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Search for "amide" in Full Text gives 966 result(s) in Beilstein Journal of Organic Chemistry. Showing first 200.
Copper-promoted C5-selective bromination of 8-aminoquinoline amides with alkyl bromides
- Changdong Shao,
- Chen Ma,
- Li Li,
- Jingyi Liu,
- Yanan Shen,
- Chen Chen,
- Qionglin Yang,
- Tianyi Xu,
- Zhengsong Hu,
- Yuhe Kan and
- Tingting Zhang
Beilstein J. Org. Chem. 2024, 20, 155–161, doi:10.3762/bjoc.20.14
- such as 2d, 2e, and 2f performed well, affording the brominated product 3aa in excellent yields (90–99%). However, transformations of amide 1a to the brominated product 3aa employing unactivated alkyl bromides (2g–i) as reaction partners proceeded with low efficiency (0–53%). Notably, the reactivity of
- aliphatic amide substrates, and proceeds well with activated and unactivated alkyl bromides. Further studies on mechanistic details and the persistent exploration of halogen sources are ongoing in our laboratory. Experimental A 35 mL sealed tube equipped with a stirring bar was charged with 8
Graphical Abstract
Scheme 1: Methods for the C5-selective bromination of 8-aminoquinoline amides.
Scheme 2: Substrate scope of the 8-aminoquinoline amides. Reaction conditions: 1 (0.2 mmol), 2a (0.8 mmol), C...
Scheme 3: Substrate scope of the bromoalkanes. Reaction conditions: 1a (0.2 mmol), 2 (0.8 mmol), Cu(OAc)2·H2O...
Scheme 4: Further substrate scope investigations and gram-scale application.
Scheme 5: Control experiments and proposed mechanism.
Perspectives on push–pull chromophores derived from click-type [2 + 2] cycloaddition–retroelectrocyclization reactions of electron-rich alkynes and electron-deficient alkenes
- Michio Yamada
Beilstein J. Org. Chem. 2024, 20, 125–154, doi:10.3762/bjoc.20.13
- substructures. Consequently, the macrocycle was tethered to the peptide segment through amide–amide hydrogen bonding, and 44 was obtained with 30% yield. The generation of 44 was accompanied by the formation of the corresponding free thread with 62% yield, resulting from the reaction between the thread
Graphical Abstract
Scheme 1: Pathway of the [2 + 2] CA–RE reaction of an electron-rich alkyne with TCNE or TCNQ. EDG = electron-...
Scheme 2: Reaction pathway for DMA-appended acetylene and TCNEO.
Scheme 3: Pathway of the [2 + 2] CA–RE reaction between 1 and DCFs.
Scheme 4: Sequential double [2 + 2] CA–RE reactions between 1 and TCNE.
Scheme 5: Divergent chemical transformation pathways of TCBD 6.
Scheme 6: Synthesis of 12.
Scheme 7: [2 + 2] CA–RE reaction of 1 with 14. TCE = 1,1,2,2-tetrachloroethane.
Scheme 8: Autocatalytic model proposed by Nielsen et al.
Scheme 9: Synthesis of anthracene-embedded TCBD compound 19.
Scheme 10: Sequence of the [2 + 2] CA–RE reaction between dibenzo-fused cyclooctyne or cyclooctadiyne and TCNE...
Scheme 11: [2 + 2] CA–RE reaction between the CPP derivatives and TCNE. THF = tetrahydrofuran.
Scheme 12: [2 + 2] CA–RE reaction between ethynylfullerenes 31 and TCNE and subsequent thermal rearrangement.
Scheme 13: Pathway of the [2 + 2] CA–RE reaction between TCNE and 34, followed by additional skeletal transfor...
Scheme 14: Synthesis scheme for heterocycle 38 from the reaction between TCNE and 1 in water and a surfactant.
Scheme 15: Synthesis scheme of the CDA product 41.
Scheme 16: Synthesis of rotaxanes 44 and 46 via the [2 + 2] CA–RE reaction.
Scheme 17: Synthesis of a CuI bisphenanthroline-based rotaxane 50.
Figure 1: Structures of the chiral push–pull chromophores 51–56.
Figure 2: Structures of the axially chiral TCBD 57 and DCNQ 58 bearing a C60 core.
Figure 3: Structures of the axially chiral SubPc–TCBD–aniline conjugates 59 and 60 and the subporphyrin–TCBD–...
Figure 4: Structures of 63 and the TCBD 64.
Figure 5: Structures of the fluorophore-containing TCBDs 65–67.
Figure 6: Structures of the fluorophore-containing TCBDs 68–72.
Figure 7: Structures of the urea-containing TCBDs 73–75.
Figure 8: Structures of the fullerene–TCBD and DCNQ conjugates 76–79 and their reference compounds 80–83.
Figure 9: Structures of the ZnPc–TCBD–aniline conjugates 84 and 85.
Figure 10: Structures of the ZnP–PCBD and TCBD conjugates 86–88.
Figure 11: Structures of the porphyrin-based donor–acceptor conjugates (89–104).
Figure 12: Structures of the porphyrin–PTZ or DMA conjugates 105–112.
Figure 13: Structures of the BODIPY–Acceptor–TPA or PTZ conjugates 113–116.
Figure 14: Structures of the corrole–TCBD conjugates 117 and 118.
Figure 15: Structure of the dendritic TCBD 119.
Figure 16: Structures of the TCBDs 120–126.
Figure 17: Structures of the precursor 127 and TCBDs 128–130.
Figure 18: Structures of 131–134 utilized for BHJ OSCs.
Visible-light-induced radical cascade cyclization: a catalyst-free synthetic approach to trifluoromethylated heterocycles
- Chuan Yang,
- Wei Shi,
- Jian Tian,
- Lin Guo,
- Yating Zhao and
- Wujiong Xia
Beilstein J. Org. Chem. 2024, 20, 118–124, doi:10.3762/bjoc.20.12
- amine functionalized substrate, because of competition of the reaction site during the synthesis of substrates. However, an amide-substituted indole furnished a clean product without competition; for example, product 3u was derived from melatonin with an amide functional group, whose reaction to the
Graphical Abstract
Figure 1: Representative dihydropyrido[1,2-a]indolone derivatives.
Scheme 1: Selected works for the construction of dihydropyrido[1,2-a]indolones and current methodology.
Scheme 2: Substrate scope of the cascade reaction.
Scheme 3: Radical trapping experiment.
Figure 2: UV–vis spectra of substrates; [1a] 0.33 M, [2a] 0.11 M.
Scheme 4: Plausible reaction mechanism.
Photoinduced in situ generation of DNA-targeting ligands: DNA-binding and DNA-photodamaging properties of benzo[c]quinolizinium ions
- Julika Schlosser,
- Olga Fedorova,
- Yuri Fedorov and
- Heiko Ihmels
Beilstein J. Org. Chem. 2024, 20, 101–117, doi:10.3762/bjoc.20.11
- the amine 2b gave the corresponding amide 2g in 28% yield. The chloro-substituted derivative 2e was synthesized in a Sandmeyer-reaction from 2b in 20% yield. The products 2a–g were identified and fully characterized by NMR spectroscopy (1H, 13C, COSY, HSQC, and HMBC), elemental analyses, and mass
Graphical Abstract
Scheme 1: Photoinduced formation of benzo[c]quinolizinium and its interaction with DNA upon intercalation.
Scheme 2: Synthesis of styrylpyridine derivatives 2a–g. Conditions: i: piperidine, MeOH, reflux (2a,c), ii: C...
Figure 1: Absorption spectra of styrylpyridine derivatives 2a (black), 2b (red), 2c (blue), 2d (green), 2e (m...
Figure 2: Changes of the absorption spectra during the irradiation of 2a in MeCN for 16 min (A), 2b in MeCN f...
Figure 3: Changes of the absorption spectra during the irradiation of 2c for 13 min (A), 2d for 12 min (B), 2e...
Scheme 3: Photoinduced formation of styrylpyridine derivatives 2b–g to the benzo[c]quinolizinium ions 3b–g (y...
Figure 4: Photometric titration of ct DNA to 3c (A) 3e (B) 3f (C) and 3g (D) (c = 20 µM) in Na phosphate buff...
Figure 5: Fluorimetric titration of ct DNA to 3c (A), 3e (B), 3f (C), and 3g (D) (c = 20 µM) in Na phosphate ...
Figure 6: CD (A) and LD (B) spectra of 3f and ct DNA (cDNA = 20 µM) in Na phosphate buffer (pH 7.0, T = 20 °C...
Figure 7: Changes of the absorption (A) and CD (B) spectra during the irradiation of 2e (1) and 2f (2) (c = 2...
Scheme 4: Proposed mechanisms for the photoinduced DNA damage initiated by photoexcitation of benzoquinolizin...
Using the phospha-Michael reaction for making phosphonium phenolate zwitterions
- Matthias R. Steiner,
- Max Schmallegger,
- Larissa Donner,
- Johann A. Hlina,
- Christoph Marschner,
- Judith Baumgartner and
- Christian Slugovc
Beilstein J. Org. Chem. 2024, 20, 41–51, doi:10.3762/bjoc.20.6
- donors attached to the alkyl substituent of the phosphonium center (Figure 3). This hypothesis is further supported by the observation of two very different chemical shifts for the two amide protons in the 1H NMR spectrum of 2b in CDCl3 giving resonance at 5.21 and 8.58 ppm. Kinetic studies In the next
- for the conversion of acrylamide, which is probably disturbed when the hydrogen bond donor solvent methanol is interacting with the amide group and/or the hydroxy group. Conclusion The conjugate addition of 2,4-di-tert-butyl-6-(diphenylphosphino)phenol to Michael acceptor molecules allows for a facile
Graphical Abstract
Scheme 1: Reaction of 1 with various Michael acceptors (EWG = electron-withdrawing group) forming the zwitter...
Figure 1: 1H NMR spectrum of 2a recorded on a 300 MHz spectrometer in CDCl3 at 23 °C; the inset shows a 3D-mo...
Figure 2: a) Molecular structure of 2a, hydrogen atoms omitted for clarity, thermal ellipsoids drawn at 30% p...
Figure 3: Left: UV–vis spectra of 2a, 2b and 2d in chloroform (straight lines) and in methanol (dotted lines)...
Figure 4: Conversion of 1 (initial c = 0.25 mM) toward 2a, 2b, or 2d in the presence of the respective Michae...
Scheme 2: Proposed mechanism for intramolecular proton transfer in zwitterion formation with Michael acceptor...
Synthesis of N-acyl carbazoles, phenoxazines and acridines from cyclic diaryliodonium salts
- Nils Clamor,
- Mattis Damrath,
- Thomas J. Kuczmera,
- Daniel Duvinage and
- Boris J. Nachtsheim
Beilstein J. Org. Chem. 2024, 20, 12–16, doi:10.3762/bjoc.20.2
- equiv amide, 15 mol % CuI, 30 mol % diglyme, 3.00 equiv K2CO3 and 2.00 equiv dibenzo[b,d]iodol-5-ium trifluoromethanesulfonate. Scope of iodanes. aIsolated yields, 200 µmol scale, all reactions carried out in p-xylene, with 1.00 equiv amide 15 mol % CuI, 30 mol % diglyme, 3.00 equiv K2CO3 and 2.00 equiv
Graphical Abstract
Scheme 1: Examples for direct syntheses of N-acyl heteroaromatic compounds.
Scheme 2: Scope of amides. aIsolated yields, 200 µmol scale, all reactions carried out in p-xylene, with 1.00...
Scheme 3: Scope of iodanes. aIsolated yields, 200 µmol scale, all reactions carried out in p-xylene, with 1.0...
Aldiminium and 1,2,3-triazolium dithiocarboxylate zwitterions derived from cyclic (alkyl)(amino) and mesoionic carbenes
- Nedra Touj,
- François Mazars,
- Guillermo Zaragoza and
- Lionel Delaude
Beilstein J. Org. Chem. 2023, 19, 1947–1956, doi:10.3762/bjoc.19.145
- NHC·CS2 zwitterions relies on the deprotonation of an azolium salt with a strong base, typically potassium tert-butoxide or potassium bis(trimethylsilyl)amide (also known as potassium hexamethyldisilazide, KHMDS) followed by the addition of carbon disulfide either in one pot or after the isolation of the
Graphical Abstract
Figure 1: Various types of stable singlet carbenes and their acronyms.
Figure 2: Various types of NHC·CS2 zwitterions and their coordination modes.
Scheme 1: Synthesis of CAAC·CS2 zwitterion 2 from its free carbene parent 1.
Scheme 2: Synthesis of CAAC·CS2 zwitterions 4a–c with KN(SiMe3)2.
Scheme 3: Synthesis of 1,2,3-triazolium iodides 5a–f.
Scheme 4: Synthesis of MIC·CS2 zwitterions 6a and 6b with KN(SiMe3)2.
Scheme 5: Synthesis of MIC·CS2 zwitterions 6c–f with NaOt-Bu.
Figure 3: ORTEP representations of zwitterions 4a (CAAC-Mes-Cy·CS2, top) and 4c (CAAC-Die-MePh·CS2, bottom) w...
Figure 4: ORTEP representations of zwitterions 6b (MIC-Dip-Ph-Me·CS2, top) and 6e (MIC-Mes-Bu-Me·CS2, bottom)...
Anion–π catalysis on carbon allotropes
- M. Ángeles Gutiérrez López,
- Mei-Ling Tan,
- Giacomo Renno,
- Augustina Jozeliūnaitė,
- J. Jonathan Nué-Martinez,
- Javier Lopez-Andarias,
- Naomi Sakai and
- Stefan Matile
Beilstein J. Org. Chem. 2023, 19, 1881–1894, doi:10.3762/bjoc.19.140
- derivatives. In fullerene 8, this is an amide with a short ethylene tether for the tertiary amine (Figure 3). Fullerene 8 catalyzed the formation of the addition product 6 with high selectivity over the decarboxylation product 7 [12]. The experimental product ratio A/D8 was divided by the product ratio A/D9
- control 12, a secondary Bingel amide in 13 caused a drop to A/D13/12 = 1.6. Similarly, low A/D14/12 = 1.5 for an ester in 14 supported that removal of the hydrogen-bond donor in 5 rather than steric constraints account for the decrease in anion–π catalysis. Elongation of the tether in the ester series 14
- –16 was as in the amide series from 8 and thus supported entropic contributions to anion–π catalysis. Steric increase of the secondary amide in 17 impeded anion–π catalysis, presumably because the catalytic π surface next to the ammonium cation became inaccessible for anions paired with the tethered
Graphical Abstract
Figure 1: (A) Anion–π catalysis: Stabilization of anionic transition states from substrate S to product P on ...
Figure 2: Bioinspired enolate addition chemistry to benchmark anion–π catalysts: Stabilization of “enol” inte...
Figure 3: Structure and activity of fullerene-amine dyads to catalyze the intrinsically disfavored but biolog...
Figure 4: Asymmetric anion–π catalysis of intrinsically disfavored exo-selective Diels–Alder reactions on ful...
Figure 5: Asymmetric anion–π catalysis to install remote stereogenic centers on fullerene catalyst 21, with n...
Figure 6: Primary anion–π autocatalysis on monofunctional fullerene 31, with catalytic and autocatalytic rate...
Figure 7: (A) Macrodipoles induced by anionic transition states account for anion–π catalysis on fullerenes. ...
Figure 8: Structure and activity of covalently and non-covalently modified SWCNTs and MWCNTs, with A/D ratios...
Figure 9: (A) Epoxide-opening ether cyclization on pristine carbon nanotubes occurs with (XVI) but not withou...
Figure 10: Electric-field-induced anion–π catalysis on MWCNTs 3 on graphite 76 in electrochemical microfluidic...
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
- corresponding acyl chloride 11 with thionyl chloride. Finally, the cinchona squaramide with linker 7 and the octadecylated gallic acid chloride 11 were coupled to form an amide using triethylamine as a base. The crude product was purified by chromatography and precipitated from acetonitrile to gain the
Graphical Abstract
Figure 1: Application of cinchona squaramide 1 and recyclable, lipophilic cinchona squaramide organocatalysts ...
Scheme 1: Synthesis of demethylated cinchona squaramide organocatalyst and the incorporation of the flexible ...
Scheme 2: Synthesis of the lipophilic tag from methyl gallate (8) and attachment to the cinchona squaramide.
Figure 2: Classification of the tested non-polar solvents according to the GSK’s solvent sustainability guide ...
Figure 3: Recycling of the lipophilic organocatalyst in the stereoselective Michael addition by replacing the...
Scheme 3: A new, stereoselective synthetic route for baclofen.
Scheme 4: Gram-scale synthesis of (S)-baclofen hydrochloride.
Synthetic approach to 2-alkyl-4-quinolones and 2-alkyl-4-quinolone-3-carboxamides based on common β-keto amide precursors
- Yordanka Mollova-Sapundzhieva,
- Plamen Angelov,
- Danail Georgiev and
- Pavel Yanev
Beilstein J. Org. Chem. 2023, 19, 1804–1810, doi:10.3762/bjoc.19.132
- intermediate β-enamino amides 2 are easily available by condensation of the corresponding β-keto amide 1 and an amine (Scheme 1, conditions i). As the amine here plays only an auxiliary role, for the purpose of this research we opted for inexpensive ethylamine. Compounds 2 were obtained by simply stirring a
- dichloromethane solution of the corresponding keto amide 1 with a slight excess of 70% aqueous ethylamine over Na2SO4 and were used directly in the next step, without purification. These compounds are highly reactive at their α-position towards acylating reagents and this provides an opportunity to prepare the
Graphical Abstract
Scheme 1: Preparation of α-(o-nitrobenzoyl)-β-enamino amides 3. Reagents and conditions: i) EtNH2 (70% aq, 1....
Scheme 2: Alternative manipulations of intermediates 3, leading to either 2-alkyl-4-quinolones 8 (via enamino...
Effects of the aldehyde-derived ring substituent on the properties of two new bioinspired trimethoxybenzoylhydrazones: methyl vs nitro groups
- Dayanne Martins,
- Roberta Lamosa,
- Talis Uelisson da Silva,
- Carolina B. P. Ligiero,
- Sérgio de Paula Machado,
- Daphne S. Cukierman and
- Nicolás A. Rey
Beilstein J. Org. Chem. 2023, 19, 1713–1727, doi:10.3762/bjoc.19.125
- around the conjugated amide single bond (N–C=O). N-Acylhydrazones have also gained attention in literature due to other applications, ranging from medicine to supramolecular chemistry [7][8]. Among their applicability is the area of optoelectronic devices, in which they are used for the manufacture of
- only one NH signal around 12 ppm, indicating the presence exclusively of the (E)-isomer in solution. Furthermore, steric hindrance in these cases allow only for the formation of the antiperiplanar conformation around the conjugated amide single bond. Full assignments, with the chemical shifts and
Graphical Abstract
Scheme 1: Structure of (A) 3-methylsalicylaldehyde 3,4,5-trimethoxybenzoyl hydrazone (hdz-CH3) and (B) 3-nitr...
Figure 1: ORTEP representation of the new N-acylhydrazones synthesized in the present work, drawn with therma...
Figure 2: (A) Superposition of molecular structures and stacked motifs of (B) hdz-CH3 and (C) hdz-NO2.
Figure 3: Overlap of the experimental (carbon atoms colored in gray) and theoretical structures (calculated w...
Figure 4: Mid-infrared spectra of the compounds. Experimental conditions: KBr pellets, room temperature. Calc...
Figure 5: 1H NMR (400 MHz) spectra of (A) hdz-CH3 and (B) hdz-NO2 in DMSO-d6 at 25 °C.
Figure 6: Electronic absorption spectra in a selected wavelength region for a solution of hdz-CH3 in 10% DMSO...
Figure 7: Electronic absorption spectra of hdz-NO2 in selected wavelength regions. Experimental conditions: l...
Scheme 2: General scheme for the synthesis of the studied hydrazones.
Synthesis and biological evaluation of Argemone mexicana-inspired antimicrobials
- Jessica Villegas,
- Bryce C. Ball,
- Katelyn M. Shouse,
- Caleb W. VanArragon,
- Ashley N. Wasserman,
- Hannah E. Bhakta,
- Allen G. Oliver,
- Danielle A. Orozco-Nunnelly and
- Jeffrey M. Pruet
Beilstein J. Org. Chem. 2023, 19, 1511–1524, doi:10.3762/bjoc.19.108
- through the use of additional NaOH and refluxing the crude alkylation mixture. After heating for 3 h, the desired intermediates were recovered in acceptable yields over this two-step one-pot sequence. The amide hydrolysis of 7 and 8 to the desired free naphthylamines 9 and 10 proved challenging, but was
- nevertheless successful, albeit in low yields after an extended reaction time. We explored KOH and NH3 as alternatives to NaOH for this amide cleavage, and found the resulting yields less satisfactory. We also explored the amide hydrolysis under acidic conditions as well, though this resulted to almost
Graphical Abstract
Figure 1: Zones of inhibition for 1 mg of evaporated methanolic (MeOH) extracts from various parts of the A. ...
Scheme 1: General route to berberine variants, displaying the numbering system for the berberine ring.
Scheme 2: Synthesis of new berberine variants. Reductive amination to a secondary amine was followed by cycli...
Figure 2: X-ray crystal structures of the oxidation byproducts a) B4 (CCDC 2271457) and b) B6 (CCDC 2271458; ...
Scheme 3: Direct modification of the original berberine structure.
Scheme 4: Preparation of non-cyclic charged variants of B1.
Scheme 5: Partial reduction of compound B1 to B14.
Figure 3: Kirby–Bauer zones of inhibition for all variants B1–B14 compared to original berberine (B). Mean zo...
Scheme 6: Synthesis of the substituted 2-bromoaminonaphthalenes 9 and 10.
Scheme 7: Completion of the synthesis of variants C1–C4.
Figure 4: Kirby–Bauer zones of inhibition for variants C1–C4 compared to original chelerythrine (C). Mean zon...
Figure 5: Effects of original berberine and all variants against T84 human colon cancer cells. Cells were tre...
Figure 6: Effects of original chelerythrine and all variants against T84 human colon cancer. Cells were treat...
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
- with N-(arylthio)phthalimide 14 and N-chlorophthalimide (96) under phase-transfer conditions was developed by Maruoka and co-workers (Scheme 39) [74]. The presence of chiral bifunctional catalysts C and D with the amide, or sulfonamide moieties could improve the enantioselectivity. Also, the
- oxychalcogenation of o‑vinylanilides with N‑(arylthio/arylseleno)succinimides. Lewis base/Brønsted acid dual-catalytic C–H sulfenylation of aryls. Lewis base-catalyzed sulfenoamidation of alkenes. Cyclization of allylic amide using a Brønsted acid and tetrabutylammonium chloride. Catalytic electrophilic
Graphical Abstract
Scheme 1: Sulfur-containing bioactive molecules.
Scheme 2: Scandium-catalyzed synthesis of thiosulfonates.
Scheme 3: Palladium-catalyzed aryl(alkyl)thiolation of unactivated arenes.
Scheme 4: Catalytic cycle for Pd-catalyzed aryl(alkyl)thiolation of unactivated arenes.
Scheme 5: Iron- or boron-catalyzed C–H arylthiation of substituted phenols.
Scheme 6: Iron-catalyzed azidoalkylthiation of alkenes.
Scheme 7: Plausible mechanism for iron-catalyzed azidoalkylthiation of alkenes.
Scheme 8: BF3·Et2O‑mediated electrophilic cyclization of aryl alkynoates.
Scheme 9: Tentative mechanism for BF3·Et2O‑mediated electrophilic cyclization of aryl alkynoates.
Scheme 10: Construction of 6-substituted benzo[b]thiophenes.
Scheme 11: Plausible mechanism for construction of 6-substituted benzo[b]thiophenes.
Scheme 12: AlCl3‑catalyzed cyclization of N‑arylpropynamides with N‑sulfanylsuccinimides.
Scheme 13: Synthetic utility of AlCl3‑catalyzed cyclization of N‑arylpropynamides with N‑sulfanylsuccinimides.
Scheme 14: Sulfenoamination of alkenes with sulfonamides and N-sulfanylsuccinimides.
Scheme 15: Lewis acid/Brønsted acid controlled Pd-catalyzed functionalization of aryl C(sp2)–H bonds.
Scheme 16: Possible mechanism for Lewis acid/Brønsted acid controlled Pd-catalyzed functionalization of aryl C...
Scheme 17: FeCl3-catalyzed carbosulfenylation of unactivated alkenes.
Scheme 18: Copper-catalyzed electrophilic thiolation of organozinc halides.
Scheme 19: h-BN@Copper(II) nanomaterial catalyzed cross-coupling reaction of sulfoximines and N‑(arylthio)succ...
Scheme 20: AlCl3‑mediated cyclization and sulfenylation of 2‑alkyn-1-one O‑methyloximes.
Scheme 21: Lewis acid-promoted 2-substituted cyclopropane 1,1-dicarboxylates with sulfonamides and N-(arylthio...
Scheme 22: Lewis acid-mediated cyclization of β,γ-unsaturated oximes and hydrazones with N-(arylthio/seleno)su...
Scheme 23: Credible pathway for Lewis acid-mediated cyclization of β,γ-unsaturated oximes with N-(arylthio)suc...
Scheme 24: Synthesis of 4-chalcogenyl pyrazoles via chalcogenation/cyclization of α,β-alkynic hydrazones.
Scheme 25: Controllable synthesis of 3-thiolated pyrroles and pyrrolines.
Scheme 26: Possible mechanism for controllable synthesis of 3-thiolated pyrroles and pyrrolines.
Scheme 27: Co-catalyzed C2-sulfenylation and C2,C3-disulfenylation of indole derivatives.
Scheme 28: Plausible catalytic cycle for Co-catalyzed C2-sulfenylation and C2,C3-disulfenylation of indoles.
Scheme 29: C–H thioarylation of electron-rich arenes by iron(III) triflimide catalysis.
Scheme 30: Difunctionalization of alkynyl bromides with thiosulfonates and N-arylthio succinimides.·
Scheme 31: Suggested mechanism for difunctionalization of alkynyl bromides with thiosulfonates and N-arylthio ...
Scheme 32: Synthesis of thioesters, acyl disulfides, ketones, and amides by N-thiohydroxy succinimide esters.
Scheme 33: Proposed mechanism for metal-catalyzed selective acylation and acylthiolation.
Scheme 34: AlCl3-catalyzed synthesis of 3,4-bisthiolated pyrroles.
Scheme 35: α-Sulfenylation of aldehydes and ketones.
Scheme 36: Acid-catalyzed sulfetherification of unsaturated alcohols.
Scheme 37: Enantioselective sulfenylation of β-keto phosphonates.
Scheme 38: Organocatalyzed sulfenylation of 3‑substituted oxindoles.
Scheme 39: Sulfenylation and chlorination of β-ketoesters.
Scheme 40: Intramolecular sulfenoamination of olefins.
Scheme 41: Plausible mechanism for intramolecular sulfenoamination of olefins.
Scheme 42: α-Sulfenylation of 5H-oxazol-4-ones.
Scheme 43: Metal-free C–H sulfenylation of electron-rich arenes.
Scheme 44: TFA-promoted C–H sulfenylation indoles.
Scheme 45: Proposed mechanism for TFA-promoted C–H sulfenylation indoles.
Scheme 46: Organocatalyzed sulfenylation and selenenylation of 3-pyrrolyloxindoles.
Scheme 47: Organocatalyzed sulfenylation of S-based nucleophiles.
Scheme 48: Conjugate Lewis base Brønsted acid-catalyzed sulfenylation of N-heterocycles.
Scheme 49: Mechanism for activation of N-sulfanylsuccinimide by conjugate Lewis base Brønsted acid catalyst.
Scheme 50: Sulfenylation of deconjugated butyrolactams.
Scheme 51: Intramolecular sulfenofunctionalization of alkenes with phenols.
Scheme 52: Organocatalytic 1,3-difunctionalizations of Morita–Baylis–Hillman carbonates.
Scheme 53: Organocatalytic sulfenylation of β‑naphthols.
Scheme 54: Acid-promoted oxychalcogenation of o‑vinylanilides with N‑(arylthio/arylseleno)succinimides.
Scheme 55: Lewis base/Brønsted acid dual-catalytic C–H sulfenylation of aryls.
Scheme 56: Lewis base-catalyzed sulfenoamidation of alkenes.
Scheme 57: Cyclization of allylic amide using a Brønsted acid and tetrabutylammonium chloride.
Scheme 58: Catalytic electrophilic thiocarbocyclization of allenes with N-thiosuccinimides.
Scheme 59: Suggested mechanism for electrophilic thiocarbocyclization of allenes with N-thiosuccinimides.
Scheme 60: Chiral chalcogenide-catalyzed enantioselective hydrothiolation of alkenes.
Scheme 61: Proposed mechanism for chalcogenide-catalyzed enantioselective hydrothiolation of alkenes.
Scheme 62: Organocatalytic sulfenylation for synthesis a diheteroatom-bearing tetrasubstituted carbon centre.
Scheme 63: Thiolative cyclization of yne-ynamides.
Scheme 64: Synthesis of alkynyl and acyl disulfides from reaction of thiols with N-alkynylthio phthalimides.
Scheme 65: Oxysulfenylation of alkenes with 1-(arylthio)pyrrolidine-2,5-diones and alcohols.
Scheme 66: Arylthiolation of arylamines with (arylthio)-pyrrolidine-2,5-diones.
Scheme 67: Catalyst-free isothiocyanatoalkylthiation of styrenes.
Scheme 68: Sulfenylation of (E)-β-chlorovinyl ketones toward 3,4-dimercaptofurans.
Scheme 69: HCl-promoted intermolecular 1, 2-thiofunctionalization of aromatic alkenes.
Scheme 70: Possible mechanism for HCl-promoted 1,2-thiofunctionalization of aromatic alkenes.
Scheme 71: Coupling reaction of diazo compounds with N-sulfenylsuccinimides.
Scheme 72: Multicomponent reactions of disulfides with isocyanides and other nucleophiles.
Scheme 73: α-Sulfenylation and β-sulfenylation of α,β-unsaturated carbonyl compounds.
Application of N-heterocyclic carbene–Cu(I) complexes as catalysts in organic synthesis: a review
- Nosheen Beig,
- Varsha Goyal and
- Raj K. Bansal
Beilstein J. Org. Chem. 2023, 19, 1408–1442, doi:10.3762/bjoc.19.102
- –Cu(I) complexes 12 (Scheme 5). A variety of bases, namely metal alkoxides, alkali metal carbonates, n-butyllithium, and lithium bis(trimethylsilyl)amide have been employed for this purpose. In 2010, Diez-González et al. synthesized a variety of NHC–Cu(I) complexes 14 from imidazolium salts 13 using
Graphical Abstract
Scheme 1: In situ generation of imidazolylidene carbene.
Scheme 2: Hg(II) complex of NHC.
Scheme 3: Isolable and bottlable carbene reported by Arduengo [3].
Scheme 4: First air-stable carbene synthesized by Arduengo in 1992 [5].
Figure 1: General structure of an NHC.
Figure 2: Stabilization of an NHC by donation of the lone pair electrons into the vacant p-orbital (LUMO) at ...
Figure 3: Abnormal NHC reported by Bertrand [8,9].
Figure 4: Cu(d) orbital to σ*C-N(NHC) interactions in NHC–CuX complexes computed at the B3LYP/def2-SVP level ...
Figure 5: Molecular orbital contributions to the NHC–metal bond.
Scheme 5: Synthesis of NHC–Cu(I) complexes by deprotonation of NHC precursors with a base.
Scheme 6: Synthesis of [NHC–CuX] complexes.
Scheme 7: Synthesis of [(ICy)CuX] and [(It-Bu)CuX] complexes.
Scheme 8: Synthesis of iodido-bridged copper–NHC complexes by deprotonation of benzimidazolium salts reported...
Scheme 9: Synthesis of copper complexes by deprotonation of triazolium salts.
Scheme 10: Synthesis of thiazolylidene–Cu(I) complex by deprotonation with KOt-Bu.
Scheme 11: Preparation of NHC–Cu(I) complexes.
Scheme 12: Synthesis of methylmalonic acid-derived anionic [(26a,b)CuCl]Li(THF)2 and zwitterionic (28) heterol...
Scheme 13: Synthesis of diaminocarbene and diamidocarbene (DAC)–Cu(I) complexes.
Scheme 14: Synthesis of the cationic (NHC)2Cu(I) complex 39 from benzimidazolium salts 38 with tetrakis(aceton...
Scheme 15: Synthesis of NHC and ADC (acyclic diamino carbenes) Cu(I) hexamethyldisilazide complexes reported b...
Scheme 16: Synthesis of NHC–copper(I) complexes using an acetylacetonate-functionalized imidazolium zwitterion...
Scheme 17: Synthesis of NHC–Cu(I) complexes through deprotonation of azolium salts with Cu2O.
Scheme 18: Synthesis of NHC–CuBr complex through deprotonation with Cu2O reported by Kolychev [31].
Scheme 19: Synthesis of chiral NHC–CuBr complexes from phenoxyimine-imidazolium salts reported by Douthwaite a...
Scheme 20: Preparation of linear neutral NHC–CuCl complexes through the use of Cu2O. For abbreviations, please...
Scheme 21: Synthesis of abnormal-NHC–copper(I) complexes by Bertrand, Cazin and co-workers [35].
Scheme 22: Microwave-assisted synthesis of thiazolylidene/benzothiazolylidene–CuBr complexes by Bansal and co-...
Scheme 23: Synthesis of NHC–CuX complexes through transmetallation.
Scheme 24: Preparation of six- or seven-membered NHC–Cu(I) complexes through transmetalation from Ag(I) comple...
Scheme 25: Synthesis of 1,2,3-triazolylidene–CuCl complexes through transmetallation of Ag(I) complexes genera...
Scheme 26: Synthesis of NHC–copper complexes having both Cu(I) and Cu(II) units through transmetalation report...
Scheme 27: Synthesis of new [(IPr(CH2)3Si(OiPr)3)CuX] complexes and anchoring on MCM-41.
Scheme 28: Synthesis of bis(trimethylsilyl)phosphide–Cu(I)–NHC complexes through ligand displacement.
Scheme 29: Synthesis of silyl- and stannyl [(NHC)Cu−ER3] complexes.
Scheme 30: Synthesis of amido-, phenolato-, thiophenolato–Cu(NHC) complexes.
Scheme 31: Synthesis of first isolable NHC–Cu–difluoromethyl complexes reported by Sanford et al. [44].
Scheme 32: Synthesis of NHC–Cu(I)–bifluoride complexes reported by Riant, Leyssens and co-workers [45].
Scheme 33: Conjugate addition of Et2Zn to enones catalyzed by an NHC–Cu(I) complex reported by Woodward in 200...
Scheme 34: Hydrosilylation of a carbonyl group.
Scheme 35: NHC–Cu(I)-catalyzed hydrosilylation of ketones reported by Nolan et al. [48,49].
Scheme 36: Application of chiral NHC–CuCl complex 104 for the enantioselective hydrosilylation of ketones.
Scheme 37: Hydrosilylation reactions catalyzed by NHC–Cu(Ot-Bu) complexes.
Scheme 38: NHC–CuCl catalyzed carbonylative silylation of alkyl halides.
Scheme 39: Nucleophilic conjugate addition to an activated C=C bond.
Figure 6: Molecular electrostatic potential maps (MESP) of two NHC–CuX complexes computed at the B3LYP/def2-S...
Scheme 40: Conjugate addition of Grignard reagents to 3-alkyl-substituted cyclohexenones catalyzed by a chiral...
Scheme 41: NHC–copper complex-catalyzed conjugate addition of Grignard reagent to 3-substituted hexenone repor...
Scheme 42: Conjugate addition or organoaluminum reagents to β-substituted cyclic enones.
Scheme 43: Conjugate addition of boronates to acyclic α,β-unsaturated carboxylic esters, ketones, and thioeste...
Scheme 44: NHC–Cu(I)-catalyzed hydroboration of an allene reported by Hoveyda [63].
Scheme 45: Conjugate addition of Et2Zn to cyclohexenone catalyzed by NHC–Cu(I) complex derived from benzimidaz...
Scheme 46: Asymmetric conjugate addition of diethylzinc to 3-nonen-2-one catalyzed by NHC–Cu complexes derived...
Scheme 47: General scheme of a [3 + 2] cycloaddition reaction.
Scheme 48: [3 + 2] Cycloaddition of azides with alkynes catalyzed by NHC–Cu(I) complexes reported by Diez-Gonz...
Scheme 49: Application of NHC–CuCl/N-donor combination to catalyze the [3 + 2] cycloaddition of benzyl azide w...
Scheme 50: [3 + 2] Cycloaddition of azides with acetylenes catalyzed by bis(NHC)–Cu complex 131 and mixed NHC–...
Figure 7: NHC–CuCl complex 133 as catalyst for the [3 + 2] cycloaddition of alkynes with azides at room tempe...
Scheme 51: [3 + 2] Cycloaddition of a bulky azide with an alkynylpyridine using [(NHC)Cu(μ-I)2Cu(NHC)] copper ...
Scheme 52: [3 + 2] Cycloaddition of benzyl azide with phenylacetylene under homogeneous and heterogeneous cata...
Scheme 53: [3 + 2] Cycloaddition of benzyl azide with acetylenes catalyzed by bisthiazolylidene dicopper(I) co...
Figure 8: Copper (I)–NHC linear coordination polymer 137 and its conversion into tetranuclear (138) and dinuc...
Scheme 54: An A3 reaction.
Scheme 55: Synthesis of SiO2-immobilized NHC–Cu(I) catalyst 141 and its application in the A3-coupling reactio...
Scheme 56: Preparation of dual-purpose Ru@SiO2–[(NHC)CuCl] catalyst system 142 developed by Bordet, Leitner an...
Scheme 57: Application of the catalyst system Ru@SiO2–[Cu(NHC)] 142 to the one-pot tandem A3 reaction and hydr...
Scheme 58: A3 reaction of phenylacetylene with secondary amines and aldehydes catalyzed by benzothiazolylidene...
Figure 9: Kohn–Sham HOMOs of phenylacetylene and NHC–Cu(I)–phenylacetylene complex computed at the B3LYP/def2...
Figure 10: Energies of the FMOs of phenylacetylene, iminium ion, and NHC–Cu(I)–phenylacetylene complex compute...
Scheme 59: NHC–Cu(I) catalyzed diboration of ketones 147 by reacting with bis(pinacolato)diboron (148) reporte...
Scheme 60: Protoboration of terminal allenes catalyzed by NHC–Cu(I) complexes reported by Hoveyda and co-worke...
Scheme 61: NHC–CuCl-catalyzed borylation of α-alkoxyallenes to give 2-boryl-1,3-butadienes.
Scheme 62: Regioselective hydroborylation of propargylic alcohols and ethers catalyzed by NHC–CuCl complexes 1...
Scheme 63: NHC–CuOt-Bu-catalyzed semihydrogenation and hydroborylation of alkynes.
Scheme 64: Enantioselective NHC–Cu(I)-catalyzed hydroborations of 1,1-disubstituted aryl olefins reported by H...
Scheme 65: Enantioselective NHC–Cu(I)-catalyzed hydroboration of exocyclic 1,1-disubstituted alkenes reported ...
Scheme 66: Markovnikov-selective NHC–CuOH-catalyzed hydroboration of alkenes and alkynes reported by Jones et ...
Scheme 67: Dehydrogenative borylation and silylation of styrenes catalyzed by NHC–CuOt-Bu complexes developed ...
Scheme 68: N–H/C(sp2)–H carboxylation catalyzed by NHC–CuOH complexes.
Scheme 69: C–H Carboxylation of benzoxazole and benzothiazole derivatives with CO2 using a 1,2,3-triazol-5-yli...
Scheme 70: Use of Cu(I) complex derived from diethylene glycol-functionalized imidazo[1,5,a] pyridin-3-ylidene...
Scheme 71: Allylation and alkenylation of polyfluoroarenes and heteroarenes catalyzed by NHC–Cu(I) complexes r...
Scheme 72: Enantioselective C(sp2)–H allylation of (benz)oxazoles and benzothiazoles with γ,γ-disubstituted pr...
Scheme 73: C(sp2)–H arylation of arenes catalyzed by dual NHC–Cu/NHC–Pd catalytic system.
Scheme 74: C(sp2)–H Amidation of (hetero)arenes with N-chlorocarbamates/N-chloro-N-sodiocarbamates catalyzed b...
Scheme 75: NHC–CuI catalyzed thiolation of benzothiazoles and benzoxazoles.
One-pot nucleophilic substitution–double click reactions of biazides leading to functionalized bis(1,2,3-triazole) derivatives
- Hans-Ulrich Reissig and
- Fei Yu
Beilstein J. Org. Chem. 2023, 19, 1399–1407, doi:10.3762/bjoc.19.101
- converted into several multivalent compounds B by amine or amide bond formations [44][45][46][47]. The transformation of the corresponding azidopyrans and azidooxepanes C or E into multivalent 1,2,3-triazole derivatives D and F by Meldal–Sharpless cycloadditions with suitable alkynes proceeded generally in
Graphical Abstract
Scheme 1: Earlier approaches to multivalent carbohydrate mimetics B, D or F based on enantiopure aminopyran a...
Scheme 2: Synthesis of model compound 3 under conventional conditions and as a one-pot process employing benz...
Scheme 3: One-pot reaction employing enantiopure alkynyl-substituted 1,2-oxazin-4-one derivative 6 leading to...
Scheme 4: One-pot reactions of dihalides 8 and 11 with sodium azide and alkyne 2 leading to symmetric divalen...
Scheme 5: One-pot reactions employing enantiopure alkynyl-substituted 1,2-oxazin-4-one derivative 6 leading t...
Scheme 6: One-pot reaction employing enantiopure alkynyl-substituted 1,2-oxazin-4-ol derivative 19 leading to...
Scheme 7: Reductive ring-openings of 1,2-oxazine derivatives 19 and 23 as simple model compounds by hydrogeno...
Scheme 8: Attempted reductive ring-openings of compound 21 by hydrogenolysis or by samarium diiodide leading ...
Synthesis of ether lipids: natural compounds and analogues
- Marco Antônio G. B. Gomes,
- Alicia Bauduin,
- Chloé Le Roux,
- Romain Fouinneteau,
- Wilfried Berthe,
- Mathieu Berchel,
- Hélène Couthon and
- Paul-Alain Jaffrès
Beilstein J. Org. Chem. 2023, 19, 1299–1369, doi:10.3762/bjoc.19.96
- ] but to the best of our knowledge, R. Berchtold reported in 1982 the first synthesis in large quantities with a control of the chirality at the sn-2 position (Figure 21) [116]. The synthesis starts from (S)-1,2-isopropylideneglycerol (21.1). The deprotonation of the primary alcohol with sodium amide
Graphical Abstract
Figure 1: Chemical structure of some natural ether lipids (ELs).
Figure 2: Synthesis of lyso-PAF and PAF from 1-O-alkylglycerol [64].
Figure 3: Synthesis of lyso-PAF from 1,3-benzylideneglycerol 3.1 [69].
Figure 4: A) Synthesis of the two enantiomers of octadecylglycerol (4.6 and 4.10) from ᴅ-mannitol (4.1); B) s...
Figure 5: Four-step synthesis of PAF 5.6 from (S)-glycidol [73].
Figure 6: Synthesis of 1-O-alkylglycerol A) from solketal, B) from ᴅ- or ʟ-tartaric acid and the intermediate ...
Figure 7: Synthesis of EL building blocks starting from substituted glycidol 7.1a–c [82].
Figure 8: Synthesis of PAF 8.5 by using phosphoramidite 8.2 [86].
Figure 9: Synthesis of oleyl-PAF 9.7 from ʟ-serine [88].
Figure 10: Synthesis of racemic analogues of lyso-PAF 10.8 and PAF 10.9 featuring a phenyl group between the g...
Figure 11: Synthesis of racemic deoxy-lyso-PAF 11.7 and deoxy-PAF 11.8 [91].
Figure 12: Synthesis of racemic thio-PAF 12.8 [93].
Figure 13: Racemic synthesis of 13.6 to illustrate the modification of the glycerol backbone by adding a methy...
Figure 14: Racemic synthesis of 14.5 as an illustration of the introduction of methyl substituents on the glyc...
Figure 15: Synthesis of functionalized sn-2-acyl chains of PC-EL; A) Steglich esterification or acylation reac...
Figure 16: Synthesis of racemic mc-PAF (16.3), a carbamate analogue of PAF [102].
Figure 17: A) Synthesis of (R)-17.2 and (S)-17.6 starting from (S)-solketal (17.1); B) synthesis of N3-PAF (17...
Figure 18: Modification of the phosphocholine polar head to produce PAF analogues [81].
Figure 19: Racemic PAF analogues 19.3 and 19.5 characterized by the absence of the phosphate group [107].
Figure 20: Synthesis of PIP3-PAF (20.7) [108].
Figure 21: Large-scale synthesis of C18-edelfosine (21.8) [116].
Figure 22: Synthesis of C16-edelfosine (22.10) starting from isopropylidene-ʟ-glyceric acid methyl ester (22.1...
Figure 23: Phosphocholine moiety installation by the use of chlorophosphite 23.2 as key reagent [119].
Figure 24: Synthesis of rac-1-alkyl-2-O-methylglycerol (AMG) [120].
Figure 25: Synthesis of stereocontrolled 1-alkyl-2-O-methyl glycerol 25.9 (AMG) from dimethyl ᴅ-tartrate [81].
Figure 26: A) Racemic synthesis of thioether 26.4 [129,130], B) structure of sulfone analogue 26.5 [129].
Figure 27: Stereocontrolled synthesis of C18-edelfosine thioether analogue 27.8 [118].
Figure 28: Synthesis of thioether 28.4 that include a thiophosphate function [134].
Figure 29: Synthesis of ammonium thioether 29.4 and 29.6 [135].
Figure 30: Synthesis of the N-methylamino analogue of edelfosine 30.6 (BN52211) [138].
Figure 31: Synthesis of 1-desoxy analogues of edelfosine; A) with a saturated alkyl chain; B) synthesis of the...
Figure 32: Stereocontrolled synthesis of edelfosine analogue (S)-32.8 featuring a C18:1 lipid chain [142].
Figure 33: Synthesis of edelfosine analogues with modulation of the lipid chain; A) illustration with the synt...
Figure 34: Synthesis of phospholipid featuring a carbamate function to link the lipid chain to the glycerol un...
Figure 35: Synthesis of sesquiterpene conjugates of phospho glycero ether lipids [148].
Figure 36: Racemic synthesis of methyl-substituted glycerol analogues 36.7 and 36.10: A) synthesis of diether ...
Figure 37: Racemic synthesis of ilmofosine (37.6) [155,156].
Figure 38: A) Stereoselective synthesis of 38.5 via a stereoselective hydroboration reaction; B) synthesis of ...
Figure 39: Racemic synthesis of SRI62-834 (39.6) featuring a spiro-tetrahydrofurane heterocycle in position 2 ...
Figure 40: Racemic synthesis of edelfosine analogue 40.5 featuring an imidazole moiety in sn-2 position [160].
Figure 41: Racemic synthesis of fluorine-functionalized EL: A) Synthesis of 41.6 and B) synthesis of 41.8 [161-163].
Figure 42: A) Synthesis of the β-keto-ester 42.6 that also features a decyl linker between the phosphate and t...
Figure 43: Synthesis of phosphonate-based ether lipids; A) edelfosine phosphonate analogue 43.7 and B) thioeth...
Figure 44: Enantioselective synthesis of phosphonates 44.3 and 44.4 [171].
Figure 45: Racemic synthesis of phosphinate-based ether lipid 45.10 [172].
Figure 46: Racemic synthesis of edelfosine arsonium analogue 46.5 [173].
Figure 47: Synthesis of edelfosine dimethylammonium analogue 47.2 [118].
Figure 48: Synthesis of rac-C18-edelfosine methylammonium analogue 48.4 [176].
Figure 49: A) Synthesis of edelfosine N-methylpyrrolidinium analogue 49.2 or N-methylmorpholinium analogue 49.3...
Figure 50: A) Synthesis of edelfosine’s analogue 50.4 with a PE polar group; B) illustration of a pyridinium d...
Figure 51: A) Synthesis of 51.4 featuring a thiazolium cationic moiety; B) synthesis of thiazolium-based EL 51...
Figure 52: Synthesis of cationic ether lipids 52.3, 52.4 and 52.6 [135,183].
Figure 53: Synthesis of cationic carbamate ether lipid 53.5 [184].
Figure 54: Synthesis of cationic sulfonamide 54.5 [185].
Figure 55: Chemical structure of ONO-6240 (55.1) and SRI-63-119 (55.2).
Figure 56: Synthesis of non-ionic ether lipids 56.2–56.9 [188].
Figure 57: Synthesis of ether lipid conjugated to foscarnet 57.6 [189].
Figure 58: A) Synthesis of ether lipid conjugated to arabinofuranosylcytosine; B) synthesis of AZT conjugated ...
Figure 59: Synthesis of quercetin conjugate to edelfosine [191].
Figure 60: Synthesis of 60.8 (Glc-PAF) [194].
Figure 61: A) Synthesis of amino ether lipid 61.7 functionalized with a rhamnose unit and its amide analogue 6...
Figure 62: A) Synthesis of glucose ether lipid 62.4; B) structure of ether lipid 62.5 possessing a maltose uni...
Figure 63: A) Synthesis of glucuronic methyl ester 63.8; B) structure of cellobiose 63.9 and maltose 63.10 ana...
Figure 64: A) Synthesis of maltosyl glycerolipid 64.7; B) structure of lactose analogue 64.8 prepared followin...
Figure 65: A) Asymmetric synthesis of the aglycone moiety starting from allyl 4-methoxyphenyl ether; B) glycos...
Figure 66: A) Synthesis of ohmline possessing a lactose moiety. B) Structure of other glyco glycero lipids pre...
Figure 67: A) Synthesis of lactose-glycerol ether lipid 67.5; B) analogues possessing a maltose (67.6) or meli...
Figure 68: Synthesis of digalactosyl EL 68.6, A) by using trityl, benzyl and acetyl protecting groups, B) by u...
Figure 69: A) Synthesis of α-ohmline; B) structure of disaccharide ether lipids prepared by using similar meth...
Figure 70: Synthesis of lactose ether lipid 70.3 and its analogue 70.6 featuring a carbamate function as linke...
Figure 71: Synthesis of rhamnopyranoside diether 71.4 [196].
Figure 72: Synthesis of 1-O-hexadecyl-2-O-methyl-3-S-(α-ᴅ-1'-thioglucopyranosyl)-sn-glycerol (72.5) [225].
Figure 73: A) Preparation of lipid intermediate 73.4; B) synthesis of 2-desoxy-C-glycoside 73.10 [226].
Figure 74: Synthesis of galactose-pyridinium salt 74.3 [228].
Figure 75: Synthesis of myo-inositol derivative Ino-C2-PAF (75.10) [230].
Figure 76: A) Synthesis of myo-inositol phosphate building block 76.7; B) synthesis of myo-inositolphosphate d...
Figure 77: A) Synthesis of phosphatidyl-3-desoxy-inositol 77.4; B) synthesis of phosphono-3-desoxyinositol 77.9...
Figure 78: A) Structure of diether phosphatidyl-myo-inositol-3,4-diphosphate 78.1; B) synthesis of phosphatidy...
Figure 79: A) Synthesis of diether-phosphatidyl derivative 79.4 featuring a hydroxymethyl group in place of a ...
Figure 80: Synthesis of Glc-amine-PAF [78].
Figure 81: Synthesis of glucosamine ether lipid 81.4 and its analogues functionalized in position 3 of the ami...
Figure 82: Synthesis of fully deprotected aminoglucoside ether lipid 82.5 [246].
Figure 83: Synthesis of C-aminoglycoside 83.12 using Ramberg–Bäcklund rearrangement as a key step [250].
Figure 84: A) List of the most important glyco lipids and amino glyco lipids included in the study of Arthur a...
Figure 85: Synthesis of mannosamine ether lipid 85.6 [254].
Figure 86: A) Synthesis of glucosamine ether lipids with a non-natural ʟ-glucosamine moiety; B) synthesis of e...
Figure 87: A) Structure of the most efficient anticancer agents 87.1–87.4 featuring a diamino glyco ether lipi...
Figure 88: A) Synthesis of diamino glyco ether lipid 87.4; B) synthesis of bis-glycosylated ether lipid 88.10 [256]....
Figure 89: Synthesis of triamino ether lipid 89.4 [260].
Figure 90: Synthesis of chlorambucil conjugate 90.7 [261].
Figure 91: Three main methods for the preparation of glycerol ether lipid 91.3; A) from solketal and via a tri...
Figure 92: Four different methods for the installation of the phosphocholine polar head group; A) method using...
Figure 93: Illustration of two methods for the installation of saccharides or aminosaccharides; A) O-glycosyla...
Organic thermally activated delayed fluorescence material with strained benzoguanidine donor
- Alexander C. Brannan,
- Elvie F. P. Beaumont,
- Nguyen Le Phuoc,
- George F. S. Whitehead,
- Mikko Linnolahti and
- Alexander S. Romanov
Beilstein J. Org. Chem. 2023, 19, 1289–1298, doi:10.3762/bjoc.19.95
- 1. Benzoguanidine has an extended π-conjugation compared with carbazole and is more nitrogen-rich (three N-atoms vs one in carbazole). Thompson et al. recently reported a series of carbene–metal–amide (CMA) (metal = Cu, Ag, Au) emitters employing a benzoguanidine ligand [10]. The extended π
Graphical Abstract
Figure 1: The molecular structures of the title compound 4BGIPN and the benchmark TADF emitter 4CzIPN.
Figure 2: Crystal structure for compound 4BGIPN in monoclinic form ((a) top view and (b) side view) where bla...
Figure 3: Full range cyclic voltammogram for 4BGIPN. Recorded using a glassy carbon electrode in THF solution...
Figure 4: UV–vis absorption spectra for compound 4BGIPN in various solvents.
Figure 5: Photoluminescence spectra for 4BGIPN at 295 and 77 K in (top left) MCH solution; (bottom left) Zeon...
Figure 6: Energy state diagram and natural transition orbitals HONTO and LUNTO for compound 4BGIPN in excited...
Non-noble metal-catalyzed cross-dehydrogenation coupling (CDC) involving ether α-C(sp3)–H to construct C–C bonds
- Hui Yu and
- Feng Xu
Beilstein J. Org. Chem. 2023, 19, 1259–1288, doi:10.3762/bjoc.19.94
- . (Scheme 34) [99]. The CDC reaction was initiated by a radical oxidative addition of C(sp2)–H and the final product was obtained by amide hydrolysis. The strategy provides a simple and practical method for synthesizing β-oxoketones. In 2015, Cai et al. reported a novel CDC of C(sp3)–H and C(sp2)–H bonds in
Graphical Abstract
Scheme 1: Research progress of coupling reactions and active compounds containing α-C(sp3)-functionalized eth...
Scheme 2: Transition-metal-catalyzed CDC pathways.
Scheme 3: CDC of active methylene compounds in the α-C(sp3) position of ethers.
Scheme 4: InCl3/Cu(OTf)2/NHPI co-catalyzed CDC reaction.
Scheme 5: CDC of cyclic benzyl ethers with aldehydes.
Scheme 6: Cu-catalyzed CDC of (a) unactivated C(sp3)–H ethers with simple ketones and (b) double C(sp3)−H fun...
Scheme 7: Cu-catalyzed CDC of C(sp3)–H/C(sp3)–H bonds.
Scheme 8: Cu-catalyzed synthesis of chiral 2-substituted tetrahydropyrans.
Scheme 9: CDC of thiazole with cyclic ethers.
Scheme 10: Cu(I)-catalyzed oxidative alkenylation of simple ethers.
Scheme 11: Cross-dehydrogenation coupling of isochroman C(sp3)–H bonds with anisole C(sp2)–H bonds.
Scheme 12: Pd(OAc)2/Cu(OTf)2-catalyzed arylation of α-C(sp3)–H bonds of ethers.
Scheme 13: Cu-catalyzed C(sp3)–H/C(sp2)–H activation strategies to construct C(sp3)–C(sp2) bonds.
Scheme 14: Cu(I)-catalyzed C(sp2)–H alkylation.
Scheme 15: Cu-catalyzed C(sp3)–H/C(sp)–H activation to construct C(sp3)–C(sp) bonds (H2BIP: 2,6-bis(benzimidaz...
Scheme 16: Fe-catalyzed CDC reaction pathways.
Scheme 17: Fe2(CO)9-catalyzed functionalization of C–H bonds.
Scheme 18: Ligand-promoted Fe-catalyzed CDC reaction of N-methylaniline with ethers.
Scheme 19: Fe-catalyzed CDC of C(sp3)–H/C(sp3)–H bonds.
Scheme 20: Fe-catalyzed hydroalkylation of α,β-unsaturated ketones with ethers.
Scheme 21: Solvent-free Fe(NO3)3-catalyzed CDC of C(sp3)–H/C(sp2)–H bonds.
Scheme 22: Alkylation of disulfide compounds to afford tetrasubstituted alkenes.
Scheme 23: Fe-catalyzed formation of 1,1-bis-indolylmethane derivatives.
Scheme 24: Alkylation of coumarins and flavonoids.
Scheme 25: Direct CDC α-arylation of azoles with ethers.
Scheme 26: CDC of terminal alkynes with C(sp3)–H bonds adjacent to oxygen, sulfur or nitrogen atoms.
Scheme 27: Alkylation of terminal alkynes.
Scheme 28: Co-catalyzed functionalization of glycine esters.
Scheme 29: Co-catalyzed construction of C(sp2)–C(sp3) bonds.
Scheme 30: Co-catalyzed CDC of imidazo[1,2-a]pyridines with isochroman.
Scheme 31: Co-catalyzed C–H alkylation of (benz)oxazoles with ethers.
Scheme 32: Cobalt-catalyzed CDC between unactivated C(sp2)–H and C(sp3)–H bonds.
Scheme 33: MnO2-catalyzed CDC of the inactive C(sp3)-H.
Scheme 34: Oxidative cross-coupling of ethers with enamides.
Scheme 35: Ni(II)-catalyzed CDC of indoles with 1,4-dioxane.
Scheme 36: Chemo- and regioselective ortho- or para-alkylation of pyridines.
Scheme 37: Asymmetric CDC of 3,6-dihydro-2H-pyrans with aldehydes.
Scheme 38: CDC of heterocyclic aromatics with ethers.
Scheme 39: Indium-catalyzed alkylation of DHPs with 1,3-dicarbonyl compounds.
Scheme 40: Rare earth-metal-catalyzed CDC reaction.
Scheme 41: Visible-light-driven CDC of cycloalkanes with benzazoles.
Scheme 42: Photoinduced alkylation of quinoline with cyclic ethers.
Scheme 43: Photocatalyzed CDC reactions between α-C(sp3)–H bonds of ethers and C(sp2)–H bonds of aromatics.
Cyanothioacetamides as a synthetic platform for the synthesis of aminopyrazole derivatives
- Valeriy O. Filimonov,
- Alexandra I. Topchiy,
- Vladimir G. Ilkin,
- Tetyana V. Beryozkina and
- Vasiliy A. Bakulev
Beilstein J. Org. Chem. 2023, 19, 1191–1197, doi:10.3762/bjoc.19.87
- mercaptopurine (Figure 1), containing an intracyclic thioamide group, are antagonists of purine bases and are well known as cytostatic drugs [13]. The thioamide group as an amide isostere is used in medical chemistry to increase thermal and proteolytic stability and improve the pharmacokinetic properties of
- biologically active substances containing amide groups [14]. The presence of a pyrazole core and a thioamide group within the hybrid molecules that we are planning to obtain, allows us to expect both an increase in their activity and the emergence of other types of biological activity, and also high synthetic
Graphical Abstract
Figure 1: Examples of bioactive pyrazoles for the protection of cultivated plants and drugs containing a thio...
Scheme 1: Syntheses of 4,5-diamino- and 4-thiocarbamoyl-5-aminopyrazoles.
Figure 2: Structures of starting materials.
Scheme 2: Synthesis of 3,5-diaminopyrazoles 4а–с and thiocarbamoyl-NH-pyrazoles 5a–e. Reaction conditions: 1a–...
Scheme 3: Synthesis of 1-aryl-5-amino-4-thiocarbamoylpyrazoles 6a–f. Reaction conditions: 2a–d (1 mmol), 3b,c...
Scheme 4: Synthesis of 1-sulfonylpyrazoles 7a–j and 1-benzoylpyrazole 7k. Conditions for 7a–j: 2b,d,e (1 mmol...
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
- ). Nucleophilic addition of the amine to the acyl radical and amine-assisted intermolecular proton transfer [84] generates the α-hydroxy radical 24 from which formation of the amide 25 proceeds either via i) oxidation by [Ir2]+ and deprotonation or ii) radical chain propagation [85]. Electron-deficient, electron
- partners. The scope of the protocol was further expanded to a radical cyclization/aminocarbonylation cascade reaction yielding the bis-carbonylated α-keto amide 26h in 31% yield. 2.1.2 C(sp3)–X activation: The generation of alkyl radicals using alkyl halides as precursors proves very challenging due their
Graphical Abstract
Figure 1: Oxidative and reductive activations of organic compounds harvesting photoredox catalysis.
Figure 2: General catalytic cycles of radical ion conPET (left) and radical ion e-PRC (right).
Figure 3: “Beginner’s guide”: comparison between advantages, capacities, and prospectives of conPET and PEC.
Figure 4: A) conPET reductive dehalogenation of aryl halides with PDI. B) Reductive C–H arylation with pyrrol...
Figure 5: A) Chromoselective mono- and disubstitution or polybrominated pyrimidines with pyrroles. B) Sequent...
Figure 6: A) Synthesis of pyrrolo[1,2-a]quinolines. B) Synthesis of ullazines.
Figure 7: A) Reductive phosphorylation of aryl halides via conPET. B) Selected examples from the substrate sc...
Figure 8: A) Reductive dehalogenation of aryl halides via conPET and selected examples from the substrate sco...
Figure 9: A) Reductive C–H arylation of aryl halides via conPET (top) and selected examples from the substrat...
Figure 10: A) Reductive hydrodehalogenation of aryl halides with Mes-Acr-BF4. B) Selected examples from the su...
Figure 11: A) Reductive hydrodechlorination of aryl chlorides with 4-DPAIPN. B) Proposed formation of CO2•−. C...
Figure 12: A) Reductive conPET borylation with 3CzEPAIPN (top) and selected examples from the substrate scope ...
Figure 13: Scale-up of conPET phosphorylation with 3CzEPAIPN.
Figure 14: A) Borylation of 1d. B) Characteristics and structure of PC1 with green and red parts showing the l...
Figure 15: A) Reductive C–H arylation scope with polysulfide conPET (top) and selected examples from the subst...
Figure 16: Scale-up of A) C–H arylation and B) dehaloborylation with polysulfide photocatalysis in continuous-...
Figure 17: A) Formation of [Ir1]0 and [Ir2]0 upon PET between [Ir1]+ and Et3N. B) Mechanism of multi-photon ta...
Figure 18: A) Reductive hydrodehalogenation of aryl halides via multi-photon tandem photocatalysis. B) Selecte...
Figure 19: A) Carbonylative amidation of aryl halides in continuous flow. B) Selected examples from the substr...
Figure 20: A) General scheme for reductive (RQ) and oxidative quenching (OQ) protocols using [FeIII(btz)3](PF6)...
Figure 21: A) Carbonylative amidation of alkyl iodides with [IrIII(ppy)2(dtbbpy)]PF6. B) Selected examples fro...
Figure 22: A) Carboxylative C–N bond cleavage in cyclic amines. B) Selected examples from the substrate scope....
Figure 23: A) Formal reduction of alkenes to alkanes via transfer hydrogenation. B) Selected examples from the...
Figure 24: A) Birch-type reduction of benzenes with PMP-BPI. B) Selected examples from the substrate scope (sc...
Figure 25: Proposed mechanism of the OH− mediated conPET Birch-type reduction of benzene via generation of sol...
Figure 26: Reductive detosylation of N-tosylated amides with Mes-Acr-BF4. B) Selected examples from the substr...
Figure 27: A) Reductive detosylation of N-tosyl amides by dual PRC. B) Selected examples from the substrate sc...
Figure 28: A) Mechanism of the dual PRC based on PET between [Cu(dap)2]+ and DCA. B) Mechanism of the dual PRC...
Figure 29: A) N–O bond cleavage in Weinreb amides with anthracene. B) N–O bond cleavage in Weinreb amides rely...
Figure 30: A) Pentafluorosulfanylation and fluoride elimination. B) Mechanism of the pentafluorosulfanylation ...
Figure 31: A) α-Alkoxypentafluorosulfanylation (top) and selected examples from the substrate scope (bottom). ...
Figure 32: A) Oxidative amination of arenes with azoles catalyzed by N-Ph PTZ. B) Selected examples from the s...
Figure 33: A) C(sp3)–H bond activation by HAT via chloride oxidation by *N-Ph PTZ•+. B) Proposed mechanism for...
Figure 34: A) Recycling e-PRC C–H azolation of electron-rich arenes with pyrazoles using Mes-Acr+ as a photoca...
Figure 35: A) Radical ion e-PRC direct oxidation of unactivated arenes using TAC+ as an electro-activated phot...
Figure 36: A) Radical ion e-PRC direct oxidation of unactivated arenes using TPA as an electro-activated photo...
Figure 37: Proposed mechanism (top) and mode of preassembly (bottom).
Figure 38: A) Possible preassemblies of reactive (left) vs unreactive (right) arenes. B) Calculated spin densi...
Figure 39: A) Recycling e-PRC C(sp2 )–H acetoxylation of arenes using DDQ as a photocatalyst. B) Proposed cata...
Figure 40: Gram scale hydroxylation of benzene in a recirculated flow setup.
Figure 41: A) Radical ion e-PRC vicinal diamination of alkylarenes using TAC+ as an electro-activated photocat...
Figure 42: A) Sequential oxygenation of multiple adjacent C–H bonds under radical ion e-PRC using TAC+ as an e...
Figure 43: A) Enantioselective recycling e-PRC cyanation of benzylic C–H bonds using ADQS as photocatalyst. B)...
Figure 44: Proposed tandem mechanism by Xu and co-workers.
Figure 45: A) Enantioselective recycling e-PRC decarboxylative cyanation using Cu(acac)2, Ce(OTf)3 and a box l...
Figure 46: A) Enantioselective recycling e-PRC benzylic cyanation using Cu(MeCN)4BF4, box ligand and anthraqui...
Figure 47: A) Radical ion e-PRC acetoxyhydroxylation of aryl olefins using TAC+ as an electro-activated photoc...
Figure 48: Selected examples from the substrate scope.
Figure 49: Photoelectrochemical acetoxyhydroxylation in a recirculated flow setup.
Figure 50: A) Radical ion e-PRC aminooxygenation of aryl olefins using TAC+ as an electro-activated photocatal...
Figure 51: A) Recycling e-PRC C–H alkylation of heteroarenes with organic trifluoroborates using Mes-Acr+ as p...
Figure 52: A) Recycling e-PRC decarboxylative C–H alkylation of heteroarenes using CeCl3·7H2O as catalyst. B) ...
Figure 53: A) Recycling e-PRC decarboxylative C–H alkylation of heteroarenes using Fe(NH4)2(SO4)2·6H2O as cata...
Figure 54: A) Recycling e-PRC C–H alkylation of heteroarenes with alkyl oxalates and 4CzIPN as photocatalyst. ...
Figure 55: A) Recycling e-PRC decarboxylative C–H carbamoylation of heteroarenes using 4CzIPN as photocatalyst...
Figure 56: A) Photoelectrochemical HAT-mediated hydrocarbon activation via the chlorine radical. B) Proposed m...
Figure 57: A) Selected examples from the substrate scope. B) Gram and decagram scale semi-continuous flow PEC ...
Figure 58: A) Photoelectrochemical HAT-mediated dehydrogenative coupling of benzothiazoles with aliphatic C–H ...
Figure 59: A) Photoelectrochemical HAT activation of ethers using electro-activated TAC+ as photocatalyst. B) ...
Figure 60: Selected examples from the substrate scope.
Figure 61: A) Photoelectrochemical HAT-mediated synthesis of alkylated benzimidazo-fused isoquinolinones using...
Figure 62: A) Decoupled photoelectrochemical cerium-catalyzed oxydichlorination of alkynes using CeCl3 as cata...
Figure 63: Proposed decoupled photoelectrochemical mechanism.
Figure 64: A) Decoupled photoelectrochemical ring-opening bromination of tertiary cycloalkanols using MgBr2 as...
Figure 65: A) Recycling e-PRC ring-opening functionalization of cycloalkanols using CeCl3 as catalyst. B) Prop...
Figure 66: Selected examples from the substrate scope of the PEC ring-opening functionalization.
Figure 67: A) Radical ion e-PRC reduction of chloro- and bromoarenes using DCA as catalyst and various accepto...
Figure 68: A) Screening of different phthalimide derivatives as catalyst for the e-PRC reduction of aryl halid...
Figure 69: Screening of different organic catalysts for the e-PRC reduction of trialkylanilium salts.
Figure 70: A) e-PRC reduction of phosphonated phenols and anilinium salts. B) Selected examples from the subst...
Figure 71: A) ConPET and e-PRC reduction of 4-bromobenzonitrile using a naphthalene diimide (NDI) precatalyst ...
Figure 72: A) Radical ion e-PRC reduction of phosphinated aliphatic alcohols with n-BuO-NpMI as catalyst. B) C...
Figure 73: Selected examples from the substrate scope.
Figure 74: A) Recycling e-PRC reductive dimerization of benzylic chlorides using a [Cu2] catalyst. B) Proposed...
Figure 75: A) Decoupled photoelectrochemical C–H alkylation of heteroarenes through deamination of Katritzky s...
Figure 76: Proposed mechanism by Chen and co-workers.
Aromatic C–H bond functionalization through organocatalyzed asymmetric intermolecular aza-Friedel–Crafts reaction: a recent update
- Anup Biswas
Beilstein J. Org. Chem. 2023, 19, 956–981, doi:10.3762/bjoc.19.72
- heteroarene and amide oxygen of 45 forcing the heteroarene to approach from the Si-face of the imine moiety predominantly (see transition state 48) achieving high enantiocontrol for both heterocycles (Scheme 13) [38]. The carbocyclic ring in indoles is less reactive than the heterocyclic ring and hence the
Graphical Abstract
Scheme 1: First organocatalyzed asymmetric aza-Friedel–Crafts reaction.
Scheme 2: Aza-Friedel–Crafts reaction between indoles and cyclic ketimines.
Scheme 3: Aza-Friedel–Crafts reaction utilizing trifluoromethyldihydrobenzoazepinoindoles as electrophiles.
Scheme 4: Aza-Friedel–Crafts reaction utilizing cyclic N-sulfimines as electrophiles.
Scheme 5: Aza-Friedel–Crafts reaction involving N-unprotected imino ester as electrophile.
Scheme 6: Aza-Friedel–Crafts and lactonization cascade.
Scheme 7: One-pot oxidation and aza-Friedel–Crafts reaction.
Scheme 8: C1 and C2-symmetric phosphoric acids as catalysts.
Scheme 9: Aza-Friedel–Crafts reaction using Nps-iminophosphonates as electrophiles.
Scheme 10: Aza-Friedel–Crafts reaction between indole and α-iminophosphonate.
Scheme 11: [2.2]-Paracyclophane-derived chiral phosphoric acids as catalyst.
Scheme 12: Aza-Friedel–Crafts reaction through ring opening of sulfamidates.
Scheme 13: Isoquinoline-1,3(2H,4H)-dione scaffolds as electrophiles.
Scheme 14: Functionalization of the carbocyclic ring of substituted indoles.
Scheme 15: Aza-Friedel–Crafts reaction between unprotected imines and aza-heterocycles.
Scheme 16: Anilines and α-naphthols as potential nucleophiles.
Scheme 17: Solvent-controlled regioselective aza-Friedel–Crafts reaction.
Scheme 18: Generating central and axial chirality via aza-Friedel–Crafts reaction.
Scheme 19: Reaction between indoles and racemic 2,3-dihydroisoxazol-3-ol derivatives.
Scheme 20: Exploiting 5-aminoisoxazoles as nucleophiles.
Scheme 21: Reaction between unsubstituted indoles and 3-alkynylated 3-hydroxy-1-oxoisoindolines.
Scheme 22: Synthesis of unnatural amino acids bearing an aza-quaternary stereocenter.
Scheme 23: Atroposelective aza-Friedel–Crafts reaction.
Scheme 24: Coupling of 5-aminopyrazole and 3H-indol-3-ones.
Scheme 25: Pyrophosphoric acid-catalyzed aza-Friedel–Crafts reaction on phenols.
Scheme 26: Squaramide-assisted aza-Friedel–Crafts reaction.
Scheme 27: Thiourea-catalyzed aza-Friedel–Crafts reaction.
Scheme 28: Squaramide-catalyzed reaction between β-naphthols and benzothiazolimines.
Scheme 29: Thiourea-catalyzed reaction between β-naphthol and isatin-derived ketamine.
Scheme 30: Quinine-derived molecule as catalyst.
Scheme 31: Cinchona alkaloid as catalyst.
Scheme 32: aza-Friedel–Crafts reaction by phase transfer catalyst.
Scheme 33: Disulfonamide-catalyzed reaction.
Scheme 34: Heterogenous thiourea-catalyzed aza-Friedel–Crafts reaction.
Scheme 35: Total synthesis of (+)-gracilamine.
Scheme 36: Total synthesis of (−)-fumimycin.
Photoredox catalysis enabling decarboxylative radical cyclization of γ,γ-dimethylallyltryptophan (DMAT) derivatives: formal synthesis of 6,7-secoagroclavine
- Alessio Regni,
- Francesca Bartoccini and
- Giovanni Piersanti
Beilstein J. Org. Chem. 2023, 19, 918–927, doi:10.3762/bjoc.19.70
- demonstrated by the formal total synthesis of (±)-6,7-secoagroclavine (Scheme 4) [108][109][110][111][112][113][114]. Towards this end, compound 11 was methylated efficiently and selectively at the secondary amide by treatment with methyl iodide in DMF to afford compound 13. In additional two steps
Graphical Abstract
Figure 1: (a) Transformations of DMAT to different classes of ergot alkaloids. (b) and (c) Strategies for the...
Scheme 1: Synthesis of compound 5.
Scheme 2: Photoredox-catalyzed radical decarboxylative cyclization of 5.
Figure 2: Proposed reaction mechanism for photoredox-catalyzed radical decarboxylative cyclization.
Scheme 3: Synthesis of tryptophan derivatives 8 and 10.
Figure 3: Proposed reaction mechanism for photoredox-catalyzed radical decarboxylative cyclization.
Scheme 4: Methylation of 11 and the formal total synthesis of (±)-6,7-secoagroclavine.
Intermediates and shunt products of massiliachelin biosynthesis in Massilia sp. NR 4-1
- Till Steinmetz,
- Blaise Kimbadi Lombe and
- Markus Nett
Beilstein J. Org. Chem. 2023, 19, 909–917, doi:10.3762/bjoc.19.69
- signal at δH 7.62 ppm characteristic for an amide. In vitro tests were conducted for all compounds to assess their antibacterial activities against three Gram-negative bacteria (Escherichia coli, Agrobacterium tumefaciens and Pseudomonas fluorescens) and one Gram-positive bacterium (Bacillus subtilis
Graphical Abstract
Figure 1: Selected siderophores from β-proteobacteria.
Figure 2: Chemical structures of compounds 1–6 isolated in this study and of the structurally related siderop...
Figure 3: 1H,1H-COSY and selected 1H,13C-HMBC correlations in 1.
Figure 4: Proposed origin of the isolated compounds 1–6 as well as massiliachelin (7). Domain notation of the...
Asymmetric tandem conjugate addition and reaction with carbocations on acylimidazole Michael acceptors
- Brigita Mudráková,
- Renata Marcia de Figueiredo,
- Jean-Marc Campagne and
- Radovan Šebesta
Beilstein J. Org. Chem. 2023, 19, 881–888, doi:10.3762/bjoc.19.65
- its applications in the total syntheses of complex natural products and other molecules of biological relevance [13][14]. Acylimidazoles proved to be versatile building blocks broadly applicable in asymmetric catalysis and organic synthesis. Today, acylimidazoles are used as ester/amide surrogates
- , because of their particular chemical and physical properties [15]. In addition to ester/amide synthesis, enoyl imidazolides were developed as excellent Michael acceptors. Acylimidazoles are unique electrophiles that demonstrate moderate reactivity, relatively high stability, chemical selectivity, and high
Graphical Abstract
Scheme 1: Concept of this work.
Scheme 2: Initial experiments for the trapping of the intermediate enolate Enl-1a with tropylium NTf2.
Scheme 3: The reaction scope.
Figure 1: Comparison of DFT-calculated and experimental ECD of (2R,3R)-4 and (2S,3R)-4.
Figure 2: DFT calculated (ωB97X-D4/def2-TZVPPD//PBEh-3c/def2-mSVP) HOMO energies and NBO charges for represen...
Pyridine C(sp2)–H bond functionalization under transition-metal and rare earth metal catalysis
- Haritha Sindhe,
- Malladi Mounika Reddy,
- Karthikeyan Rajkumar,
- Akshay Kamble,
- Amardeep Singh,
- Anand Kumar and
- Satyasheel Sharma
Beilstein J. Org. Chem. 2023, 19, 820–863, doi:10.3762/bjoc.19.62
- tricyclic imidazonaphthyridinone derivative having antibacterial properties, with low catalyst loading (0.1 mol %) (Scheme 20b). Later, in 2014, the same authors, using an amide as directing group (DG), developed a protocol for the regioselective C3-alkenylation of pyridines through syn-addition of alkynes
- (0)/PR3-catalyzed C3 or C4-arylation of nicotinic and isonicotinic acids using amide as a directing group (Scheme 27) [97]. This method provides a way for arylated nicotinic acid derivatives which serve as building blocks for biologically important molecules. This was the first report for a directing
- 205 were accessed in moderate to excellent yields and also naphthyridine derivatives (205k and 205l) were synthesized. In the proposed mechanism, the initial deprotonation of HNBn2 by Ln[N(TMS)2]3 provided the lanthanide amide. Activation of the vinyl-substituted pyridin-3-amine 204 by the lanthanide
Graphical Abstract
Figure 1: Representative examples of bioactive natural products and FDA-approved drugs containing a pyridine ...
Scheme 1: Classical and traditional methods for the synthesis of functionalized pyridines.
Scheme 2: Rare earth metal (Ln)-catalyzed pyridine C–H alkylation.
Scheme 3: Pd-catalyzed C–H alkylation of pyridine N-oxide.
Scheme 4: CuI-catalyzed C–H alkylation of N-iminopyridinium ylides with tosylhydrazones (A) and a plausible r...
Scheme 5: Zirconium complex-catalyzed pyridine C–H alkylation.
Scheme 6: Rare earth metal-catalyzed pyridine C–H alkylation with nonpolar unsaturated substrates.
Scheme 7: Heterobimetallic Rh–Al complex-catalyzed ortho-C–H monoalkylation of pyridines.
Scheme 8: Mono(phosphinoamido)-rare earth complex-catalyzed pyridine C–H alkylation.
Scheme 9: Rhodium-catalyzed pyridine C–H alkylation with acrylates and acrylamides.
Scheme 10: Ni–Al bimetallic system-catalyzed pyridine C–H alkylation.
Scheme 11: Iridium-catalyzed pyridine C–H alkylation.
Scheme 12: para-C(sp2)–H Alkylation of pyridines with alkenes.
Scheme 13: Enantioselective pyridine C–H alkylation.
Scheme 14: Pd-catalyzed C2-olefination of pyridines.
Scheme 15: Ru-catalyzed C-6 (C-2)-propenylation of 2-arylated pyridines.
Scheme 16: C–H addition of allenes to pyridines catalyzed by half-sandwich Sc metal complex.
Scheme 17: Pd-catalyzed stereodivergent synthesis of alkenylated pyridines.
Scheme 18: Pd-catalyzed ligand-promoted selective C3-olefination of pyridines.
Scheme 19: Mono-N-protected amino acids in Pd-catalyzed C3-alkenylation of pyridines.
Scheme 20: Amide-directed and rhodium-catalyzed C3-alkenylation of pyridines.
Scheme 21: Bimetallic Ni–Al-catalyzed para-selective alkenylation of pyridine.
Scheme 22: Arylboronic ester-assisted pyridine direct C–H arylation.
Scheme 23: Pd-catalyzed C–H arylation/benzylation with toluene.
Scheme 24: Pd-catalyzed pyridine C–H arylation with potassium aryl- and heteroaryltrifluoroborates.
Scheme 25: Transient activator strategy in pyridine C–H biarylation.
Scheme 26: Ligand-promoted C3-arylation of pyridine.
Scheme 27: Pd-catalyzed arylation of nicotinic and isonicotinic acids.
Scheme 28: Iron-catalyzed and imine-directed C–H arylation of pyridines.
Scheme 29: Pd–(bipy-6-OH) cooperative system-mediated direct pyridine C3-arylation.
Scheme 30: Pd-catalyzed pyridine N-oxide C–H arylation with heteroarylcarboxylic acids.
Scheme 31: Pd-catalyzed C–H cross-coupling of pyridine N-oxides with five-membered heterocycles.
Scheme 32: Cu-catalyzed dehydrative biaryl coupling of azine(pyridine) N-oxides and oxazoles.
Scheme 33: Rh(III)-catalyzed cross dehydrogenative C3-heteroarylation of pyridines.
Scheme 34: Pd-catalyzed C3-selective arylation of pyridines.
Scheme 35: Rhodium-catalyzed oxidative C–H annulation of pyridines to quinolines.
Scheme 36: Rhodium-catalyzed and NHC-directed C–H annulation of pyridine.
Scheme 37: Ni/NHC-catalyzed regio- and enantioselective C–H cyclization of pyridines.
Scheme 38: Rare earth metal-catalyzed intramolecular C–H cyclization of pyridine to azaindolines.
Scheme 39: Rh-catalyzed alkenylation of bipyridine with terminal silylacetylenes.
Scheme 40: Rollover cyclometallation in Rh-catalyzed pyridine C–H functionalization.
Scheme 41: Rollover pathway in Rh-catalyzed C–H functionalization of N,N,N-tridentate chelating compounds.
Scheme 42: Pd-catalyzed rollover pathway in bipyridine-6-carboxamides C–H arylation.
Scheme 43: Rh-catalyzed C3-acylmethylation of bipyridine-6-carboxamides with sulfoxonium ylides.
Scheme 44: Rh-catalyzed C–H functionalization of bipyridines with alkynes.
Scheme 45: Rh-catalyzed C–H acylmethylation and annulation of bipyridine with sulfoxonium ylides.
Scheme 46: Iridium-catalyzed C4-borylation of pyridines.
Scheme 47: C3-Borylation of pyridines.
Scheme 48: Pd-catalyzed regioselective synthesis of silylated dihydropyridines.
