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Search for "high yield" in Full Text gives 593 result(s) in Beilstein Journal of Organic Chemistry. Showing first 200.

Asymmetric organocatalyzed synthesis of coumarin derivatives

  • Natália M. Moreira,
  • Lorena S. R. Martelli and
  • Arlene G. Corrêa

Beilstein J. Org. Chem. 2021, 17, 1952–1980, doi:10.3762/bjoc.17.128

Graphical Abstract
  • reported an enantioselective 1,4-addition of azadienes 71 to 3-homoacyl coumarins 70 to achieve benzofuran coumarin derivatives 72 [57]. It was possible to obtain good to excellent diastereo- and enantioselectivities by using a low amount of the catalyst, besides the high yield of the reaction. The best
  • /indandione-fused spirocyclopentanes 104 bearing four contiguous stereogenic centers, was described by Chen et al. [68]. This transformation was catalyzed by a cinchona-thiourea derivative 105 furnishing the spiro compounds with good to high yield and enantioselectivity (Scheme 33). In this method two
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Published 03 Aug 2021

Development of N-F fluorinating agents and their fluorinations: Historical perspective

  • Teruo Umemoto,
  • Yuhao Yang and
  • Gerald B. Hammond

Beilstein J. Org. Chem. 2021, 17, 1752–1813, doi:10.3762/bjoc.17.123

Graphical Abstract
  • aromatics such as phenol, cresol, and naphthalene were fluorinated in chloroform at 22 °C (Scheme 18). The N-F imide reagent 7-1a fluorinated the sodium salt of diethyl 1-methylmalonate at −10 °C to give the corresponding fluoro product in high yield (96%). Later (1991 and 1992), the same laboratory
  • ], which was an alternative to N-fluoroquinuclidinium fluoride (6-1) (Scheme 20). The triflate 8-1 was prepared in high yield by the counteranion replacement reaction developed by Umemoto and co-worker [28]. The fluorinating power of triflate 8-1 was the same as that of the fluoride 6-1, but its
  • of its corresponding sulfonimide 13-1 with 10% F2/N2 in the presence of NaF and in high yield (Scheme 28) [57]. NFOBS is a stable and crystalline solid of mp 139–140 °C (dec) with good fluorinating power. Its usefulness was demonstrated through fluorination reactions with different types of
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Published 27 Jul 2021

A recent overview on the synthesis of 1,4,5-trisubstituted 1,2,3-triazoles

  • Pezhman Shiri,
  • Ali Mohammad Amani and
  • Thomas Mayer-Gall

Beilstein J. Org. Chem. 2021, 17, 1600–1628, doi:10.3762/bjoc.17.114

Graphical Abstract
  • -triazoles. The postfunctionalization of disubstituted 1,2,3-triazole was also explained with a range of C–C- and C–N-bond-forming reactions. A number of fully substituted 1,2,3-triazoles was provided from different compounds in moderate to high yield under mild conditions. In the last years, the
  • enaminones 18 with tosyl azide. A wide range of desired 5-thiolated 1,2,3-triazoles 19 has been prepared in good to high yield in H2O as solvent using TMEDA as a weak base, thus providing an environmentally friendly procedure that was demonstrated to be practicable also on a gram scale. A wide range of β
  • fully substituted triazoles in good to high yield. The phenyl ring could also be replaced by naphthyl and furyl rings to give the corresponding products in good to excellent yield. Besides, aryl and alkyl groups for R2 displayed applicability in the preparation of corresponding 1,4,5-trisubstituted
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Published 13 Jul 2021

A straightforward conversion of 1,4-quinones into polycyclic pyrazoles via [3 + 2]-cycloaddition with fluorinated nitrile imines

  • Greta Utecht-Jarzyńska,
  • Karolina Nagła,
  • Grzegorz Mlostoń,
  • Heinz Heimgartner,
  • Marcin Palusiak and
  • Marcin Jasiński

Beilstein J. Org. Chem. 2021, 17, 1509–1517, doi:10.3762/bjoc.17.108

Graphical Abstract
  •  3). Irrespective of the electronic properties of the substituent X located at the C(4) atom of the aryl ring in the precursor 8, generally, a high yield of the isolated products 9 was observed (78–97%). Only for derivatives bearing strongly electron-withdrawing groups X (i.e., CN, NO2), a longer
  • ]-cycloadducts by air oxidation were isolated exclusively. Additionally, the X-ray structure of 9d is shown in Figure 2. Similar results were obtained starting with 1,4-anthraquinone (1b) and selected hydrazonoyl bromides 8. In this series, fused pyrazoles 9i–l were obtained in high yield (63–92%, Scheme 3
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Published 28 Jun 2021

Co-crystallization of an organic solid and a tetraaryladamantane at room temperature

  • Fabian Rami,
  • Jan Nowak,
  • Felix Krupp,
  • Wolfgang Frey and
  • Clemens Richert

Beilstein J. Org. Chem. 2021, 17, 1476–1480, doi:10.3762/bjoc.17.103

Graphical Abstract
  • wide range of chemically interesting molecular entities, further favoring it as test substance. Two molecular hosts were to be employed, namely TDA and TEO (Figure 1), both of which are readily synthesized in high yield [14][15]. Exploratory experiments were performed aiming at crystallizing at
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Published 21 Jun 2021

Icilio Guareschi and his amazing “1897 reaction”

  • Gian Cesare Tron,
  • Alberto Minassi,
  • Giovanni Sorba,
  • Mara Fausone and
  • Giovanni Appendino

Beilstein J. Org. Chem. 2021, 17, 1335–1351, doi:10.3762/bjoc.17.93

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  • posthumously in 1919 [35]. In 1894, Guareschi reported the first high-yield synthesis and the structure elucidation of triacetonamine (6, Scheme 3) [35][36][37], the sterically hindered amine that is the starting material for the synthesis of the popular oxidant TEMPO [38]. Triacetonamine had first been
  • reported in 1874 and was synthesized by refluxing of a saturated solution of ammonia in acetone, but the structure of this trimer had not yet been established [39]. Guareschi obtained triacetonamine in high yield (>70%) by treatment of phorone (7), the trimer of acetone, with ammonia and established the
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Published 25 May 2021

A comprehensive review of flow chemistry techniques tailored to the flavours and fragrances industries

  • Guido Gambacorta,
  • James S. Sharley and
  • Ian R. Baxendale

Beilstein J. Org. Chem. 2021, 17, 1181–1312, doi:10.3762/bjoc.17.90

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Published 18 May 2021

N-tert-Butanesulfinyl imines in the asymmetric synthesis of nitrogen-containing heterocycles

  • Joseane A. Mendes,
  • Paulo R. R. Costa,
  • Miguel Yus,
  • Francisco Foubelo and
  • Camilla D. Buarque

Beilstein J. Org. Chem. 2021, 17, 1096–1140, doi:10.3762/bjoc.17.86

Graphical Abstract
  • in the synthesis of (–)-batzelladine D 61 and (–)-13-epi-batzelladine D 62. The reaction of (SS)-58 with methyl bromoacetate in the presence on Zn and CuCl in THF, left, after removal of the sulfinyl group under acidic conditions, to β-amino ester ammonium chloride 59 in high yield. This compound was
  • rhodium catalyst in dioxane, in the presence of 2 equivalents of MeOH, at 65 °C, leading to compounds 65 with high diastereomeric ratio. Crude amides 65 were converted into the corresponding pyrrolidines 66 in high yield by stirring at room temperature for 1 h in presence of 2.0 equivalents of LiHMDS
  • -amino ketone derivative 124 in high yield and diastereoselectivity (Scheme 34). A reduction of 124 gave a mixture of diastereomeric alcohols, and the one with (R)-configuration at the benzylic position was isolated in 54% yield. Further treatment of the alcohol with NaH furnished a cyclized product
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Published 12 May 2021

Nitroalkene reduction in deep eutectic solvents promoted by BH3NH3

  • Chiara Faverio,
  • Monica Fiorenza Boselli,
  • Patricia Camarero Gonzalez,
  • Alessandra Puglisi and
  • Maurizio Benaglia

Beilstein J. Org. Chem. 2021, 17, 1041–1047, doi:10.3762/bjoc.17.83

Graphical Abstract
  • eutectic mixtures DES D and E, and a ChCl/ʟ-(+)-lactic acid mixture, DES F (Table 2). The reduction worked in all systems, in low yield with DES E (where it was not possible to separate the product from the DES) and DES F, but it proceeded in very high yield and short reaction time in DES D. Based on these
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Published 06 May 2021

Synthetic accesses to biguanide compounds

  • Oleksandr Grytsai,
  • Cyril Ronco and
  • Rachid Benhida

Beilstein J. Org. Chem. 2021, 17, 1001–1040, doi:10.3762/bjoc.17.82

Graphical Abstract
  • guanidine to a carbodiimide was reported by Richter and Ulrich in 1981 (Scheme 38) [78]. The authors prepared an N1,N2,N3,N4,N5-pentaarylbiguanide derivative by reacting an N,N’,N’’-triarylguanidine with diphenylcarbodiimide. The reaction occurred at room temperature in dichloromethane with a high yield
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Published 05 May 2021

Metal-free glycosylation with glycosyl fluorides in liquid SO2

  • Krista Gulbe,
  • Jevgeņija Lugiņina,
  • Edijs Jansons,
  • Artis Kinens and
  • Māris Turks

Beilstein J. Org. Chem. 2021, 17, 964–976, doi:10.3762/bjoc.17.78

Graphical Abstract
  • mannosyl fluoride α-1a was achieved and the desired O-mannoside 3a was isolated in a high yield and α-selectivity. Hemiacetal α-4 was isolated as the only side-product formed via glycosyl donor hydrolysis with the water present in commercial SO2 [62]. To note, at lower temperatures (Table 1, entry 1) no
  • were not fully consumed. The superior reactivity of glycosyl fluoride α-1a in liquid SO2 compared to other halides was clearly demonstrated when thiol 2c was used as an acceptor (Table 3, entries 4–6). S-Mannoside 3c was isolated from mannosyl fluoride α-1a in twice as high yield as from the
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Published 29 Apr 2021

Prins cyclization-mediated stereoselective synthesis of tetrahydropyrans and dihydropyrans: an inspection of twenty years

  • Asha Budakoti,
  • Pradip Kumar Mondal,
  • Prachi Verma and
  • Jagadish Khamrai

Beilstein J. Org. Chem. 2021, 17, 932–963, doi:10.3762/bjoc.17.77

Graphical Abstract
  • allylic geminal bissilyl alcohol 221 for the construction of THP ring A of (−)-exiguolide via Prins cyclization with an aldehyde in the presence of Lewis acid as a promoter [95]. High yield and excellent diastereoselectivity were obtained under standard silyl-Prins cyclization conditions using TMSOTf as
  • the stereoselective construction of the THF ring (Scheme 67) [109]. A series of geminal bishalogen-containing fused THPs was synthesized in high yield (up to 80%) and excellent diastereoselectivity. A Prins cyclization mechanism was proposed for the above transformation in the presence of TiCl4
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Published 29 Apr 2021

Synthetic reactions driven by electron-donor–acceptor (EDA) complexes

  • Zhonglie Yang,
  • Yutong Liu,
  • Kun Cao,
  • Xiaobin Zhang,
  • Hezhong Jiang and
  • Jiahong Li

Beilstein J. Org. Chem. 2021, 17, 771–799, doi:10.3762/bjoc.17.67

Graphical Abstract
  • irradiation (Scheme 61). It was worth mentioning that longer reaction times and increased DIPEA loading were required owing to the inactivity of α-bromoketones, esters, and nonactivated sulfones; however, corresponding products could be given in high yield. When the DIPEA molarity was double that of
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Published 06 Apr 2021

Synthesis of dibenzosuberenone-based novel polycyclic π-conjugated dihydropyridazines, pyridazines and pyrroles

  • Ramazan Koçak and
  • Arif Daştan

Beilstein J. Org. Chem. 2021, 17, 719–729, doi:10.3762/bjoc.17.61

Graphical Abstract
  • dihydropyridazine 3e, the intended pyridazine compound could not be obtained. Alternatively, nitrogen monoxide (NO) gas was used as oxidizer and pyridazineamide 4e was obtained in high yield (83%, Scheme 5). In another important part of this study, pyridazines were converted into the corresponding pyrroles via a
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Published 15 Mar 2021

α,γ-Dioxygenated amides via tandem Brook rearrangement/radical oxygenation reactions and their application to syntheses of γ-lactams

  • Mikhail K. Klychnikov,
  • Radek Pohl,
  • Ivana Císařová and
  • Ullrich Jahn

Beilstein J. Org. Chem. 2021, 17, 688–704, doi:10.3762/bjoc.17.58

Graphical Abstract
  • the convex face of the bicyclic system. Amide 9p with an enantiomerically enriched cyclohex-2-enyl substituent cyclized with exclusive diastereoselectivity and only two diastereomers 12pA differing in the orientation of the hydroxy group were obtained in high yield. The radical coupling with TEMPO
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Published 09 Mar 2021

[2 + 1] Cycloaddition reactions of fullerene C60 based on diazo compounds

  • Yuliya N. Biglova

Beilstein J. Org. Chem. 2021, 17, 630–670, doi:10.3762/bjoc.17.55

Graphical Abstract
  • involved in C60 reactions with diazo compounds is much wider. In addition, the high yield of the target products and the nearly unlimited variability of substituents in the cyclopropane moiety should be noted as advantages of the latter method. Nevertheless, a drawback that all the [2 + 1] cycloaddition
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Published 05 Mar 2021

Synthetic strategies of phosphonodepsipeptides

  • Jiaxi Xu

Beilstein J. Org. Chem. 2021, 17, 461–484, doi:10.3762/bjoc.17.41

Graphical Abstract
  • -hydroxyglutarate (84) in a Mitsunobu reaction to generate the γ-phosphonodepsipeptide 79 in a high yield of 66% (Scheme 27) [28]. Synthesis of phosphonodepsipeptides via the multicomponent condensation of amides, aldehydes, and phosphites followed by alcoholysis with hydroxy esters Previously, the Mannich-type
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Published 16 Feb 2021

Helicene synthesis by Brønsted acid-catalyzed cycloaromatization in HFIP [(CF3)2CHOH]

  • Takeshi Fujita,
  • Noriaki Shoji,
  • Nao Yoshikawa and
  • Junji Ichikawa

Beilstein J. Org. Chem. 2021, 17, 396–403, doi:10.3762/bjoc.17.35

Graphical Abstract
  • % yield. Similarly, C-shaped double helical helicene 5b was obtained in high yield using m-dibromobenzene 6b with two acetal moieties, prepared from m-xylene (Scheme 5b). We also achieved the synthesis of heterohelicenes, which involve heteroatoms in the helicene frameworks, via a Suzuki–Miyaura coupling
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Published 09 Feb 2021

Coupling biocatalysis with high-energy flow reactions for the synthesis of carbamates and β-amino acid derivatives

  • Alexander Leslie,
  • Thomas S. Moody,
  • Megan Smyth,
  • Scott Wharry and
  • Marcus Baumann

Beilstein J. Org. Chem. 2021, 17, 379–384, doi:10.3762/bjoc.17.33

Graphical Abstract
  • resulting telescoped flow process was effectively applied across a series of acid substrates rendering the desired carbamate structures in high yield and purity. The derivatization of these products via complementary flow-based Michael addition reactions furthermore demonstrated the creation of β-amino acid
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Published 04 Feb 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

Graphical Abstract
  • compounds 161 in high yield (Scheme 40, top). The reaction of CF3-substituted 1,3-diketones 165a–d in TfOH was also deeply investigated by Klumpp et al. [101]. The syn-indanes 166a–d could cleanly be generated after successive well-defined arylation reactions via 167 (Scheme 40, bottom). Moreover, the CF3
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Published 03 Feb 2021

Regioselective chemoenzymatic syntheses of ferulate conjugates as chromogenic substrates for feruloyl esterases

  • Olga Gherbovet,
  • Fernando Ferreira,
  • Apolline Clément,
  • Mélanie Ragon,
  • Julien Durand,
  • Sophie Bozonnet,
  • Michael J. O'Donohue and
  • Régis Fauré

Beilstein J. Org. Chem. 2021, 17, 325–333, doi:10.3762/bjoc.17.30

Graphical Abstract
  • in a high yield of 94%. Accordingly, the synthesis of the chromogenic ferulate 12 was achieved in 32% overall yield in 3 steps from commercial reactants (convergent synthesis using a slight excess of the synthesized vinyl ferulate 2) and without the requirement to perform a final deprotection. As
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Published 01 Feb 2021

Diels–Alder reaction of β-fluoro-β-nitrostyrenes with cyclic dienes

  • Savva A. Ponomarev,
  • Roman V. Larkovich,
  • Alexander S. Aldoshin,
  • Andrey A. Tabolin,
  • Sema L. Ioffe,
  • Jonathan Groß,
  • Till Opatz and
  • Valentine G. Nenajdenko

Beilstein J. Org. Chem. 2021, 17, 283–292, doi:10.3762/bjoc.17.27

Graphical Abstract
  • straightforward way to novel fluorinated norbornadienes from β-fluoro-β-nitrostyrenes and CPD. Conclusion In summary, the Diels–Alder reaction of β-fluoro-β-nitrostyrenes with cyclic 1,3-dienes was investigated. A series of novel monofluorinated norbornenes was prepared in high yield up to 97%. A number of novel
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Published 27 Jan 2021

Annulation of a 1,3-dithiole ring to a sterically hindered o-quinone core. Novel ditopic redox-active ligands

  • Sergey V. Norkov,
  • Anton V. Cherkasov,
  • Andrey S. Shavyrin,
  • Maxim V. Arsenyev,
  • Viacheslav A. Kuropatov and
  • Vladimir K. Cherkasov

Beilstein J. Org. Chem. 2021, 17, 273–282, doi:10.3762/bjoc.17.26

Graphical Abstract
  • -2-thione species 6a in a high yield (Scheme 1, route 2). The red color of the reaction mixture belonging to the parent o-quinone rapidly turns into a brown color of o-quinone 6a. o-Quinone 6a was isolated as red-brown crystals by cooling the acetone/ether mixture. It is a structural analogue of o
  • manner to give the corresponding 1,3-dithiole derivatives in a high yield. On the other hand, the fact that treatment of 4 with NaH(hfac) and CS2 does not result in substitution of chlorine atoms at the quinone backbone indicates that under such conditions the gem-dithiolate species is not formed
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Published 27 Jan 2021

The preparation and properties of 1,1-difluorocyclopropane derivatives

  • Kymbat S. Adekenova,
  • Peter B. Wyatt and
  • Sergazy M. Adekenov

Beilstein J. Org. Chem. 2021, 17, 245–272, doi:10.3762/bjoc.17.25

Graphical Abstract
  • )-monoacetate (S)-80, respectively (Scheme 32). As for the transesterification, a high yield (96.5%) and enantioselectivity (91.3% ee) were obtained using lipase PS in benzene. In the case of the deacetylation, the use of Amano PS lipase in acetone gave a high yield (86.2%), enantioselectivity (91.7% ee), and
  • alkenes with the CF3SiMe3–NaI system has been studied (Table 2). Difluorocarbene addition to α-fluorostyrenes enabled the efficient synthesis of trifluorocyclopropanes 34 [41]. The difluorocyclopropanation of protected cyclohexenone yielded cyclopropane 35 [42]. Difluorocyclopropane 36 was formed in high
  • yield from the α-bromopyridine-substituted N-Boc-3,4-dehydropiperidine. When the same reaction was attempted on the bromine-free analog, the yield was only 22% [43]. The difluorocyclopropanation of an alkenyl trifluoroborate using the TMSCF3–NaI system afforded the boronate derivative 37 [44]. The
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Published 26 Jan 2021

Selective synthesis of α-organylthio esters and α-organylthio ketones from β-keto esters and sodium S-organyl sulfurothioates under basic conditions

  • Jean C. Kazmierczak,
  • Roberta Cargnelutti,
  • Thiago Barcellos,
  • Claudio C. Silveira and
  • Ricardo F. Schumacher

Beilstein J. Org. Chem. 2021, 17, 234–244, doi:10.3762/bjoc.17.24

Graphical Abstract
  • conditions to obtain ethyl 2-(benzylthio)acetate (3a) selectively and in a high yield in hand (Table 1, entry 22), we turned our attention to find an ideal protocol to synthesize 4a. When 0.5 mmol of 1a and 1 mmol of 2a were used in the presence of 2 equivalents of NaOH under air, compound 4a was obtained in
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Published 26 Jan 2021
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