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Search for "cinchona" in Full Text gives 64 result(s) in Beilstein Journal of Organic Chemistry.

A novel recyclable organocatalyst for the gram-scale enantioselective synthesis of (S)-baclofen

  • Gyula Dargó,
  • Dóra Erdélyi,
  • Balázs Molnár,
  • Péter Kisszékelyi,
  • Zsófia Garádi and
  • József Kupai

Beilstein J. Org. Chem. 2023, 19, 1811–1824, doi:10.3762/bjoc.19.133

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  • , application, and recycling of a new lipophilic cinchona squaramide organocatalyst. The synthesized lipophilic organocatalyst was applied in Michael additions. The catalyst was utilized to promote the Michael addition of cyclohexyl Meldrum’s acid to 4-chloro-trans-β-nitrostyrene (quantitative yield, up to 96
  • , acetonitrile, with 91–100% efficiency, and the catalyst was reused in five reaction cycles without the loss of activity and selectivity. Keywords: baclofen; catalyst recovery; lipophilic cinchona squaramide; organocatalysis; stereoselective catalysis; Introduction In today’s chemical industry, catalytic
  • recycling of the organocatalysts can be achieved in a simple step by centrifugation or filtration. Previously, we have demonstrated the homogeneous and heterogeneous recycling of cinchona-based organocatalysts [20][25][26][29]. Continuing our work, we aimed to synthesize a novel, recyclable lipophilic
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Published 24 Nov 2023

N-Sulfenylsuccinimide/phthalimide: an alternative sulfenylating reagent in organic transformations

  • Fatemeh Doraghi,
  • Seyedeh Pegah Aledavoud,
  • Mehdi Ghanbarlou,
  • Bagher Larijani and
  • Mohammad Mahdavi

Beilstein J. Org. Chem. 2023, 19, 1471–1502, doi:10.3762/bjoc.19.106

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  • thiiranium ion by the tosylamide and deprotonation led to the final product 99 or 100 (Scheme 41). Through the coupling reaction of N-(aryl/alkylthio)succinimides 1 with 5H-oxazol-4-ones 101 in the presence of an organocatalyst named cinchona alkaloid-derived squaramide F, a series of α-sulfenylated products
  • acid catalyst I, leading to the formation of an electrophilic sulfenium source (Scheme 49). The use of dimeric cinchona alkaloid J as another organocatalyst for α-sulfenylation of deconjugated butyrolactam substrates 117 with N-(arylsulfanyl)succinimides 1 demonstrated in Mukherjee′s work (Scheme 50
  • reacted with N-(arylthio)succinimide 1 or N-(arylthio)phthalimide 14 as the sulfenylating reagents in the presence of cinchona-derived thiourea O as a catalyst to afford the corresponding chiral naphthalenone products 126 under mild reaction conditions. Another work from Anbarasan and Chaitanya on the use
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Published 27 Sep 2023

Selective construction of dispiro[indoline-3,2'-quinoline-3',3''-indoline] and dispiro[indoline-3,2'-pyrrole-3',3''-indoline] via three-component reaction

  • Ziying Xiao,
  • Fengshun Xu,
  • Jing Sun and
  • Chao-Guo Yan

Beilstein J. Org. Chem. 2023, 19, 1234–1242, doi:10.3762/bjoc.19.91

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  • multicomponent reactions have been successfully developed to construct multifunctionalized or polycyclic spirooxindoles. For example, Zhang successfully developed a recyclable bifunctional cinchona/thiourea-catalyzed four-component Michael/Mannich cyclization sequence for the asymmetric synthesis of
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Published 22 Aug 2023
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  • . Cinchona alkaloid O2 was the efficient catalyst for this asymmetric C–C bond formation delivering the products with moderate to good enantioselectivities. One example was documented involving β-naphthol as nucleophile and another example included electron-rich phenol (Scheme 31) [61]. Lin, Duan and co
  • benzothiazolimines. Thiourea-catalyzed reaction between β-naphthol and isatin-derived ketamine. Quinine-derived molecule as catalyst. Cinchona alkaloid as catalyst. aza-Friedel–Crafts reaction by phase transfer catalyst. Disulfonamide-catalyzed reaction. Heterogenous thiourea-catalyzed aza-Friedel–Crafts reaction
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Published 28 Jun 2023

Facile access to 3-sulfonylquinolines via Knoevenagel condensation/aza-Wittig reaction cascade involving ortho-azidobenzaldehydes and β-ketosulfonamides and sulfones

  • Ksenia Malkova,
  • Andrey Bubyrev,
  • Stanislav Kalinin and
  • Dmitry Dar’in

Beilstein J. Org. Chem. 2023, 19, 800–807, doi:10.3762/bjoc.19.60

Graphical Abstract
  • occurrence among natural products [1] and is a key structural component of several pharmaceuticals, agrochemicals, dyestuffs, and materials. Particularly, the well-known antimalarial alkaloid quinine isolated from Cinchona bark comprises a quinoline core (Figure 1a) [2]. Moreover, numerous quinoline
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Published 09 Jun 2023

Menadione: a platform and a target to valuable compounds synthesis

  • Acácio S. de Souza,
  • Ruan Carlos B. Ribeiro,
  • Dora C. S. Costa,
  • Fernanda P. Pauli,
  • David R. Pinho,
  • Matheus G. de Moraes,
  • Fernando de C. da Silva,
  • Luana da S. M. Forezi and
  • Vitor F. Ferreira

Beilstein J. Org. Chem. 2022, 18, 381–419, doi:10.3762/bjoc.18.43

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  • from cinchonine PTC 44 as catalyst. Despite of good yields, the method did not demonstrate good enantioselectivity results [104]. Berkessel and co-workers, in turn, described the use of asymmetric Weitz–Scheffer-type epoxidation of menadione (10), mediated by cinchona alkaloid PTC 45, showing high
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Published 11 Apr 2022

New advances in asymmetric organocatalysis

  • Radovan Šebesta

Beilstein J. Org. Chem. 2022, 18, 240–242, doi:10.3762/bjoc.18.28

Graphical Abstract
  • catalyzed by cinchona-based thiourea catalysts [27]. As guest editor of this thematic issue, I am grateful to all authors for their excellent contributions. I thank the referees for providing their expertise and time, and the whole team at the Beilstein Journal of Organic Chemistry for their great level of
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Published 28 Feb 2022

Organocatalytic asymmetric nitroso aldol reaction of α-substituted malonamates

  • Ekta Gupta,
  • Narendra Kumar Vaishanv,
  • Sandeep Kumar,
  • Raja Krishnan Purshottam,
  • Ruchir Kant and
  • Kishor Mohanan

Beilstein J. Org. Chem. 2022, 18, 217–224, doi:10.3762/bjoc.18.25

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  • metal-catalyzed reactions [31][32][33][34][35][36]. The most successful among them are the ʟ-proline-catalyzed reactions of enolizable aldehydes with nitrosoarenes [37][38][39][40][41][42][43]. Besides ʟ-proline and its derivatives, various secondary amines derived from BINOL and cinchona alkaloids were
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Published 21 Feb 2022

Bifunctional thiourea-catalyzed asymmetric [3 + 2] annulation reactions of 2-isothiocyanato-1-indanones with barbiturate-based olefins

  • Jiang-Song Zhai and
  • Da-Ming Du

Beilstein J. Org. Chem. 2022, 18, 25–36, doi:10.3762/bjoc.18.3

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  • results, it was found that the yield of product did not increase significantly with the cinchona alkaloid-derived squaramide catalysts (Table 1, entries 2 and 3). Consequently, we decided to explore the effects of different types of catalysts on the reaction. Through experiments, it can be found that
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Published 04 Jan 2022

Recent advances in organocatalytic asymmetric aza-Michael reactions of amines and amides

  • Pratibha Sharma,
  • Raakhi Gupta and
  • Raj K. Bansal

Beilstein J. Org. Chem. 2021, 17, 2585–2610, doi:10.3762/bjoc.17.173

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  • asymmetric aza-MR. Thus, the review includes the examples wherein cinchona alkaloids, squaramides, chiral amines, phase-transfer catalysts and chiral bifunctional thioureas have been used, which activate the substrates through hydrogen bond formation. Most of these reactions are accompanied by high yields
  • compounds; however, in order to comply with the requirements of a mini review, additions of amines and amides only will be included. 1. Non-covalent bonding organocatalytic aza-Michael reactions Organocatalysts catalyzing aza-MRs through mainly hydrogen bonding include cinchona alkaloids, squaramide
  • derivatives, phase-transfer catalysts and bifunctional thiourea derivatives. 1.1 Reactions catalyzed by chiral cinchona alkaloid derivatives Cai et al. prepared and used a number of organocatalysts from Cinchona alkaloids for the aza-MR of aniline (1) with chalcone (2) to obtain the adducts 4 in poor to very
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Published 18 Oct 2021

Base-free enantioselective SN2 alkylation of 2-oxindoles via bifunctional phase-transfer catalysis

  • Mili Litvajova,
  • Emiliano Sorrentino,
  • Brendan Twamley and
  • Stephen J. Connon

Beilstein J. Org. Chem. 2021, 17, 2287–2294, doi:10.3762/bjoc.17.146

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  • synthesis of a potent CRTH2 receptor antagonist. Keywords: alkylation; base-free; cinchona alkaloids; CRTH2 antagonist; hydrogen-bonding; oxindole; phase-transfer catalysis; Introduction The 2-oxindole scaffold is an important motif present in a myriad of natural products. Among 2-oxidole derivatives, 3,3
  • investigation by evaluating, as a model alkylation, the phase-transfer-catalysed benzylation of substrate 5 under ‘classical’ basic reaction conditions using cinchona alkaloid-based catalysts capable of hydrogen-bonding as a control element [33][34][35][36][37][38][39][40]. As expected, the ester group α to the
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Published 02 Sep 2021

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
  • ammonium salts derived from cinchona alkaloids [28]. Therefore, the asymmetric synthesis of coumarin derivatives is herein presented according to the activation mode, i.e., via covalent or non-covalent bonding. Furthermore, the use of bifunctional catalysts and multicatalysis are discussed as well
  • enantioselective Michael addition of ketones 20 to 3-aroylcoumarins 19 [38]. For this transformation, the authors used a cinchona alkaloid-derived primary amine catalyst 22 (Scheme 6a). The study was performed with cyclic and acyclic ketones 20 and various 3-aroylcoumarins 19 and the desired products 21 were
  • stereoselective one-pot procedure for the synthesis of five-membered annulated coumarins 28 was described by the group of Enders [40]. Using dual catalysis, with a cinchona primary amine derivative 22 and silver carbonate, a series of functionalized coumarin derivatives 28 were obtained in good yields (up to 91
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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

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  • (entry 6, Figure 9), it was less than that obtained (74% ee) by N-fluorosultam (R)-27-6 with the same substrate (see the previous section 1-27). 1-29. N-Fluorinated cinchona alkaloid derivatives by combination with Selectfluor In 2000, Shibata and Takeuchi reported a far more practical enantioselective
  • fluorination method. They discovered that the fluorination of carbanions with Selectfluor occurred in a highly enantioselective manner when carried out in the presence of cinchona alkaloid derivatives [95]. This method consisted of two simple steps. Firstly, the cinchona alkaloid is reacted with Selectfluor in
  • reported by Banks when quinuclidine was N-fluorinated with Selectfluor [62] (Scheme 67). Subsequently, in 2001, Shibata et al. presented full details of their studies including the definitive identification of N-fluorinated cinchona alkaloids by X-ray crystallography analysis and further applications [96
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Published 27 Jul 2021
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  • Deniz Tozendemir Cihangir Tanyeli Department of Chemistry, Middle East Technical University, 06800 Ankara, Turkey 10.3762/bjoc.17.43 Abstract Cinchona alkaloid-derived organocatalysts are widely employed in various asymmetric transformations, yielding products with high enantiopurity. In this
  • %) catalyst loading. Selected enantiomerically enriched sulfa-Michael addition products were subjected to oxidation to obtain the corresponding sulfones. Keywords: asymmetric synthesis; bifunctional catalysis; cinchona alkaloids; organocatalysis; sulfa-Michael reaction; Introduction Derivatives of the
  • naturally occurring cinchona alkaloids have shown remarkable performance as organocatalysts for stereoselective synthesis in the past decade [1][2][3][4][5][6]. Among them, quinine-derived organocatalysts make a noteworthy appearance in the formation of new stereogenic centres, which can serve as valuable
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Published 18 Feb 2021

Controlling the stereochemistry in 2-oxo-aldehyde-derived Ugi adducts through the cinchona alkaloid-promoted electrophilic fluorination

  • Yuqing Wang,
  • Gaigai Wang,
  • Anatoly A. Peshkov,
  • Ruwei Yao,
  • Muhammad Hasan,
  • Manzoor Zaman,
  • Chao Liu,
  • Stepan Kashtanov,
  • Olga P. Pereshivko and
  • Vsevolod A. Peshkov

Beilstein J. Org. Chem. 2020, 16, 1963–1973, doi:10.3762/bjoc.16.163

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  • center. This in turn led to their increased nucleophilicity as compared to the standard Ugi adducts. As such, the stereocenter at the peptidyl position could be installed and stereodefined through the reaction with a suitable electrophile. Towards this end, we were able to deploy an asymmetric cinchona
  • alkaloid-promoted electrophilic fluorination producing enantioenriched post-Ugi adducts fluorinated at the peptidyl position. Keywords: cinchona alkaloids; electrophilic fluorination; enantioselective synthesis; 2-oxo-aldehydes; Ugi reaction; Introduction Multicomponent reactions (MCRs) [1][2][3][4][5][6
  • carbonyl compounds promoted by cinchona alkaloid derivatives developed independently by Shibata, Takeuchi and co-workers [65][66] and by the group of Cahard [67][68][69][70]. The method proved to be applicable to a broad range of substrates under a variety of conditions [71][72][73][74][75][76][77][78] and
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Published 11 Aug 2020

NHC-catalyzed enantioselective synthesis of β-trifluoromethyl-β-hydroxyamides

  • Alyn T. Davies,
  • Mark D. Greenhalgh,
  • Alexandra M. Z. Slawin and
  • Andrew D. Smith

Beilstein J. Org. Chem. 2020, 16, 1572–1578, doi:10.3762/bjoc.16.129

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  • stereogenic trifluoromethyl centers is through enantioselective addition of enolates or their equivalents to prochiral trifluoromethyl ketones (Figure 1A). Within this area, a common catalytic approach has utilized aliphatic ketones as enolate equivalents using prolinamide, cinchona, or hybrid catalysts that
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Published 30 Jun 2020

New α- and β-cyclodextrin derivatives with cinchona alkaloids used in asymmetric organocatalytic reactions

  • Iveta Chena Tichá,
  • Simona Hybelbauerová and
  • Jindřich Jindřich

Beilstein J. Org. Chem. 2019, 15, 830–839, doi:10.3762/bjoc.15.80

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  • recycle catalysts. However, only a limited number of organocatalytic moieties and functional groups have been attached to CD scaffolds so far. Cinchona alkaloids are commonly used to catalyze a wide range of enantioselective reactions. Thus, in this study, we report the preparation of new α- and β-CD
  • derivatives monosubstituted with cinchona alkaloids (cinchonine, cinchonidine, quinine and quinidine) on the primary rim through a CuAAC click reaction. Subsequently, permethylated analogs of these cinchona alkaloid–CD derivatives also were synthesized and the catalytic activity of all derivatives was
  • ) the cinchona alkaloid moiety can be successfully attached to CD scaffolds through a CuAAC reaction, (ii) the permethylated cinchona alkaloid–CD catalysts showed better results than the non-methylated CDs analogues in the AAA reaction, (iii) promising enantiomeric excesses are achieved, and (iv) the
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Published 01 Apr 2019

A novel and practical asymmetric synthesis of eptazocine hydrobromide

  • Ruipeng Li,
  • Zhenren Liu,
  • Liang Chen,
  • Jing Pan,
  • Kuaile Lin and
  • Weicheng Zhou

Beilstein J. Org. Chem. 2018, 14, 2340–2347, doi:10.3762/bjoc.14.209

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  • and methallyl iodide [10]. However, these methods were undermined by expensive reagents, poor yields, harsh reaction conditions, or complex synthetic procedures. Phase-transfer asymmetric catalysis using cinchona alkaloid-derived quaternary ammonium salts is a practical method in organic synthesis [11
  • ][12][13]. In our prior publication [14], this method was selected as the technology for the development of a process to prepare (R)-(+)-1-(5’-bromopentyl)-1-methyl-7-methoxy-2-tetralone, a key intermediate of dezocine, and N-(p-trifluoromethylbenzyl)cinchonidinium bromide (3) among 17 cinchona
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Published 06 Sep 2018

Enantioselective phase-transfer catalyzed alkylation of 1-methyl-7-methoxy-2-tetralone: an effective route to dezocine

  • Ruipeng Li,
  • Zhenren Liu,
  • Liang Chen,
  • Jing Pan and
  • Weicheng Zhou

Beilstein J. Org. Chem. 2018, 14, 1421–1427, doi:10.3762/bjoc.14.119

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  • 10.3762/bjoc.14.119 Abstract In order to prepare asymmetrically (R)-(+)-1-(5-bromopentyl)-1-methyl-7-methoxy-2-tetralone (3a), a key intermediate of dezocine, 17 cinchona alkaloid-derived catalysts were prepared and screened for the enantioselective alkylation of 1-methyl-7-methoxy-2-tetralone with 1,5
  • separated by two times of resolution with L-tartaric acid and D-tartaric acid (Scheme 1). Phase-transfer asymmetric catalysis with cinchona alkaloid-derived quaternary ammonium compounds has become one of the topics in stereoselective synthesis in both industry and academia [6][7][8][9]. It was reported [10
  • . (Some reports on the non-stereoselective alkylation of 2 were given in references [11][12]). In this paper, several cinchona-derived phase-transfer catalysts were screened for this reaction, and the structure–activity relationship for the catalysis was studied. In addition, optimizations had been made
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Published 11 Jun 2018

Recent applications of chiral calixarenes in asymmetric catalysis

  • Mustafa Durmaz,
  • Erkan Halay and
  • Selahattin Bozkurt

Beilstein J. Org. Chem. 2018, 14, 1389–1412, doi:10.3762/bjoc.14.117

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  • catalytic amounts of chiral phase-transfer agents [32][33][34]. Although the literature contains examples of calixarene derivatives used as phase-transfer catalysts (PTCs) [35], the first asymmetric quaternary ammonium salts derived from cinchona alkaloids based on the calixarene skeleton were prepared by
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Published 08 Jun 2018

Synthesis of chiral 3-substituted 3-amino-2-oxindoles through enantioselective catalytic nucleophilic additions to isatin imines

  • Hélène Pellissier

Beilstein J. Org. Chem. 2018, 14, 1349–1369, doi:10.3762/bjoc.14.114

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  • ]. An extensively used two-component variant of this reaction consists in using a preformed imine. Among chiral metal complexes, a wide variety of organocatalysts [26][27][28][29][30][31][32][33][34] has been used to promote asymmetric Mannich reactions. Among them, cinchona alkaloid 1 was employed in
  • -dicarbonyl compounds 5 performed in the presence of chiral cinchona alkaloid-derived squaramide 6 [36]. A range of chiral 3-amino-2-oxindoles 7 was obtained under mild reaction conditions in high to quantitative yields (78–99%) and uniformly excellent enantioselectivities (90–99% ee) as shown in Scheme 2. In
  • diastereoselectivity of 90% de was achieved in the reaction of 1-benzoylacetone (R2 = Me, R3 = Ph) which afforded the corresponding single diastereoisomeric product in 96% yield and 95% ee. In 2018, Tanyeli et al. reinvestigated this type of reactions in the presence of related cinchona alkaloid-derived squaramide
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Published 06 Jun 2018

A survey of chiral hypervalent iodine reagents in asymmetric synthesis

  • Soumen Ghosh,
  • Suman Pradhan and
  • Indranil Chatterjee

Beilstein J. Org. Chem. 2018, 14, 1244–1262, doi:10.3762/bjoc.14.107

Graphical Abstract
  • catalyzed by a phase-transfer catalyst [74]. Their previous findings on the same reaction using a Cinchona-based phase-transfer catalyst [75] was further improved by using Maruoka’s binaphthyl-derived ammonium salt 110. The formation of intermediate 112 (chiral catalyst still attached to the substrate) from
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Published 30 May 2018

Investigations towards the stereoselective organocatalyzed Michael addition of dimethyl malonate to a racemic nitroalkene: possible route to the 4-methylpregabalin core structure

  • Denisa Vargová,
  • Rastislav Baran and
  • Radovan Šebesta

Beilstein J. Org. Chem. 2018, 14, 553–559, doi:10.3762/bjoc.14.42

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  • afford diastereoisomeric catalysts (Sa,R,R)-C8, and (Sa,S,S)-C8, respectively. In the Michael addition of dimethyl malonate to the racemic nitroalkene 6, the cinchona-based catalysts C1–C3 performed poorly and provided the desired Michael adduct 7 in less than 10% yields (Table 1, entries 1–3). The lower
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Published 05 Mar 2018

Novel amide-functionalized chloramphenicol base bifunctional organocatalysts for enantioselective alcoholysis of meso-cyclic anhydrides

  • Lingjun Xu,
  • Shuwen Han,
  • Linjie Yan,
  • Haifeng Wang,
  • Haihui Peng and
  • Fener Chen

Beilstein J. Org. Chem. 2018, 14, 309–317, doi:10.3762/bjoc.14.19

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  • stereocontrol in alcoholytic catalytic asymmetric desymmetrizations of meso-cyclic anhydrides is of special interest [1][2][3][4][5][6][7]. Major families originating from natural products include cinchona alkaloids [8][9][10][11][12][13][14][15][16][17] and proteinogenic α-amino acids such as proline [18][19
  • -derived bifunctional derivatives catalyzed asymmetric alcoholysis of anhydride, the exploration of new effective and easily accessible fully synthetic organocatalysts through further modification of this privilege motif are always needed. Our present design is inspired by cinchona-derived sulfonamides
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Published 31 Jan 2018

Nucleophilic fluoroalkylation/cyclization route to fluorinated phthalides

  • Masanori Inaba,
  • Tatsuya Sakai,
  • Shun Shinada,
  • Tsuyuka Sugiishi,
  • Yuta Nishina,
  • Norio Shibata and
  • Hideki Amii

Beilstein J. Org. Chem. 2018, 14, 182–186, doi:10.3762/bjoc.14.12

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  • ). Previously, Shibata et al. reported a cinchona alkaloid/Me4NF-catalyzed nucleophilic enantioselective trifluoromethylation of carbonyl compounds [33][34][35]. Initially, we tried to conduct the reaction of 2-cyanobenzaldehyde (2) with CF3–SiMe3 in the presence of cinchona alkaloids 9/TMAF combination (Table
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Published 19 Jan 2018
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