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Search for "C–C bond" in Full Text gives 471 result(s) in Beilstein Journal of Organic Chemistry. Showing first 200.

A green, economical synthesis of β-ketonitriles and trifunctionalized building blocks from esters and lactones

  • Daniel P. Pienaar,
  • Kamogelo R. Butsi,
  • Amanda L. Rousseau and
  • Dean Brady

Beilstein J. Org. Chem. 2019, 15, 2930–2935, doi:10.3762/bjoc.15.287

Graphical Abstract
  • excess of reagents, hazardous, flammable, or toxic reagents and high temperatures are required, which, in turn, may be detrimental to more highly functionalized starting materials. Nevertheless, this reaction under milder conditions is a valuable CC bond-forming reaction for the preparation of β
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Published 06 Dec 2019

Palladium-catalyzed Sonogashira coupling reactions in γ-valerolactone-based ionic liquids

  • László Orha,
  • József M. Tukacs,
  • László Kollár and
  • László T. Mika

Beilstein J. Org. Chem. 2019, 15, 2907–2913, doi:10.3762/bjoc.15.284

Graphical Abstract
  • wide applicability from syntheses of common building blocks to agrochemicals, just to name a few advantages [4][5][6]. From the series of palladium-assisted CC bond formation, the Sonogashira coupling reaction has been identified as a viable synthetic method for the preparation of various alkenyl- and
  • air-stable and readily available PdCl2(PPh3)2 was selected as a catalyst precursor to facilitate CC bond couplings involving various iodoaromatic compounds (1a–l) and phenylacetylene (2a) in [TBP][4EtOV] in the absence of any additional ligands and auxiliary base at 55 °C for 3 h. In general, the
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Published 03 Dec 2019

Bacterial terpene biosynthesis: challenges and opportunities for pathway engineering

  • Eric J. N. Helfrich,
  • Geng-Min Lin,
  • Christopher A. Voigt and
  • Jon Clardy

Beilstein J. Org. Chem. 2019, 15, 2889–2906, doi:10.3762/bjoc.15.283

Graphical Abstract
  • the leaving pyrophosphate group and the nucleophilic alkenes in proximity to initiate the CC-bond forming, carbocation-mediated cascade reactions [10]. The hydrophobic binding pocket stabilizes the reaction intermediates and tames the propagation of carbocations through cation–π and other
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Published 29 Nov 2019

Arylisoquinoline-derived organoboron dyes with a triaryl skeleton show dual fluorescence

  • Vânia F. Pais,
  • Tristan Neumann,
  • Ignacio Vayá,
  • M. Consuelo Jiménez,
  • Abel Ros and
  • Uwe Pischel

Beilstein J. Org. Chem. 2019, 15, 2612–2622, doi:10.3762/bjoc.15.254

Graphical Abstract
  • the syn and anti atropisomers because of the slow rotation around the chiral axis at this temperature. Free rotation around the CC bond was observed at 80 °C and hence, variable-temperature 1H NMR studies showed coalescence of the signals to give an average spectrum (see Supporting Information File 1
  • hinders the free rotation around axis A (Scheme 3) of the compounds 16–19; therefore, complex mixtures of the syn/anti atropoisomers (0.45:0.55; syn:anti) were observed in NMR spectroscopy. To facilitate the CC bond rotation around axis B (Scheme 3) and simplify the NMR spectra, the measurements were
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Published 04 Nov 2019

Indium-mediated C-allylation of melibiose

  • Christian Denner,
  • Manuel Gintner,
  • Hanspeter Kählig and
  • Walther Schmid

Beilstein J. Org. Chem. 2019, 15, 2458–2464, doi:10.3762/bjoc.15.238

Graphical Abstract
  • the elongated unit at the reducing end of the disaccharide. Keywords: carbohydrates; CC bond formation; indium-mediated allylation; melibiose; ozonolysis; Introduction The tin and indium-mediated allylation (IMA) proved to be useful synthetic tools for the chain elongation of unprotected
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Published 16 Oct 2019

Combining the Ugi-azide multicomponent reaction and rhodium(III)-catalyzed annulation for the synthesis of tetrazole-isoquinolone/pyridone hybrids

  • Gerardo M. Ojeda,
  • Prabhat Ranjan,
  • Pavel Fedoseev,
  • Lisandra Amable,
  • Upendra K. Sharma,
  • Daniel G. Rivera and
  • Erik V. Van der Eycken

Beilstein J. Org. Chem. 2019, 15, 2447–2457, doi:10.3762/bjoc.15.237

Graphical Abstract
  • processes has remained underexploited [27]. Thus, we envisioned that the combination of an Ugi-azide-4CR with modern metal-catalyzed CC bond-forming methods would enable access to structurally novel compounds featuring hybrid heterocycle platforms. We focused on metal-catalyzed annulation approaches that
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Published 16 Oct 2019

Current understanding and biotechnological application of the bacterial diterpene synthase CotB2

  • Ronja Driller,
  • Daniel Garbe,
  • Norbert Mehlmer,
  • Monika Fuchs,
  • Keren Raz,
  • Dan Thomas Major,
  • Thomas Brück and
  • Bernhard Loll

Beilstein J. Org. Chem. 2019, 15, 2355–2368, doi:10.3762/bjoc.15.228

Graphical Abstract
  • deuterium labeling [33][34][35], to form the carbocation located at position C8 of dolabellatrienyl (B). By ring closure and formation of a novel CC bond the tricyclic 5–8–5 ring system (C) is established. F107, F149, and the pyrophosphate moiety stabilize the carbocation at position C3 (Scheme 2 and
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Published 02 Oct 2019

Mono- and bithiophene-substituted diarylethene photoswitches with emissive open or closed forms

  • A. Lennart Schleper,
  • Mariano L. Bossi,
  • Vladimir N. Belov and
  • Stefan W. Hell

Beilstein J. Org. Chem. 2019, 15, 2344–2354, doi:10.3762/bjoc.15.227

Graphical Abstract
  • highly fluorescent “closed” forms combine photochromic and fluorescent entities in one molecule [1] and contain a perfluorocyclopentene bridge linking two 2-alkyl-1-benzothiophene-1,1-oxide residues with a C=C bond via C-3 and C-3′ atoms [2][3]. The “open” form of the DAE core (see graphical abstract and
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Published 01 Oct 2019

Click chemistry towards thermally reversible photochromic 4,5-bisthiazolyl-1,2,3-triazoles

  • Chenxia Zhang,
  • Kaori Morinaka,
  • Mahmut Kose,
  • Takashi Ubukata and
  • Yasushi Yokoyama

Beilstein J. Org. Chem. 2019, 15, 2161–2169, doi:10.3762/bjoc.15.213

Graphical Abstract
  • are compared, the thermal back reaction rate of 3 is extremely faster than the others, although the central aromatic ring is common to these compounds. As shown in Table 4, neither electronic charge distribution on the carbon atoms (natural charge [42]) comprising the thermally breaking CC bond, its
  • bond to give the open form, as shown with the arrows. The resonance structures are stabilized more strongly when R is a cyano group so that the CC bond scission occurs easily. Thus, it is possible to control the rate of the thermal back reaction by: (1) changing the aromatic ring at the ethene moiety
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Published 13 Sep 2019

Characterization of two new degradation products of atorvastatin calcium formed upon treatment with strong acids

  • Jürgen Krauß,
  • Monika Klimt,
  • Markus Luber,
  • Peter Mayer and
  • Franz Bracher

Beilstein J. Org. Chem. 2019, 15, 2085–2091, doi:10.3762/bjoc.15.206

Graphical Abstract
  • /dehydration process in the side chain), treatment with conc. aqueous hydrochloric acid gave a complex, bridged molecule under CC-bond formation of the lactone moiety with the pyrrole, migration of the isopropyl group and loss of the carboxanilide residue. The novel degradation products were characterized by
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Published 02 Sep 2019

Regioselective Pd-catalyzed direct C1- and C2-arylations of lilolidine for the access to 5,6-dihydropyrrolo[3,2,1-ij]quinoline derivatives

  • Hai-Yun Huang,
  • Haoran Li,
  • Thierry Roisnel,
  • Jean-François Soulé and
  • Henri Doucet

Beilstein J. Org. Chem. 2019, 15, 2069–2075, doi:10.3762/bjoc.15.204

Graphical Abstract
  • methodology provides a straightforward access to several lilolidine derivatives from commercially available compounds via one, two or three C–H bond functionalization steps allowing to tune their biological properties. Keywords: catalysis: CC bond formation; C–H bond activation; lilolidine; palladium
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Published 29 Aug 2019

Synthesis of 1-azaspiro[4.4]nonan-1-oxyls via intramolecular 1,3-dipolar cycloaddition

  • Yulia V. Khoroshunova,
  • Denis A. Morozov,
  • Andrey I. Taratayko,
  • Polina D. Gladkikh,
  • Yuri I. Glazachev and
  • Igor A. Kirilyuk

Beilstein J. Org. Chem. 2019, 15, 2036–2042, doi:10.3762/bjoc.15.200

Graphical Abstract
  • vibrations and no bands that could be attributed to the vibrations of OH or NH groups. Besides that in the spectrum of compound 17, there are absorption bands near 3054 and 1620 cm−1, which denote the presence of a double C=C bond. To elucidate the structure, nitroxyl radical 17 was converted into
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Published 27 Aug 2019

Isolation and characterisation of irinans, androstane-type withanolides from Physalis peruviana L.

  • Annika Stein,
  • Dave Compera,
  • Bianka Karge,
  • Mark Brönstrup and
  • Jakob Franke

Beilstein J. Org. Chem. 2019, 15, 2003–2012, doi:10.3762/bjoc.15.196

Graphical Abstract
  • A (2). Our experiments suggest that irinan A (2) and most likely all androwithanolides are not isolation artefacts but true natural products, which require an oxidative enzyme to facilitate the CC bond cleavage. Future studies will shed light on the enzymatic basis of androwithanolide formation
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Published 23 Aug 2019

A metal-free approach for the synthesis of amides/esters with pyridinium salts of phenacyl bromides via oxidative C–C bond cleavage

  • Kesari Lakshmi Manasa,
  • Yellaiah Tangella,
  • Namballa Hari Krishna and
  • Mallika Alvala

Beilstein J. Org. Chem. 2019, 15, 1864–1871, doi:10.3762/bjoc.15.182

Graphical Abstract
  • of a CC bond followed by formation of a new C–N/C–O bond in the presence of K2CO3. Various pyridinium salts of phenacyl bromides can be readily transformed into a variety of amides and esters which is an alternative method for the conventional amidation and esterification in organic synthesis. High
  • intermediate A. The attack of the ortho-position of the pyridinium moiety by the nucleophilic oxygen of intermediate A is then proposed to generate cyclic oxazolopyridine intermediate B [42][43]. The intermediate B then undergoes a rearrangement to afford N-alkylated benzamide 3 via a CC bond cleavage with
  • pyridinium salts of phenacyl bromides for the construction of amides and esters in the presence of base via oxidative CC bond cleavage. The promising features of this methodology include the absence of a metal catalyst, employing a simple inorganic base and operational simplicity for application in organic
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Published 05 Aug 2019

Norbornadiene-functionalized triazatriangulenium and trioxatriangulenium platforms

  • Roland Löw,
  • Talina Rusch,
  • Tobias Moje,
  • Fynn Röhricht,
  • Olaf M. Magnussen and
  • Rainer Herges

Beilstein J. Org. Chem. 2019, 15, 1815–1821, doi:10.3762/bjoc.15.175

Graphical Abstract
  • triazatriangulenium ion 6 was synthesized according to a procedure of Laursen and Krebs [13]. The platform 6 was functionalized with norbornadiene 5 by deprotection of the acetylene with potassium hydroxide and in situ formation of the CC bond between the acetylene and the central C atom of the platform 6 to yield
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Published 30 Jul 2019

N-(1-Phenylethyl)aziridine-2-carboxylate esters in the synthesis of biologically relevant compounds

  • Iwona E. Głowacka,
  • Aleksandra Trocha,
  • Andrzej E. Wróblewski and
  • Dorota G. Piotrowska

Beilstein J. Org. Chem. 2019, 15, 1722–1757, doi:10.3762/bjoc.15.168

Graphical Abstract
  • sources and are known as precursors to tropane alkaloids [59]. Together with (−)-pseudohygroline (2S,2'R)-62 they were synthesized from a common intermediate (2S,1'R)-63 prepared from the aldehyde (2R,1'R)-6 by Wittig olefination [60] and a regioselective C=C bond reduction (Scheme 17) [61]. N-Methylation
  • MeBmt are rather challenging endeavor since these amino acids in addition to an E-configured C=C bond has three neighboring stereogenic centers. The starting aziridine aldehyde (2R,1'R)-6 already introduces the required configuration at C2 and the two other centers of chirality were created by the
  • . Dehydration of 170 was completed in the presence of acid. Catalytic hydrogenation of the C=C bond in 171 took place preferentially (9:1) from the less hindered side to finally give (3R,5S)-168 as the hydrochloride salt. Substituted imidazolin-2-ones are of interest as potential aminoacyl-tRNA synthase
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Published 23 Jul 2019

Recent advances on the transition-metal-catalyzed synthesis of imidazopyridines: an updated coverage

  • Gagandeep Kour Reen,
  • Ashok Kumar and
  • Pratibha Sharma

Beilstein J. Org. Chem. 2019, 15, 1612–1704, doi:10.3762/bjoc.15.165

Graphical Abstract
  • -catalyzed cross-coupling reactions have laid down the foundation of new CC bond formations [50][51]. A number of Pd-catalyzed organic reactions viz., C–N coupling, amination and intramolecular amidation, cyclization, and Suzuki–Miyaura coupling [52][53][54][55] have recently been reported in the literature
  • organic processes and have attracted considerable interest in this regard. Ru has efficiently catalyzed C–H activation reactions for CC bond formation, aza-Michael reactions and many more MCRs [27][76][77]. During the writing of this review, we came through the fact that ruthenium catalysts were mostly
  • –Villiger reactions, epoxidations of alkenes, intramolecular ring expansions, hydroaminations, and amination reactions and carbonyl–ene reactions for the formation of CC bond. Scandium-catalyzed reactions represented remarkable enantioselectivities [79][80][81]. Recently the group of Rani has developed fly
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Published 19 Jul 2019

Diazocine-functionalized TATA platforms

  • Roland Löw,
  • Talina Rusch,
  • Fynn Röhricht,
  • Olaf Magnussen and
  • Rainer Herges

Beilstein J. Org. Chem. 2019, 15, 1485–1490, doi:10.3762/bjoc.15.150

Graphical Abstract
  • bromotoluene 3 with TMS-protected acetylene 4 (95%). The CC bond formation of 5 and 6 to give dibenzoyl 7 was achieved with potassium butoxide and elemental bromine (9%) according to a literature procedure [27]. The para-ethynyldiazocine 8 was obtained by reduction of both nitro groups, followed by oxidation
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Published 05 Jul 2019

Synthesis of non-racemic 4-nitro-2-sulfonylbutan-1-ones via Ni(II)-catalyzed asymmetric Michael reaction of β-ketosulfones

  • Alexander N. Reznikov,
  • Anastasiya E. Sibiryakova,
  • Marat R. Baimuratov,
  • Eugene V. Golovin,
  • Victor B. Rybakov and
  • Yuri N. Klimochkin

Beilstein J. Org. Chem. 2019, 15, 1289–1297, doi:10.3762/bjoc.15.127

Graphical Abstract
  • ; Michael addition; nickel complexes; nitroalkenes; Introduction Sulfones are widely used in organic synthesis, particularly, in various reactions of C–C and C=C-bond formation [1][2][3][4]. The use of sulfones in Julia–Kocienski [1] and Ramberg–Bäcklund reactions [2] made this class of compounds
  • transition metal complexes. The preparation of hydroxy sulfones from β-ketosulfones in the presence of Ru [19][20], Ir [21] and Rh [22] complexes was described. Chiral sulfones were also obtained by hydrogenation of the C=C bond with α,β-unsaturated sulfones in the presence of Ir(I) complexes with P,N
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Published 12 Jun 2019

Alkylation of lithiated dimethyl tartrate acetonide with unactivated alkyl halides and application to an asymmetric synthesis of the 2,8-dioxabicyclo[3.2.1]octane core of squalestatins/zaragozic acids

  • Herman O. Sintim,
  • Hamad H. Al Mamari,
  • Hasanain A. A. Almohseni,
  • Younes Fegheh-Hassanpour and
  • David M. Hodgson

Beilstein J. Org. Chem. 2019, 15, 1194–1202, doi:10.3762/bjoc.15.116

Graphical Abstract
  • viability of the rest of sequence outlined in Scheme 2 from an alkylated tartrate. While further CC bond formation by enolate formation at the remaining methine on a monoalkylated tartrate acetonide had been reported by Molander and Harris [29], and by Kelly and co-workers [30]; the question whether such
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Published 31 May 2019

Unexpected polymorphism during a catalyzed mechanochemical Knoevenagel condensation

  • Sebastian Haferkamp,
  • Andrea Paul,
  • Adam A. L. Michalchuk and
  • Franziska Emmerling

Beilstein J. Org. Chem. 2019, 15, 1141–1148, doi:10.3762/bjoc.15.110

Graphical Abstract
  • reaction environment. It was subsequently demonstrated how a combination of different in situ methods can provide more thorough investigation of mechanochemical reaction mechanisms [14][15][16]. Of particular benefit to synthetic reactions, such as CC bond formation [17][18], the use of Raman spectroscopy
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Published 21 May 2019

Electrophilic oligodeoxynucleotide synthesis using dM-Dmoc for amino protection

  • Shahien Shahsavari,
  • Dhananjani N. A. M. Eriyagama,
  • Bhaskar Halami,
  • Vagarshak Begoyan,
  • Marina Tanasova,
  • Jinsen Chen and
  • Shiyue Fang

Beilstein J. Org. Chem. 2019, 15, 1116–1128, doi:10.3762/bjoc.15.108

Graphical Abstract
  • periodate, if the oxidized Dmoc in the linker were unstable, and the 2' and 3'-OH groups were exposed before sodium periodate were removed, the CC bond between the 2' and 3' carbons could be cleaved. With the finding of the relatively high stability of the oxidized Dmoc function, we are more confident that
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Published 20 May 2019

Switchable selectivity in Pd-catalyzed [3 + 2] annulations of γ-oxy-2-cycloalkenones with 3-oxoglutarates: C–C/C–C vs C–C/O–C bond formation

  • Yang Liu,
  • Julie Oble and
  • Giovanni Poli

Beilstein J. Org. Chem. 2019, 15, 1107–1115, doi:10.3762/bjoc.15.107

Graphical Abstract
  • or C–C/O–C annulation at will, thus providing an easy access to annulated cyclopentanic structures III or annulated furan-based motifs IV, respectively. Additionally, in the case of C–C/CC bond forming annulations, the products III can undergo two decarboxylation steps leading to bis-cycloalkanone
  • hour) generated annulated product 4a arising from C-allylation (CC bond forming)/intramolecular O-Michael addition (O–C bond forming) sequence. The purification of the crude reaction was easier using the Pd(OAc)2 and dppb system (Table 1, entry 2), which was thus chosen to continue the optimization
  • transient η2-alkene complex A (steps a and b). Deprotonation of the pro-nucleophile 1a by the counter-anion of the η3-allyl-Pd complex exchanges the benzoate for the enolate anion (step c) [50], and following CC bond formation from the resulting anion-scrambled complex C leads to the Pd(0) complex D (step
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Published 16 May 2019

Novel (2-amino-4-arylimidazolyl)propanoic acids and pyrrolo[1,2-c]imidazoles via the domino reactions of 2-amino-4-arylimidazoles with carbonyl and methylene active compounds

  • Victoria V. Lipson,
  • Tetiana L. Pavlovska,
  • Nataliya V. Svetlichnaya,
  • Anna A. Poryvai,
  • Nikolay Yu. Gorobets,
  • Erik V. Van der Eycken,
  • Irina S. Konovalova,
  • Svetlana V. Shiskina,
  • Alexander V. Borisov,
  • Vladimir I. Musatov and
  • Alexander V. Mazepa

Beilstein J. Org. Chem. 2019, 15, 1032–1045, doi:10.3762/bjoc.15.101

Graphical Abstract
  • CN at 2250 cm−1. In addition, there are characteristic bands at 1664–1668 cm−1, which may include both C=C bond and the exocyclic C=N bond. Fluctuations of endocyclic C=N fragments are observed at 1584 cm−1. Thus, at least one nitrile and one NH2 group are present in the obtained compounds. The 1H
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Published 06 May 2019

Strong hyperconjugative interactions limit solvent and substituent influence on conformational equilibrium: the case of cis-2-halocyclohexylamines

  • Camila B. Francisco,
  • Cleverton S. Fernandes,
  • Ulisses Z. de Melo,
  • Roberto Rittner,
  • Gisele F. Gauze and
  • Ernani A. Basso

Beilstein J. Org. Chem. 2019, 15, 818–829, doi:10.3762/bjoc.15.79

Graphical Abstract
  • equatorial halogen orientation). Previous publications have already reported the C–H bond as slightly better donor than CC bond [34][35]. Therefore, in the sum of interactions existent in the studied systems the hyperconjugation stands out, explaining the axial halogen and equatorial NH2 (ea) preference in
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Published 01 Apr 2019
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