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Search for "couplings" in Full Text gives 273 result(s) in Beilstein Journal of Organic Chemistry. Showing first 200.

Mechanisms for radical reactions initiating from N-hydroxyphthalimide esters

  • Carlos R. Azpilcueta-Nicolas and
  • Jean-Philip Lumb

Beilstein J. Org. Chem. 2024, 20, 346–378, doi:10.3762/bjoc.20.35

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  • reaction classes, we discuss the utility of the NHPI esters, with an eye towards their continued development in complexity-generating transformations. Keywords: decarboxylative couplings; mechanisms; NHPI-esters; radical reactions; Introduction The historical challenges of using radicals in synthetic
  • phthalimidyl anion would generate the aminoalkylation product 119, completing the catalytic cycle. In addition to this aminoalkylation method, the synthetic utility of radical intermediates derived from NHPI esters under photoinduced Pd-catalysis has been demonstrated in Heck-type couplings [81][82] and in the
  • decarboxylative cross-coupling (DCC) of NHPI esters with organometallic reagents, resembling classic Kumada, Negishi, and Suzuki couplings, has been enabled by nickel (Ni), cobalt (Co), iron (Fe), and copper (Cu) catalysts [84][85][86][87][88][89][90][91] (Scheme 23A). The typical mechanism begins by
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Published 21 Feb 2024

Facile approach to N,O,S-heteropentacycles via condensation of sterically crowded 3H-phenoxazin-3-one with ortho-substituted anilines

  • Eugeny Ivakhnenko,
  • Vasily Malay,
  • Pavel Knyazev,
  • Nikita Merezhko,
  • Nadezhda Makarova,
  • Oleg Demidov,
  • Gennady Borodkin,
  • Andrey Starikov and
  • Vladimir Minkin

Beilstein J. Org. Chem. 2024, 20, 336–345, doi:10.3762/bjoc.20.34

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  • structure, 3H-phenoxazin-3-ones can easily be accessed through oxidative couplings of o-aminophenols [3][4] or N-aryl-o-benzoquinone imines [5][6]. Further, they can serve as efficient precursors of pentacyclic N,O-heterocyclic compounds that possess promising properties for application in fluorescent
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Published 21 Feb 2024

Metal-catalyzed coupling/carbonylative cyclizations for accessing dibenzodiazepinones: an expedient route to clozapine and other drugs

  • Amina Moutayakine and
  • Anthony J. Burke

Beilstein J. Org. Chem. 2024, 20, 193–204, doi:10.3762/bjoc.20.19

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  • performing the reaction of o-phenylenediamine (1a) with 2-bromophenylboronic acid (7) in the presence of Cu(OAc)2, Et3N as base in DCM at 50 °C (entry 1, Table 4), and gratifingly under these conditions, the reaction afforded compound 3a in 48% yield. The Chan–Lam couplings were undertaken under an aerobic
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Published 31 Jan 2024

Multi-redox indenofluorene chromophores incorporating dithiafulvene donor and ene/enediyne acceptor units

  • Christina Schøttler,
  • Kasper Lund-Rasmussen,
  • Line Broløs,
  • Philip Vinterberg,
  • Ema Bazikova,
  • Viktor B. R. Pedersen and
  • Mogens Brøndsted Nielsen

Beilstein J. Org. Chem. 2024, 20, 59–73, doi:10.3762/bjoc.20.8

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  • variety of reactions; that are, phosphite- or Lawesson’s reagent-mediated olefination reactions (to introduce DTF motifs), Ramirez/Corey–Fuchs dibromo-olefinations followed by Sonogashira couplings (to introduce enediynes motifs), and Knoevenagel condensations (to introduce the vinylic diester motif). By
  • various elaborate systems [24][25][26][27]. Next, we wanted to explore IF-DTFs as motifs for acetylenic scaffolding (Scheme 4). Starting from IF-DTF building block 6, dibromo-olefinated compound 18 was obtained by a Ramirez/Corey–Fuchs reaction. Two-fold Sonogashira couplings with trimethylsilylacetylene
  • Sonogashira couplings of compound 25 with triisopropylsilylacetylene and ((2-ethynylphenyl)ethynyl)triisopropylsilane yielded compounds 26 and 27, respectively. A two-fold, intramolecular Glaser–Hay coupling of compound 27 (after desilylation) was attempted under the conditions that were successful in the
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Published 15 Jan 2024

Recent advancements in iodide/phosphine-mediated photoredox radical reactions

  • Tinglan Liu,
  • Yu Zhou,
  • Junhong Tang and
  • Chengming Wang

Beilstein J. Org. Chem. 2023, 19, 1785–1803, doi:10.3762/bjoc.19.131

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  • novel metallaphotoredox catalysis by combining the NaI/PPh3 photoredox catalyst with a Cu(I) catalyst to accomplish diverse C–O/N cross-couplings of alkyl N-hydroxyphthalimide esters 3 with various phenols/secondary amines 30 (Scheme 13) [24]. It was anticipated the utilization of computational methods
  • bioisostere for a range of functional groups (such as CH2OH, CH2OCH3, CH2NH2, and CH2SH). Among the various methods available, radical-involving cross-couplings have proven to be the most effective [48][49]. However, the generation of the CH2F radical remains to be a challenging task. Therefore, there is an
  • alkylation employing ammonium iodide. NaI/PPh3/CuBr cooperative catalysis for photocatalytic C(sp3)–O/N cross-coupling reactions. Proposed mechanism of NaI/PPh3/CuBr cooperative catalysis for photocatalytic C(sp3)–O/N cross-couplings. Photocatalytic decarboxylative [3 + 2]/[4 + 2] annulation between enynals
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Published 22 Nov 2023

Radical chemistry in polymer science: an overview and recent advances

  • Zixiao Wang,
  • Feichen Cui,
  • Yang Sui and
  • Jiajun Yan

Beilstein J. Org. Chem. 2023, 19, 1580–1603, doi:10.3762/bjoc.19.116

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  • couplings in PATs. Scheme 10 redrawn from [79]. General thiol-ene photopolymerization process. Scheme 11 redrawn from [81]. (a) Three generations of Grubbs catalysts. (b) Proposed mechanism for photo-ROMP via a reductive quenching pathway and (c, d) chemical structures of the (c) initiators and (d) monomers
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Published 18 Oct 2023

C–H bond functionalization: recent discoveries and future directions

  • Indranil Chatterjee

Beilstein J. Org. Chem. 2023, 19, 1568–1569, doi:10.3762/bjoc.19.114

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  • well as famous Noble-prize-winning cross-couplings, therefore approaching another step up towards sustainability. Likewise, a free-radical process is also a classical way to functionalize nonactivated C−H bonds in which site selectivity arises either from the relative strength of the C−H bonds or from
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Published 17 Oct 2023

Exploring the role of halogen bonding in iodonium ylides: insights into unexpected reactivity and reaction control

  • Carlee A. Montgomery and
  • Graham K. Murphy

Beilstein J. Org. Chem. 2023, 19, 1171–1190, doi:10.3762/bjoc.19.86

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  • metal-like, orchestrating ligand couplings within its ligand sphere. Iodonium ylides were recently confirmed to possess two σ-holes of differing strengths, and theories about these ylides react now explicitly invoke halogen bonding and EDA complexes between iodine and Lewis basic reactants. Many of
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Published 07 Aug 2023

Photoredox catalysis harvesting multiple photon or electrochemical energies

  • Mattia Lepori,
  • Simon Schmid and
  • Joshua P. Barham

Beilstein J. Org. Chem. 2023, 19, 1055–1145, doi:10.3762/bjoc.19.81

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  • 2.1.1 C(sp2)–X activation: In the rise of visible light-mediated PRC, the generation of aryl radicals for C(sp2)–C(sp2/3) couplings under mild conditions (room temperature, visible light activation of a catalyst) was heavily investigated [34][35][36]. However, initially the procedures were generally
  • (pinacolato)diboron (B2pin2) as trapping agents for C(sp2)–Het(Arene) couplings (Figure 9B). The successful activation of electron-neutral and electron-rich aryl halides via conPET mostly remained an unsolved challenge until the Nicewicz group in 2020 disclosed a modified acridinium (Fukuzumi) salt Mes-Acr
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Published 28 Jul 2023

Eschenmoser coupling reactions starting from primary thioamides. When do they work and when not?

  • Lukáš Marek,
  • Jiří Váňa,
  • Jan Svoboda and
  • Jiří Hanusek

Beilstein J. Org. Chem. 2023, 19, 808–819, doi:10.3762/bjoc.19.61

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  • virtually opposite to the order of ECR reactivity. Thus, the substrates with the lowest barriers for ECR couplings have the highest energies for the Hantzsch reaction and vice versa. The calculated reaction profiles show that there are two factors that influence whether the reaction gives ECR or Hantzsch
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Published 09 Jun 2023

Bromination of endo-7-norbornene derivatives revisited: failure of a computational NMR method in elucidating the configuration of an organic structure

  • Demet Demirci Gültekin,
  • Arif Daştan,
  • Yavuz Taşkesenligil,
  • Cavit Kazaz,
  • Yunus Zorlu and
  • Metin Balci

Beilstein J. Org. Chem. 2023, 19, 764–770, doi:10.3762/bjoc.19.56

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  • temperatures yielding mixtures of addition products. The structural elucidations of the formed compounds were achieved by NMR spectroscopy. Particularly, the γ-gauche effect and long-range couplings were instrumental in assigning the stereochemistry of the adducts. However, in a recent paper, Novitskiy and
  • atoms were determined by measuring the couplings between the relevant protons. Proton–proton couplings beyond the three bonds are observed frequently in some strained bicyclic compounds. The long-range coupling exists in a zigzag arrangement (Figure 2). In the case of norbornane if the bonding
  • arrangement of the protons meets the W or M criterion as shown below, long-range couplings between the protons Ha and Hb as well as between the protons Ha and Hc are observed [5][6]. However, no coupling is observed between the protons Ha and Hd. These values are extremely important for determining the
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Published 02 Jun 2023

C3-Alkylation of furfural derivatives by continuous flow homogeneous catalysis

  • Grédy Kiala Kinkutu,
  • Catherine Louis,
  • Myriam Roy,
  • Juliette Blanchard and
  • Julie Oble

Beilstein J. Org. Chem. 2023, 19, 582–592, doi:10.3762/bjoc.19.43

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  • synthesis has increased dramatically and has rapidly become a routine tool for classical synthesis [26][27][28][29]. In particular, many efforts have been devoted to the development of flow alternatives for transition-metal-catalyzed cross-couplings [30] and for some C–H functionalizations [31
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Published 03 May 2023
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  • conformation was determined by calculation using force field methods (MMFF94 [16]) and is shown in Figure S2 of Supporting Information File 1. Key NOE couplings were observed between bridgehead H-8a, H-4a and H-4. The latter also couples with the methyl group at C-1, indicating a cis-decalin configuration with
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Published 16 Feb 2023

Total synthesis of insect sex pheromones: recent improvements based on iron-mediated cross-coupling chemistry

  • Eric Gayon,
  • Guillaume Lefèvre,
  • Olivier Guerret,
  • Adrien Tintar and
  • Pablo Chourreu

Beilstein J. Org. Chem. 2023, 19, 158–166, doi:10.3762/bjoc.19.15

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  • insect sex pheromones as an alternative to conventional pesticides is in constant growth. In this report, we discuss the recent contributions brought by our groups in the field of iron-catalyzed cross-couplings applied to the synthesis of insect pheromones. The pivotal question of the development of
  • cross coupling reaction developed by Kochi, leading to better yields, with no need to use an excess of one of the coupling partners (Scheme 2b) [12]. The yields obtained using this ligand-free method are comparable to those obtained in recent palladium-mediated alkyl–vinyl cross-couplings using
  • reactions, which witnessed considerable development in the last two decades [14], several cross-coupling methodologies involving soft nucleophiles, such as iron-mediated Suzuki–Miyaura cross-couplings, being reported [15]. The introduction of alkyl–alkenyl linkage by means of iron-catalyzed cross-coupling
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Published 14 Feb 2023

1,4-Dithianes: attractive C2-building blocks for the synthesis of complex molecular architectures

  • Bram Ryckaert,
  • Ellen Demeyere,
  • Frederick Degroote,
  • Hilde Janssens and
  • Johan M. Winne

Beilstein J. Org. Chem. 2023, 19, 115–132, doi:10.3762/bjoc.19.12

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  • -formation processes (Scheme 12) [82][83]. These recently obtained results indicate that a sulfur-stabilized carbon radical derived from 1,4-dithiane (1) is a viable reaction intermediate, opening up the use of 1,4-dithianes in various free radical-type cross-couplings. 5 Synthetic equivalents of the allyl
  • untapped potential in this area of research, and expect the utility of these building blocks to grow in the coming years. In particular, the recently established options to elaborate and functionalize 1,4-dithianes using mild transition-metal-catalyzed couplings, and their use in cycloaddition reactions
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Published 02 Feb 2023

Synthesis of the biologically important dideuterium-labelled adenosine triphosphate analogue ApppI(d2)

  • Petri A. Turhanen

Beilstein J. Org. Chem. 2022, 18, 1466–1470, doi:10.3762/bjoc.18.153

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  • used in the 13C NMR spectrum for characterization is mentioned in the data reported for ApppI(d2) below. The nJCP couplings were calculated from the carbon spectra, with the coupling constant given in parentheses in Hz. The HPCCC purification method has previously been reported elsewhere and was used
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Published 14 Oct 2022

Dissecting Mechanochemistry III

  • Lars Borchardt and
  • José G. Hernández

Beilstein J. Org. Chem. 2022, 18, 1454–1456, doi:10.3762/bjoc.18.150

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  • an appropriate oxidant for C–N couplings towards the synthesis of 1,2-disubstituted benzimidazoles and quinazolin-4(3H)-one derivatives under mechanochemical conditions, as evidenced by Mal and co-workers (Scheme 5) [9]. However, the findings within Mechanochemistry III span beyond the synthesis or
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Published 12 Oct 2022

Naphthalimide-phenothiazine dyads: effect of conformational flexibility and matching of the energy of the charge-transfer state and the localized triplet excited state on the thermally activated delayed fluorescence

  • Kaiyue Ye,
  • Liyuan Cao,
  • Davita M. E. van Raamsdonk,
  • Zhijia Wang,
  • Jianzhang Zhao,
  • Daniel Escudero and
  • Denis Jacquemin

Beilstein J. Org. Chem. 2022, 18, 1435–1453, doi:10.3762/bjoc.18.149

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  • characteristic TADF lifetimes (Figure 4b and 4e). Clearly, besides the conformational flexibility, other factors do play a role in the photophysical properties of the dyad, i.e., the magnitudes of CT/3LE energy gap, and related spin–vibronic couplings. Increasing the CT state energy either through oxidation of
  • than the 1CT state (2.60 eV), while 3CT remains slightly lower in energy (2.57 eV). This has some important consequences on the TADF mechanisms. Table 5 lists spin–orbit couplings matrix elements (SOCMEs) between 1CT, 3LE, and 3CT states. The SOCMEs between 1CT and 3CT are small, 0.03 cm−1 at most
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Published 11 Oct 2022

Polymer and small molecule mechanochemistry: closer than ever

  • José G. Hernández

Beilstein J. Org. Chem. 2022, 18, 1225–1235, doi:10.3762/bjoc.18.128

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  • polymerizations [57][58][59], arylations and borylations [60], trifluoromethylations [61], as well as dehydrogenative couplings and cycloadditions [62], among others [63][64] in which mechanically polarized piezoelectric materials triggered redox chemistry. Alternative strategies to transduce mechanical force to
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Published 14 Sep 2022

Derivatives of benzo-1,4-thiazine-3-carboxylic acid and the corresponding amino acid conjugates

  • Péter Kisszékelyi,
  • Tibor Peňaška,
  • Klára Stankovianska,
  • Mária Mečiarová and
  • Radovan Šebesta

Beilstein J. Org. Chem. 2022, 18, 1195–1202, doi:10.3762/bjoc.18.124

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  • , entries 1 and 4). Application of ligand (S,S)-methyl-DUPHOS (L3) gave increased ee in the hydrogenation reaction, but the best result (90% ee) was achieved using 6 mol % Josiphos ligand L2 at 35 °C. Following the synthesis of 3-propylnorleucin methyl ester (16a), we carried on with the amine couplings
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Published 09 Sep 2022

Heterogeneous metallaphotoredox catalysis in a continuous-flow packed-bed reactor

  • Wei-Hsin Hsu,
  • Susanne Reischauer,
  • Peter H. Seeberger,
  • Bartholomäus Pieber and
  • Dario Cambié

Beilstein J. Org. Chem. 2022, 18, 1123–1130, doi:10.3762/bjoc.18.115

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  • Berlin, Germany 10.3762/bjoc.18.115 Abstract Metallaphotoredox catalysis is a powerful and versatile synthetic platform that enables cross-couplings under mild conditions without the need for noble metals. Its growing adoption in drug discovery has translated into an increased interest in sustainable
  • catalytic approaches [9]. Especially the combination with other transition metal catalysts (metallaphotoredox catalysis), such as nickel complexes, resulted in a vast number of new methods to achieve cross-couplings under mild conditions [10]. However, the conditions of these methods are often hard to
  • light-mediated carbon–heteroatom cross-couplings of sodium sulfinates, carboxylic acids and sulphonamides with aryl halides (Figure 2) [28]. Although recyclable, batch reactions are characterized by long reaction times (24 h). Here, we present a detailed investigation of a continuous-flow strategy for
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Published 29 Aug 2022

Introducing a new 7-ring fused diindenone-dithieno[3,2-b:2',3'-d]thiophene unit as a promising component for organic semiconductor materials

  • Valentin H. K. Fell,
  • Joseph Cameron,
  • Alexander L. Kanibolotsky,
  • Eman J. Hussien and
  • Peter J. Skabara

Beilstein J. Org. Chem. 2022, 18, 944–955, doi:10.3762/bjoc.18.94

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  • previously by other groups [38][39], however, we here use a different protocol. Intermediates 25 or 26 were reacted in Suzuki–Miyaura couplings [36] with commercially available methyl 5-bromo-2-iodobenzoate [40], to obtain the key intermediate dimethyl 6,6’-(dithieno[3,2-b:2’,3’-d]thiophene-2,6-diyl)bis(3
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Published 01 Aug 2022

Comparative study of thermally activated delayed fluorescent properties of donor–acceptor and donor–acceptor–donor architectures based on phenoxazine and dibenzo[a,j]phenazine

  • Saika Izumi,
  • Prasannamani Govindharaj,
  • Anna Drewniak,
  • Paola Zimmermann Crocomo,
  • Satoshi Minakata,
  • Leonardo Evaristo de Sousa,
  • Piotr de Silva,
  • Przemyslaw Data and
  • Youhei Takeda

Beilstein J. Org. Chem. 2022, 18, 459–468, doi:10.3762/bjoc.18.48

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  • , the T1 and T2 states on the D–A–D molecule POZ-DBPHZ display a mixed CT/LE character. It is known that having two states with different electronic characters allows for larger spin–orbit couplings, so we would expect these couplings to be larger in the case of the D–A molecule when comparing with the
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Published 25 Apr 2022

Borylated norbornadiene derivatives: Synthesis and application in Pd-catalyzed Suzuki–Miyaura coupling reactions

  • Robin Schulte and
  • Heiko Ihmels

Beilstein J. Org. Chem. 2022, 18, 368–373, doi:10.3762/bjoc.18.41

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  • -dioxaborolane, whose reactivity in Suzuki–Miyaura couplings has not been investigated, so far [32][33]. To explore the suitability of borylated norbornadienes for Suzuki–Miyaura coupling reactions and thus to provide new useful building blocks for the modular construction of norbornadiene derivatives
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Published 01 Apr 2022

Earth-abundant 3d transition metals on the rise in catalysis

  • Nikolaos Kaplaneris and
  • Lutz Ackermann

Beilstein J. Org. Chem. 2022, 18, 86–88, doi:10.3762/bjoc.18.8

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  • alternatives. Furthermore, metal-catalyzed cross-couplings do require prefunctionalizations on both substrates and generate stoichiometric quantities of undesired chemical waste, thus reducing the sustainability of these catalytic transformations. To address these major limitations, the past decades have
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Published 07 Jan 2022
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