
  • dramatically improved the enantioselectivity (Table 1, entries 9–11). In particular, when the aminalization reaction between 1a and 2a was carried out in the presence of 5 Å molecular sieves, the corresponding product 3a was delivered in high yield (96%) and with enantiomeric purity 80% ee (Table 1, entry 11
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Published 16 Sep 2021

CF3-substituted carbocations: underexploited intermediates with great potential in modern synthetic chemistry

  • Anthony J. Fernandes,
  • Armen Panossian,
  • Bastien Michelet,
  • Agnès Martin-Mingot,
  • Frédéric R. Leroux and
  • Sébastien Thibaudeau

Beilstein J. Org. Chem. 2021, 17, 343–378, doi:10.3762/bjoc.17.32

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Published 03 Feb 2021

Recent progress in the synthesis of homotropane alkaloids adaline, euphococcinine and N-methyleuphococcinine

  • Dimas J. P. Lima,
  • Antonio E. G. Santana,
  • Michael A. Birkett and
  • Ricardo S. Porto

Beilstein J. Org. Chem. 2021, 17, 28–41, doi:10.3762/bjoc.17.4

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  • amide, confirming to be a sample with a high level of enantiomeric purity. As in Murahashi’s synthesis, Meyers also utilized a chiral auxiliary for asymmetric induction. Nonetheless, this method differed from Murahashi's by presenting a diastereoselective intramolecular Mannich cyclization to form the
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Published 05 Jan 2021

Synthesis of monophosphorylated lipid A precursors using 2-naphthylmethyl ether as a protecting group

  • Jundi Xue,
  • Ziyi Han,
  • Gen Li,
  • Khalisha A. Emmanuel,
  • Cynthia L. McManus,
  • Qiang Sui,
  • Dongmian Ge,
  • Qi Gao and
  • Li Cai

Beilstein J. Org. Chem. 2020, 16, 1955–1962, doi:10.3762/bjoc.16.162

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  • )-3-hydroxytetradecanoate (5) in 98% yield. The same hydrogenation reaction was carried out using the (S)-Ru(OAc)2(BINAP) catalyst. Then both the R and S products were compared using chiral HPLC to confirm the absolute configuration and enantiomeric purity (Figure S1, Supporting Information File 1
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Published 10 Aug 2020

Fluorinated phenylalanines: synthesis and pharmaceutical applications

  • Laila F. Awad and
  • Mohammed Salah Ayoup

Beilstein J. Org. Chem. 2020, 16, 1022–1050, doi:10.3762/bjoc.16.91

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  • product 2-[18F]FPhe 46 in 43% yield, whereas under microwave irradiation a 34% yield was obtained. Under the optimized conditions, the enantiomeric purity was reported to be ≥94% ee [46] (Scheme 10). 1.3. Photooxidative cyanation of fluorinated benzylamine A convenient, protecting group-free, and
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Published 15 May 2020

Copper-catalysed alkylation of heterocyclic acceptors with organometallic reagents

  • Yafei Guo and
  • Syuzanna R. Harutyunyan

Beilstein J. Org. Chem. 2020, 16, 1006–1021, doi:10.3762/bjoc.16.90

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  • the synthesis of the corresponding products with good yield and enantiomeric purity (up to 83% yield and 97% ee). Furthermore, a large variety of vinylalanes was investigated, and the product 2l was further derivatised into a chiral bicyclic structure (5, Scheme 2A). In addition, simple vinyl
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Published 14 May 2020

Combining enyne metathesis with long-established organic transformations: a powerful strategy for the sustainable synthesis of bioactive molecules

  • Valerian Dragutan,
  • Ileana Dragutan,
  • Albert Demonceau and
  • Lionel Delaude

Beilstein J. Org. Chem. 2020, 16, 738–755, doi:10.3762/bjoc.16.68

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  • et. al. [82]. The starting dienynes were obtained in a high enantiomeric purity starting form 2,6-dimethyl-1,4-benzoquinone and isoprene via an asymmetric Diels–Alder reaction. The domino metathesis reactions induced by the Grubbs second-generation catalyst proceeded in good yield (92%) thereby
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Published 16 Apr 2020

Synthesis of disparlure and monachalure enantiomers from 2,3-butanediacetals

  • Adam Drop,
  • Hubert Wojtasek and
  • Bożena Frąckowiak-Wojtasek

Beilstein J. Org. Chem. 2020, 16, 616–620, doi:10.3762/bjoc.16.57

Graphical Abstract
  • ), (−)-monachalure (4, (7S,8R)-cis-7,8-epoxyoctadecane) and their olefinic precursors in addition to (+)-disparlure (1) [11][12]. For the gypsy moth a high enantiomeric purity of (+)-disparlure (>98% ee) is required to evoke the male’s sexual response and even a small percentage of (−)-disparlure abolishes the
  • also been described [29]. However, many of these methods have some drawbacks – the most important one being the insufficient enantiomeric purity for biological and commercial applications [29]. (+)-Disparlure used in most commercial lures is prepared by the Sharpless epoxidation reaction, which gives
  • disparlure and monachalure with high enantiomeric purity. It can also be adapted for preparation of other chiral cis-epoxides. 2,3-Butanediacetals obtained from tartaric acid dimethyl diester contain protected hydroxy groups and two functional groups suitable for the attachment of various substituents. trans
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Published 03 Apr 2020

Synthesis and circularly polarized luminescence properties of BINOL-derived bisbenzofuro[2,3-b:3’,2’-e]pyridines (BBZFPys)

  • Ryo Takishima,
  • Yuji Nishii,
  • Tomoaki Hinoue,
  • Yoshitane Imai and
  • Masahiro Miura

Beilstein J. Org. Chem. 2020, 16, 325–336, doi:10.3762/bjoc.16.32

Graphical Abstract
  • ), 7.94 (d, J = 8.9 Hz, 2H); 13C NMR (100 MHz, CDCl3) δ 31.25, 34.61, 110.62, 117.54, 123.49, 124.01, 126.36, 129.35, 131.34, 131.42, 146.69, 152.29; HRMS–APCI (m/z): [M + H]+ calcd for C28H31O2, 399.2330; found, 399.2319. The enantiomeric purity was confirmed by HPLC analysis: CHIRAL ART Amylose-SA
  • ), 19F NMR (376 MHz, CDCl3) δ 69.06; HRMS–APCI (m/z): [M + H]+ calcd for C38H35F2N2O2, 589.2644; found, 589.2661. The enantiomeric purity was confirmed by HPLC analysis: CHIRAL ART Cellulose-SB column, n-hexane/chloroform 95:5, 1.0 mL/min, 40 °C; (S)-2: tR = 9.86 min, (R)-2: tR = 21.29 min, UV detection
  • , 121.55, 122.67, 123.15, 124.27, 125.03, 126.13, 129.10, 129.30, 130.90, 132.04, 141.35, 147.49, 149.54, 154.00, 161.86, 162.48; HRMS–APCI (m/z): [M + H]+ calcd for C50H45N2O4, 737.3367; found, 737.3374. The enantiomeric purity was confirmed by HPLC analysis: CHIRAL ART Amylose-SA column, n-hexane
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Published 06 Mar 2020
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