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Search for "ketimine" in Full Text gives 29 result(s) in Beilstein Journal of Organic Chemistry.

Asymmetric synthesis of β-amino cyanoesters with contiguous tetrasubstituted carbon centers by halogen-bonding catalysis with chiral halonium salt

  • Yasushi Yoshida,
  • Maho Aono,
  • Takashi Mino and
  • Masami Sakamoto

Beilstein J. Org. Chem. 2025, 21, 547–555, doi:10.3762/bjoc.21.43

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  • developed chiral halonium salts and applied them to asymmetric reactions such as vinylogous Mannich reactions of cyanomethylcoumarins 6 with isatin-derived ketimines 7 [33][35] and 1,2-addition reaction of thiols to ketimine [34], which formed the corresponding products 8 in high yields with high to
  • catalysis (Figure 2c). Results and Discussion Chiral halonium salts 9a–c were prepared according to our previously reported methods [33]. The Mannich reaction of ketimine 7a and cyanoester 16a was selected as a benchmark, and catalyst screening was conducted (Scheme 1). The reaction was carried out with 1.0
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Published 12 Mar 2025

Recent advances in electrochemical copper catalysis for modern organic synthesis

  • Yemin Kim and
  • Won Jun Jang

Beilstein J. Org. Chem. 2025, 21, 155–178, doi:10.3762/bjoc.21.9

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  • enantioselectivity. First, the reaction of ketimine ester 33 and 2,3-dimethylhydroquinone at 10 °C provided the chiral 1,4-addition product 35 via dynamic kinetic asymmetric transformation (DyKAT). Conversely, when the reaction was performed at −10 °C, the reaction pathway switched from DyKAT to kinetic resolution
  • (KR) of the racemic ketimine ester, providing the same chiral product 35 with recovered enantioenriched starting material. Additionally, when a 1-naphthyl ester was used instead of a methyl ester at −10 °C, 1,4-addition followed by intramolecular tandem annulation generated the corresponding chiral
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Published 16 Jan 2025

Non-covalent organocatalyzed enantioselective cyclization reactions of α,β-unsaturated imines

  • Sergio Torres-Oya and
  • Mercedes Zurro

Beilstein J. Org. Chem. 2024, 20, 3221–3255, doi:10.3762/bjoc.20.268

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  • : the azlactone is activated by the chiral phosphoric acid to generate its active enol form, while at the same time the chiral phosphoric acid mediates the in situ formation of the α,β-unsaturated N–H ketimine, occurring through the formation of an orthoester intermediate A. Then, the chiral phosphoric
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Published 10 Dec 2024

Advances in radical peroxidation with hydroperoxides

  • Oleg V. Bityukov,
  • Pavel Yu. Serdyuchenko,
  • Andrey S. Kirillov,
  • Gennady I. Nikishin,
  • Vera A. Vil’ and
  • Alexander O. Terent’ev

Beilstein J. Org. Chem. 2024, 20, 2959–3006, doi:10.3762/bjoc.20.249

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Published 18 Nov 2024

A review of recent advances in electrochemical and photoelectrochemical late-stage functionalization classified by anodic oxidation, cathodic reduction, and paired electrolysis

  • Nian Li,
  • Ruzal Sitdikov,
  • Ajit Prabhakar Kale,
  • Joost Steverlynck,
  • Bo Li and
  • Magnus Rueping

Beilstein J. Org. Chem. 2024, 20, 2500–2566, doi:10.3762/bjoc.20.214

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  • utilizing a Rh(III) catalyst [54]. The critical step in this process is the anodic oxidation of Rh(III) to a high-valent Rh complex on the RVC anode. This transformation necessitates the presence of a directing group in the substrate molecule. Cyclic ketimine was found to direct ortho-C–H phosphorylation
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Published 09 Oct 2024

Synthesis of spiropyridazine-benzosultams by the [4 + 2] annulation reaction of 3-substituted benzoisothiazole 1,1-dioxides with 1,2-diaza-1,3-dienes

  • Wenqing Hao,
  • Long Wang,
  • Jinlei Zhang,
  • Dawei Teng and
  • Guorui Cao

Beilstein J. Org. Chem. 2024, 20, 280–286, doi:10.3762/bjoc.20.29

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  • ketimine and its subsequent [4 + 2] annulation reaction with 1,2-diaza-1,3-diene in the presence of Et3N (2.0 equiv) in diethyl ether at room temperature (Table 1, entry 1). However, no product was detected under these conditions. We then replaced diethyl ether with toluene, which resulted in the desired
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Published 14 Feb 2024
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  • reaction proceeding through aza-Friedel–Crafts reaction and lactonization steps. Main focus of this article was to demonstrate a racemic process between α-naphthol or phenol derivatives and in situ-generated N-acetyl ketimine from methyl 2-acetamidoacrylate (18) in the course of preparing 3-NHAc
  • enantiomeric excesses. However, N-unsubstituted 49 (R1 = H) resulted in a much diminished stereoselectivity. As the electrophilic partner, isatin-derived ketimine was also utilized which furnished the product with 68% enantiomeric excess. Replacement of the nucleophile in this methodology for substrate scope
  • designed between sesamol (132) and N-Boc-protected ketimine 131 in the presence of T3 as catalyst to introduce the electrophile at the ortho-position with respect to the phenolic OH group. The aza-Friedel–Crafts product was obtained with 94% yield and converted into triflate 133 with 74% yield and 99% ee
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Published 28 Jun 2023

Bioinspired tetraamino-bisthiourea chiral macrocycles in catalyzing decarboxylative Mannich reactions

  • Hao Guo,
  • Yu-Fei Ao,
  • De-Xian Wang and
  • Qi-Qiang Wang

Beilstein J. Org. Chem. 2022, 18, 486–496, doi:10.3762/bjoc.18.51

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  • and activation ability. Catalytic reaction optimization The synthesized macrocycles were then applied as catalysts in the decarboxylative addition of malonic acid half thioesters (MAHTs) to isatin-derived ketimines [48]. The reaction between ketimine 6a and MAHT 7a was initially performed in THF at
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Published 02 May 2022

Unexpected chiral vicinal tetrasubstituted diamines via borylcopper-mediated homocoupling of isatin imines

  • Marco Manenti,
  • Leonardo Lo Presti,
  • Giorgio Molteni and
  • Alessandra Silvani

Beilstein J. Org. Chem. 2022, 18, 303–308, doi:10.3762/bjoc.18.34

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  • diffraction analysis and proved to be single diastereoisomers and atropisomers. A plausible mechanism for the one-pot Cu(II)-catalyzed Bpin addition to the isatin-derived ketimine substrate and subsequent homocoupling is described. Keywords: atropoisomer; bis(pinacolato)diboron; 3,3′-bisoxindole; N-tert
  • -butanesulfinyl ketimine; homocoupling; Introduction As bioisosteres of carboxylic acid derivatives, boronic acids have recently emerged as a novel chemotype in drug design, with a number of boron-containing compounds recently being approved by the FDA [1][2][3][4]. In particular, α- and β-aminoboronic acids are
  • . Results and Discussion We began our investigation using the known (R)-1-methylisatin-derived N-tert-butanesulfinyl ketimine 1a, bis(pinacolato)diboron, CuSO4/(Cy)3P catalyst and benzylamine, as reported in Scheme 1. The first reaction was carried out at room temperature in toluene/water (5:1), as
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Published 10 Mar 2022

New efficient synthesis of polysubstituted 3,4-dihydroquinazolines and 4H-3,1-benzothiazines through a Passerini/Staudinger/aza-Wittig/addition/nucleophilic substitution sequence

  • Long Zhao,
  • Mao-Lin Yang,
  • Min Liu and
  • Ming-Wu Ding

Beilstein J. Org. Chem. 2022, 18, 286–292, doi:10.3762/bjoc.18.32

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  • of their derivatives [12][13][14][15][16][17][18][19][20][21][22]. For example (Scheme 1), a one-pot Tf2O-mediated assembly of amides, amines, and ketones provided 3,4-dihydroquinazolines in good yields via successive triflic anhydride-mediated amide dehydration, ketimine addition, and Pictet
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Published 04 Mar 2022

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

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  • -butanesulfinyl ketimine condensation (Scheme 2) [21]. Mechanism of addition of nucleophiles to N-sulfinyl imines The p-toluenesulfinamide 5 was first described by Davis and co-workers in a racemic form [22], and subsequently, the compound was prepared and isolated as a single enantiomer [23][24], becoming an
  • is present in the reaction medium [74]. The trifluoromethyl group occupies an equatorial position to avoid electrostatic repulsion with the lone pair of electrons of the sulfinyl group. The nucleophilic attack took place to the Si face of the ketimine 37 (Scheme 13). Recently, Yang and co-workers
  • the stereoselective synthesis of spiro β-lactam 57 from chiral (RS)-N-tert-butanesulfinyl isatin ketimine 53 (R1 = H), with a bulky trityl protecting group bonded to the nitrogen indolic atom (Tr = triphenylmethyl), and ethyl bromoacetate. The Zn/Cu-mediated Reformatsky-type reaction furnished
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Published 12 May 2021

Chan–Evans–Lam N1-(het)arylation and N1-alkеnylation of 4-fluoroalkylpyrimidin-2(1H)-ones

  • Viktor M. Tkachuk,
  • Oleh O. Lukianov,
  • Mykhailo V. Vovk,
  • Isabelle Gillaizeau and
  • Volodymyr A. Sukach

Beilstein J. Org. Chem. 2020, 16, 2304–2313, doi:10.3762/bjoc.16.191

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  • required for the coupling are not tolerated with the highly electrophilic ketimine moiety of 4-trifluoromethylpyrimidin-2(1H)-ones. The CEL reaction was successfully applied in the N-arylation of many heterocyclic systems [35][36][37] including non-fluorinated pyrimidin-2(1H)-ones [38][39] under mild
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Published 17 Sep 2020

DABCO- and DBU-promoted one-pot reaction of N-sulfonyl ketimines with Morita–Baylis–Hillman carbonates: a sequential approach to (2-hydroxyaryl)nicotinate derivatives

  • Soumitra Guin,
  • Raman Gupta,
  • Debashis Majee and
  • Sampak Samanta

Beilstein J. Org. Chem. 2018, 14, 2771–2778, doi:10.3762/bjoc.14.254

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  • reaction between 4-methyl-N-sulfonyl ketimine 1a and several aryl-substituted MBH carbonates having electron donating (Me, MeO and BnO) and withdrawing substituents (F, Br, CN and NO2) on the benzene rings proceeded smoothly under the present conditions. The results showed that electron donating
  • better yields than the former one. By this C–C/C–N bonds forming procedure, N-sulfonyl ketimine derived from a bulky α-naphthol moiety was found to be a suitable coupling reagent, leading to the corresponding α-naphthol-substituted nicotinate derivatives 5ea and 5ee in 71% and 74% yields, respectively
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Published 02 Nov 2018

Hydroarylations by cobalt-catalyzed C–H activation

  • Rajagopal Santhoshkumar and
  • Chien-Hong Cheng

Beilstein J. Org. Chem. 2018, 14, 2266–2288, doi:10.3762/bjoc.14.202

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  • (Scheme 20b) [66]. Moreover, the Co-catalyzed hydroarylation of styrene with ketimine or aldimine proceeded without Grignard reagent using Mg metal as the reductant [67]. Recently, N–H imines 9d were also employed for the hydroarylation reaction with styrenes, giving a branched-selective hydroarylation
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Published 29 Aug 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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  • tolerated at the 5, 6 or 7-position of the isatin aryl moiety (R2). The lowest yield (46%) was obtained in the reaction of a disubstituted ketimine (R2 = 5,7-Me2). It must be noted that this methodology represented the first enantioselective addition of hydroxyquinolines to imines. Enantioselective aza
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Published 06 Jun 2018

Regioselective decarboxylative addition of malonic acid and its mono(thio)esters to 4-trifluoromethylpyrimidin-2(1H)-ones

  • Sergii V. Melnykov,
  • Andrii S. Pataman,
  • Yurii V. Dmytriv,
  • Svitlana V. Shishkina,
  • Mykhailo V. Vovk and
  • Volodymyr A. Sukach

Beilstein J. Org. Chem. 2017, 13, 2617–2625, doi:10.3762/bjoc.13.259

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  • -containing heterocyclic compounds [24][25][26][27][28][29]. It should be noted that the presence of a strong electron-withdrawing trifluoromethyl group is responsible for the sufficient reactivity of the electrophilic ketimine function with various carbon nucleophiles in these reactions. Recently, the
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Published 07 Dec 2017

Enantioselective addition of diphenyl phosphonate to ketimines derived from isatins catalyzed by binaphthyl-modified organocatalysts

  • Hee Seung Jang,
  • Yubin Kim and
  • Dae Young Kim

Beilstein J. Org. Chem. 2016, 12, 1551–1556, doi:10.3762/bjoc.12.149

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  • initially investigated a reaction system with ketimine 1a derived from N-allylisatin and diphenyl phosphonate (2) with organocatalyst in the presence of 4 Å molecular sieves. We first surveyed the effect of the structure of bifunctional organocatalysts I–VI (Figure 1) on enantioselectivity in ethyl acetate
  • presence of 10 mol % of catalyst III together with ketimine 1a and diphenyl phosphonate (2). We obtained excellent results in ethyl acetate (85% yield, 90% ee, Table 1, entry 3), while a slight decrease in enationselectivities was observed when dichloromethane, chloroform, tetrahydrofuran, toluene, and
  • -phosphonyl-substituted oxindole derivatives 3g–j in high yields (78–88%) with excellent enantioselectivities (98–99% ee) (Table 2, entries 7–10). Ketimine 1k containing an electron donating group gave the desired product 3k in high yield (79%) with excellent enantioselectivity (99% ee, Table 2, entry 11
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Published 20 Jul 2016

Multicomponent reactions: A simple and efficient route to heterocyclic phosphonates

  • Mohammad Haji

Beilstein J. Org. Chem. 2016, 12, 1269–1301, doi:10.3762/bjoc.12.121

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  • investigated by the use of structurally diverse diamines, ketones and phosphonates. While the reaction proceeded well with different amines and phosphonates, only the use of acetone as the ketone component afforded the corresponding benzodiazepinylphosphonates. With other ketones only ketimine intermediates
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Published 21 Jun 2016

Modular synthesis of the pyrimidine core of the manzacidins by divergent Tsuji–Trost coupling

  • Sebastian Bretzke,
  • Stephan Scheeff,
  • Felicitas Vollmeyer,
  • Friederike Eberhagen,
  • Frank Rominger and
  • Dirk Menche

Beilstein J. Org. Chem. 2016, 12, 1111–1121, doi:10.3762/bjoc.12.107

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  • alkaloids of marine origin. Additional features of this route include the stereoselective generation of the central amine core with an appending quaternary center by an asymmetric addition of a Grignard reagent to a chiral tert-butanesulfinyl ketimine following an optimized Ellman protocol and a cross
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Published 02 Jun 2016

Catalytic asymmetric synthesis of biologically important 3-hydroxyoxindoles: an update

  • Bin Yu,
  • Hui Xing,
  • De-Quan Yu and
  • Hong-Min Liu

Beilstein J. Org. Chem. 2016, 12, 1000–1039, doi:10.3762/bjoc.12.98

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Published 18 May 2016

Cupreines and cupreidines: an established class of bifunctional cinchona organocatalysts

  • Laura A. Bryant,
  • Rossana Fanelli and
  • Alexander J. A. Cobb

Beilstein J. Org. Chem. 2016, 12, 429–443, doi:10.3762/bjoc.12.46

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  • having a substituent at the 4-position of the ketimine. In a related study, Takizawa and co-workers demonstrated that the quinine derived organocatalyst, α-ICPN [23] produced the enantiomeric product in a similar process using acrolein 10 as the conjugate partner (Scheme 3b) [24]. Chen and co-workers
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Published 07 Mar 2016

Copper-catalyzed aerobic radical C–C bond cleavage of N–H ketimines

  • Ya Lin Tnay,
  • Gim Yean Ang and
  • Shunsuke Chiba

Beilstein J. Org. Chem. 2015, 11, 1933–1943, doi:10.3762/bjoc.11.209

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  • proceeded smoothly in Et2O at 80 °C in a sealed tube, generating N–H ketimine 1aa after protonation with MeOH. Subsequently, Cu(OAc)2 (20 mol %), 1,10-phen (20 mol %) and DMF (to 0.1 M final concentration) were added and stirred at room temperature under an air atmosphere (Scheme 4). Interestingly, no
  • formation of the desired 6-membered azaspirocycle 3a’ was observed, while oxaspirocyclohexadienone 3a, biaryl alkene 4a, and p-tolunitrile (5a) were isolated in 29%, 32%, and 86% yields, respectively (Scheme 4). Oxaspirocyclohexadienone 3a was formed through C–C bond cleavage from N–H ketimine intermediate
  • ). A proposed reaction mechanism for the formation of oxaspirocyclohexadienone 3a, alkene 4a, and p-tolunitrile (5a) are depicted in Scheme 5. Single-electron oxidation of N–H ketimine 1aa with higher valent Cu(II) species generated under the aerobic reaction conditions forms iminyl radical species A
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Published 19 Oct 2015

Synthesis of alpha-tetrasubstituted triazoles by copper-catalyzed silyl deprotection/azide cycloaddition

  • Zachary L. Palchak,
  • Paula T. Nguyen and
  • Catharine H. Larsen

Beilstein J. Org. Chem. 2015, 11, 1425–1433, doi:10.3762/bjoc.11.154

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  • ketimine is followed by stoichiometric alkynylation with a trimethylsilyl-protected alkynyllithium reagent. Removal of the silyl and sulfinyl protecting groups allows for CuAAC with a resin-bound azide. Acylation of the amine followed by dehydration yields the active alpha-tetrasubstituted triazole [7
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Published 14 Aug 2015

Multicomponent versus domino reactions: One-pot free-radical synthesis of β-amino-ethers and β-amino-alcohols

  • Bianca Rossi,
  • Nadia Pastori,
  • Simona Prosperini and
  • Carlo Punta

Beilstein J. Org. Chem. 2015, 11, 66–73, doi:10.3762/bjoc.11.10

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  • conditions, likely due to an enhanced steric hindrance in the formed ketimine. The same reaction occurred by replacing THF with 1,3-dioxolane, 1,4-dioxane, and diethyl ether, affording the corresponding products 1h, 1i, and 1j, respectively, with complete selectivity but lower yields. Finally, for the first
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Published 15 Jan 2015

Morita–Baylis–Hillman reaction of acrylamide with isatin derivatives

  • Radhey M. Singh,
  • Kishor Chandra Bharadwaj and
  • Dharmendra Kumar Tiwari

Beilstein J. Org. Chem. 2014, 10, 2975–2980, doi:10.3762/bjoc.10.315

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  • with acrylate and acrylonitrile has also been developed resulting in high product yields. Keywords: acrylamide; isatin; ketimine; Morita–Baylis–Hillman; phenol; Introduction The Morita–Baylis–Hillman (MBH) reaction is an important carbon–carbon bond-forming reaction [1][2][3]. It involves the
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Published 12 Dec 2014
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