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Search for "bromination" in Full Text gives 231 result(s) in Beilstein Journal of Organic Chemistry. Showing first 200.
One-pot synthesis of dicyclopenta-fused peropyrene via a fourfold alkyne annulation
- Ji Ma,
- Yubin Fu,
- Junzhi Liu and
- Xinliang Feng
Beilstein J. Org. Chem. 2020, 16, 791–797, doi:10.3762/bjoc.16.72
- selective bromination of 4 with 4.4 equiv of bromine in nitrobenzene solution at 120 °C afforded 1,3,6,8-tetrabromo-2,7-diphenylpyrene (5) in excellent yield (86%). Compared to insoluble 1,3,6,8-tetrabromopyrene [34], the diphenyl-substituted compound 5 exhibited excellent solubility in common organic
Graphical Abstract
Scheme 1: Chemical structures of dicyclopenta-fused pyrene derivatives i–iii, peropyrene and the dicyclopenta...
Scheme 2: Synthetic route towards compound 1. a) B2pin2, dtbpy, [Ir(OMe)cod]2, cyclohexane, 70 °C, 20 h, 67%;...
Figure 1: High-resolution MALDI-TOF mass spectrum of 1. Inset: isotopic distribution compared to mass spectru...
Figure 2: Single-crystal X-ray structure of 1. (a) Top view and (b) side view of the (P,P) isomer. c) Crystal...
Figure 3: (a) UV–vis absorption spectra of precursor 5 and 1 in CH2Cl2 solution (10−5 M). Inset: photograph o...
Figure 4: Molecular orbitals of peropyrene derivative 6 and the dicyclopenta-fused peropyrene 1.
Towards triptycene functionalization and triptycene-linked porphyrin arrays
- Gemma M. Locke,
- Keith J. Flanagan and
- Mathias O. Senge
Beilstein J. Org. Chem. 2020, 16, 763–777, doi:10.3762/bjoc.16.70
- bromination of 17a [42] (Scheme 3). The coupling reaction was initially carried out with (5,15-dibromo-10,20-dihexyl/diphenyl)porphyrinato)zinc(II) but both porphyrins had extremely low solubility. Using the more soluble 17c gave access to the triptycene–porphyrin–triptycene complex 18. The reaction was
Graphical Abstract
Figure 1: Triptycene as a scaffold and selected porphyrin and BODIPY arrays.
Scheme 1: Sonogashira cross-coupling reactions to form symmetric porphyrin and BODIPY triptycene-linked dyads....
Scheme 2: Sonogashira cross-coupling reactions to form a triptycene-substituted porphyrin monomer and an unsy...
Scheme 3: Synthesis of the triptycene-porphyrin-triptycene complex 18.
Figure 2: Single crystal X-ray structure of triptycene 5. (a) Molecular structure of 5 in the crystal with hy...
Figure 3: Single crystal X-ray structure of triptycene-linked zinc-nickel porphyrin dimer 16 showing the conf...
Figure 4: Views of the single crystal X-ray structure of triptycene-linked zinc-nickel porphyrin dimer 16 sho...
Figure 5: Expanded structure view of the triptycene-linked zinc-nickel porphyrin dimer 16 showing the repeati...
Figure 6: UV–vis of symmetric and unsymmetric triptycene porphyrin dimers 9 and 16, and the triptycene porphy...
Figure 7: Emission spectrum of symmetric and unsymmetric triptycene-linked porphyrin dimers 9 and 16, and a t...
Figure 8: Compounds used for spectroscopic comparisons.
Figure 9: UV–vis spectra of various porphyrin/BODIPY dimers with different linker groups in CHCl3.
Figure 10: Fluorescence emission spectrum of various porphyrin/BODIPY dimers with different linker groups in C...
Regioselectively α- and β-alkynylated BODIPY dyes via gold(I)-catalyzed direct C–H functionalization and their photophysical properties
- Takahide Shimada,
- Shigeki Mori,
- Masatoshi Ishida and
- Hiroyuki Furuta
Beilstein J. Org. Chem. 2020, 16, 587–595, doi:10.3762/bjoc.16.53
- ., bromination) of BODIPY derivatives often affords a mixture of multiply halogenated products, which is tedious to separate by column chromatography. The introduction of one or more alkynyl groups into the BODIPY skeleton indeed produces useful building blocks for functional π-materials. For example, ethynyl
Graphical Abstract
Figure 1: (a) Chemical structures of BODIPY (1) and dipyrromethane (2). (b) C–C bond forming alkynylations of...
Scheme 1: Synthesis of α-ethynyl-substituted BODIPY derivatives 3a and 4a.
Scheme 2: Synthesis of β-ethynyl-substituted BODIPY derivatives 5a and 5b and β,β'-diethynyl-substituted comp...
Figure 2: Top and front views of the crystal structures of (a) 4a and (b) 6b with 50% thermal ellipsoid proba...
Figure 3: Partial 1H NMR spectra of (a) 1a, (b) 3a, (c) 4a, (d) 5a, and (e) 6a recorded in CDCl3 at 298 K. As...
Figure 4: UV–vis absorption spectra of the BODIPY derivatives, (a) 1a (green), 3a (blue), 4a (red), and (b) 1a...
Figure 5: Fluorescence spectra of BODIPY derivatives. (a) 1a (green), 3a (blue), 4a (red) and (b) 1a (green), ...
Recent advances in photocatalyzed reactions using well-defined copper(I) complexes
- Mingbing Zhong,
- Xavier Pannecoucke,
- Philippe Jubault and
- Thomas Poisson
Beilstein J. Org. Chem. 2020, 16, 451–481, doi:10.3762/bjoc.16.42
- heteroaromatic derivatives. Noteworthy, when the reaction was carried out in acetonitrile, azido bromination and diazidation reactions were possible using 10 equivalents of NaBr and NaN3, respectively. Notably, when the reaction was carried out in the dark, the diazidation reaction of the olefins occurred, while
Graphical Abstract
Scheme 1: [Cu(I)(dap)2]Cl-catalyzed ATRA reaction under green light irradiation.
Scheme 2: Photocatalytic allylation of α-haloketones.
Scheme 3: [Cu(I)(dap)2]Cl-photocatalyzed chlorosulfonylation and chlorotrifluoromethylation of alkenes.
Scheme 4: Photocatalytic perfluoroalkylchlorination of electron-deficient alkenes using the Sauvage catalyst.
Scheme 5: Photocatalytic synthesis of fluorinated sultones.
Scheme 6: Photocatalyzed haloperfluoroalkylation of alkenes and alkynes.
Scheme 7: Chlorosulfonylation of alkenes catalyzed by [Cu(I)(dap)2]Cl. aNo Na2CO3 was added. b1 equiv of Na2CO...
Scheme 8: Copper-photocatalyzed reductive allylation of diaryliodonium salts.
Scheme 9: Copper-photocatalyzed azidomethoxylation of olefins.
Scheme 10: Benzylic azidation initiated by [Cu(I)(dap)2]Cl.
Scheme 11: Trifluoromethyl methoxylation of styryl derivatives using [Cu(I)(dap)2]PF6. All redox potentials ar...
Scheme 12: Trifluoromethylation of silyl enol ethers.
Scheme 13: Synthesis of annulated heterocycles upon oxidation with the Sauvage catalyst.
Scheme 14: Oxoazidation of styrene derivatives using [Cu(dap)2]Cl as a precatalyst.
Scheme 15: [Cu(I)(dpp)(binc)]PF6-catalyzed ATRA reaction.
Scheme 16: Allylation reaction of α-bromomalonate catalyzed by [Cu(I)(dpp)(binc)]PF6 following an ATRA mechani...
Scheme 17: Bromo/tribromomethylation reaction using [Cu(I)(dmp)(BINAP)]PF6.
Scheme 18: Chlorotrifluoromethylation of alkenes catalyzed by [Cu(I)(N^N)(xantphos)]PF6.
Scheme 19: Chlorosulfonylation of styrene and alkyne derivatives by ATRA reactions.
Scheme 20: Reduction of aryl and alkyl halides with the complex [Cu(I)(bcp)(DPEPhos)]PF6. aIrradiation was car...
Scheme 21: Meerwein arylation of electron-rich aromatic derivatives and 5-exo-trig cyclization catalyzed by th...
Scheme 22: [Cu(I)(bcp)(DPEPhos)]PF6-photocatalyzed synthesis of alkaloids. aYield over two steps (cyclization ...
Scheme 23: Copper-photocatalyzed decarboxylative amination of NHP esters.
Scheme 24: Photocatalytic decarboxylative alkynylation using [Cu(I)(dq)(binap)]BF4.
Scheme 25: Copper-photocatalyzed alkylation of glycine esters.
Scheme 26: Copper-photocatalyzed borylation of organic halides. aUnder continuous flow conditions.
Scheme 27: Copper-photocatalyzed α-functionalization of alcohols with glycine ester derivatives.
Scheme 28: δ-Functionalization of alcohols using [Cu(I)(dmp)(xantphos)]BF4.
Scheme 29: Photocatalytic synthesis of [5]helicene and phenanthrene.
Scheme 30: Oxidative carbazole synthesis using in situ-formed [Cu(I)(dmp)(xantphos)]BF4.
Scheme 31: Copper-photocatalyzed functionalization of N-aryl tetrahydroisoquinolines.
Scheme 32: Bicyclic lactone synthesis using a copper-photocatalyzed PCET reaction.
Scheme 33: Photocatalytic Pinacol coupling reaction catalyzed by [Cu(I)(pypzs)(BINAP)]BF4. The ligands of the ...
Scheme 34: Azide photosensitization using a Cu-based photocatalyst.
Recent developments in photoredox-catalyzed remote ortho and para C–H bond functionalizations
- Rafia Siddiqui and
- Rashid Ali
Beilstein J. Org. Chem. 2020, 16, 248–280, doi:10.3762/bjoc.16.26
- photolysis. The mechanism involved in this transformation is shown in Figure 20. Aryl C–H halogenation Aerobic bromination of arenes: In another experiment, Ohkubo et al. reported that for aerobic aryl C–H brominations, HBr can be utilized with photoredox catalyst 2 in the presence of molecular oxygen to
- compounds via an oxidative photocatalytic pathway [164]. They performed the reaction in the presence of organic photoredox catalyst 1,2,3,5-tetrakis(carbazol-9-yl)-4,6-dicyanobenzene (5a, 4CzIPN), environment friendly oxygen, and hydrochloride as a chloride source. The activation proceeded via bromination
- of substituted phenols using QuCN. Synthesis of substituted phenols with DDQ (5). Aerobic bromination of arenes using an acridinium-based photocatalyst. Aerobic bromination of arenes with anthraquinone. Chlorination of benzene derivatives with Mes-Acr-MeClO4 (2). Chlorination of arenes with 4CzIPN
Graphical Abstract
Figure 1: List of photoredox catalysts used for C–H bond functionalizations.
Figure 2: List of metal-based photoredox catalysts used in this review article.
Figure 3: Jablonski diagram.
Figure 4: Photoredox catalysis via reductive or oxidative pathways. D = donor, A = acceptor, S = substrate, P...
Figure 5: Schematic representation of the combination of photoredox catalysis and transition metal catalysis.
Scheme 1: Weinreb amide C–H olefination.
Figure 6: Mechanism for the formation of 21 from 19 using photoredox catalyst 11.
Scheme 2: C–H olefination of phenolic ethers.
Scheme 3: Decarboxylative acylation of acetanilides.
Figure 7: Mechanism for the formation of 30 from acetanilide derivatives.
Scheme 4: Synthesis of fluorenone derivatives by intramolecular deoxygenative acylation of biaryl carboxylic ...
Figure 8: Mechanism for the photoredox-catalyzed synthesis of fluorenone derivatives.
Scheme 5: Synthesis of benzothiazoles via aerobic C–H thiolation.
Figure 9: Plausible mechanism for the construction of benzothiazoles from benzothioamides.
Scheme 6: Synthesis of benzothiazoles via oxidant-free C–H thiolation.
Figure 10: Mechanism involved in the synthesis of benzothiazoles via oxidant-free C–H thiolation.
Scheme 7: Synthesis of indoles via C–H cyclization of anilides with alkynes.
Scheme 8: Preparation of 3-trifluoromethylcoumarins via C–H cyclization of arylpropiolate esters.
Figure 11: Mechanistic pathway for the synthesis of coumarin derivatives via C–H cyclization.
Scheme 9: Monobenzoyloxylation without chelation assistance.
Figure 12: Plausible mechanism for the formation of 71 from 70.
Scheme 10: Aryl-substituted arenes prepared by inorganic photoredox catalysis using 12a.
Figure 13: Proposed mechanism for C–H arylations in the presence of 12a and a Pd catalyst.
Scheme 11: Arylation of purines via dual photoredox catalysis.
Scheme 12: Arylation of substituted arenes with an organic photoredox catalyst.
Scheme 13: C–H trifluoromethylation.
Figure 14: Proposed mechanism for the trifluoromethylation of 88.
Scheme 14: Synthesis of benzo-3,4-coumarin derivatives.
Figure 15: Plausible mechanism for the synthesis of substituted coumarins.
Scheme 15: Oxidant-free oxidative phosphonylation.
Figure 16: Mechanism proposed for the phosphonylation reaction of 100.
Scheme 16: Nitration of anilines.
Figure 17: Plausible mechanism for the nitration of aniline derivatives via photoredox catalysis.
Scheme 17: Synthesis of carbazoles via intramolecular amination.
Figure 18: Proposed mechanism for the formation of carbazoles from biaryl derivatives.
Scheme 18: Synthesis of substituted phenols using QuCN.
Figure 19: Mechanism for the synthesis of phenol derivatives with photoredox catalyst 8.
Scheme 19: Synthesis of substituted phenols with DDQ (5).
Figure 20: Possible mechanism for the generation of phenols with the aid of photoredox catalyst 5.
Scheme 20: Aerobic bromination of arenes using an acridinium-based photocatalyst.
Scheme 21: Aerobic bromination of arenes with anthraquinone.
Figure 21: Proposed mechanism for the synthesis of monobrominated compounds.
Scheme 22: Chlorination of benzene derivatives with Mes-Acr-MeClO4 (2).
Figure 22: Mechanism for the synthesis of 131 from 132.
Scheme 23: Chlorination of arenes with 4CzIPN (5a).
Figure 23: Plausible mechanism for the oxidative photocatalytic monochlorination using 5a.
Scheme 24: Monofluorination using QuCN-ClO4 (8).
Scheme 25: Fluorination with fluorine-18.
Scheme 26: Aerobic amination with acridinium catalyst 3a.
Figure 24: Plausible mechanism for the aerobic amination using acridinium catalyst 3a.
Scheme 27: Aerobic aminations with semiconductor photoredox catalyst 18.
Scheme 28: Perfluoroalkylation of arenes.
Scheme 29: Synthesis of benzonitriles in the presence of 3a.
Figure 25: Plausible mechanism for the synthesis of substituted benzonitrile derivatives in the presence of 3a....
Palladium-catalyzed synthesis and nucleotide pyrophosphatase inhibition of benzo[4,5]furo[3,2-b]indoles
- Hoang Huy Do,
- Saif Ullah,
- Alexander Villinger,
- Joanna Lecka,
- Jean Sévigny,
- Peter Ehlers,
- Jamshed Iqbal and
- Peter Langer
Beilstein J. Org. Chem. 2019, 15, 2830–2839, doi:10.3762/bjoc.15.276
- literature procedure, 2,3-dibromobenzofuran (1) was synthesized by bromination of benzofuran [33]. The Suzuki–Miyaura reaction of 1 with 2-bromophenylboronic acid (2), carried out under standard conditions using Pd(PPh3)4, afforded the desired product 3 in 84% yield and with very good regioselectivity. The
Graphical Abstract
Figure 1: Pharmacologically relevant furoindoles.
Scheme 1: Synthesis of benzo[4,5]furo[3,2-b]indoles 5a–j. Conditions: (i) 1.2 equiv 2-bromophenylboronic acid...
Figure 2: Ortep of 5c (propability of ellipsoids: 45%).
Figure 3: Diindolofurans 6a–e.
Figure 4: Illustration of binding poses of selected inhibitors for the ENPP1 homology model: (a): suramin, (b...
Figure 5: 3D poses of docked selected inhibitors inside homology model of ENPP3. (a): suramin, (b): 5e, (c): ...
Chemical tuning of photoswitchable azobenzenes: a photopharmacological case study using nicotinic transmission
- Lorenzo Sansalone,
- Jun Zhao,
- Matthew T. Richers and
- Graham C. R. Ellis-Davies
Beilstein J. Org. Chem. 2019, 15, 2812–2821, doi:10.3762/bjoc.15.274
- catalytic hydrogenation to 4 followed by protection with TBDMS to give 5 in 63% yield for three steps. The synthesis of the other half of the photochrome started with bromination of difluorinated aniline to give 6 followed by copper-catalyzed cyanation to 7 in 62% overall yield. Diazonization of 7 with
- % overall yield. Installation of the cationic head was performed in two steps: first bromination of 11 via Appel reaction, followed by treatment with trimethylamine to give 2 in 35% overall yield. Photoswitch 2 is the first example of a bifunctional, asymmetrically substituted 4FAB chromophore that actually
Graphical Abstract
Figure 1: Fluoro-AB derivatives and spectra. Structures of 4FAB-diamides [13] cis and trans configurations, and t...
Scheme 1: Synthesis of 4FABTA. a) Reagents and conditions: (a) 3-Butynol, PdCl2(PPh3)2, CuI, THF, rt, 93%; (b...
Figure 2: Photochemistry of 4FABTA (2), and thermodynamic stability in physiological buffer. a) Trans–cis pho...
Figure 3: Reaction of t-4FABTA (1) with thiols, and thermal stability of initial conjugate. a) Chemical react...
Figure 4: Testing photo-antagonism of 1 with genetically tagged nicotinic acetylcholine receptors. Currents f...
Figure 5: Photopharmacology with 4FABTA (2). Currents from neurons in the medial habenula in acutely isolated...
An improved, scalable synthesis of Notum inhibitor LP-922056 using 1-chloro-1,2-benziodoxol-3-one as a superior electrophilic chlorinating agent
- Nicky J. Willis,
- Elliott D. Bayle,
- George Papageorgiou,
- David Steadman,
- Benjamin N. Atkinson,
- William Mahy and
- Paul V. Fish
Beilstein J. Org. Chem. 2019, 15, 2790–2797, doi:10.3762/bjoc.15.271
- functionalised for the introduction of the C7-cyclopropyl group, the C6-chlorine atom and elaboration of the thioacetic acid moiety at C4. Electrophilic bromination at C7 with N-bromosuccinimide gave 5 as the major regioisomer reproducibly on 100 mmol scale in modest yield (41–48%). This proved to be the least
- –26%) and high purity (>99%). Improved synthesis of 1; second generation A shorter synthesis was then developed by accessing bromide 5 by an alternative route. The low-yielding C7 bromination of 4 with NBS to give 5 as described above (Scheme 1, step c) was avoided by starting with 7-bromo-4
Graphical Abstract
Figure 1: Chemical structure of Notum inhibitor LP-922056 (1).
Scheme 1: Synthesis of LP-922056 (1). Reagents and conditionsa: (a) (COCl)2 (3.3 equiv), DMF, CH2Cl2, 55 °C ,...
Scheme 2: Chlorination of 6 with N-chlorosuccinimide (NCS). Reagents and conditions: (a) NCS (1.2 equiv), AcO...
Scheme 3: Improved synthesis of 5. Reagents and conditions: (a) NaOMe (5 equiv), 1,4-dioxane, 0 °C then rt, 1...
Figure 2: Concentrations of 1 in mouse following oral administration (p.o.) at 10 mg/kg.
Scheme 4: Preparation of amides 17. Representative reagents and conditionsa: (a) HBTU (1.1 equiv), iPr2NEt (2...
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
- ligands. The reaction with pinacolborane (HB(pin)) gave ester 9 in 97% yield [11]. Another ester (10) was synthesized by bromination of 3-thiopheneacetic acid with NBS (applying an ultrasound bath) followed by esterification of the crude product with methanol in the presence of sulfuric acid [12]. Other
Graphical Abstract
Figure 1: Structures of “thiophenylated” DAEs prepared and studied in this work.
Scheme 1: Synthesis routes towards mono- and diiodinated core structures 4, 5, 7, and 8.
Scheme 2: Synthesis of thiophene- and bithiopheneboronic esters 9 and 12 (bpy – 4,4’-di-tert-butyl-2,2’-dipyr...
Scheme 3: Photoswitchable diarylethenes AsTh1, SyTh1, AsTh2, SyTh2, AsOTh1, SyOTh1, AsOTh2, and SyOTh2 synthe...
Scheme 4: Saponification of methyl ester groups in tetraester SyTh2 leading to tetracarboxylic acid SyTh2-H.
Figure 2: Absorption (A) and emission (B) spectra of SyTh2 in acetonitrile in the course of the cyclization r...
Figure 3: Absorption spectra of the OFs (A) and CFs (B) of AsTh1 (a), SyTh1 (b), AsTh2 (c), SyTh2 (d), AsOTh1...
Figure 4: Solutions of compounds AsTh1 (a), SyTh1 (b), AsTh2 (c), SyTh2 (d), AsOTh1 (e), SyOTh1 (f), AsOTh2 (...
Figure 5: Fatigue resistances of compounds SyOTh1 (A and B) and SyTh1 (C). Parts A and C show the absorbance ...
Figure 6: (A) Absorption spectra of compound SyOTh1 in MeCN at the photostationary states under irradiation w...
A review of the total syntheses of triptolide
- Xiang Zhang,
- Zaozao Xiao and
- Hongtao Xu
Beilstein J. Org. Chem. 2019, 15, 1984–1995, doi:10.3762/bjoc.15.194
- and reacted with 3,3-dimethylallyl bromide, followed by changing the protecting group from MOM ether to methyl ether to provide olefin 86. Allylic oxidation of 86 followed by nucleophilic bromination of the resulting allylic alcohol gave bromide 87. Dianion displacement of the bromide of 87 gave ester
Graphical Abstract
Figure 1: Structures of triptolide (1), triptonide (2), tripdiolide (3), 16-hydroxytriptolide (4), triptrioli...
Figure 2: Syntheses of triptolide.
Scheme 1: Berchtold’s synthesis of triptolide.
Scheme 2: Li’s formal synthesis of triptolide.
Scheme 3: van Tamelen’s asymmetric synthesis of triptonide and triptolide.
Scheme 4: Van Tamelen’s (method II) formal synthesis of triptolide.
Scheme 5: Sherburn’s formal synthesis of triptolide.
Scheme 6: van Tamelen’s biogenetic type total synthesis of triptolide.
Scheme 7: Yang’s total synthesis of triptolide.
Scheme 8: Key intermediates or transformations of routes J–N.
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
Figure 1: Various drugs having IP nucleus.
Figure 2: Participation percentage of various TMs for the syntheses of IPs.
Scheme 1: CuI–NaHSO4·SiO2-catalyzed synthesis of imidazo[1,2-a]pyridines.
Scheme 2: Experimental examination of reaction conditions.
Scheme 3: One-pot tandem reaction for the synthesis of 2-haloimidazopyridines.
Scheme 4: Mechanistic scheme for the synthesis of 2-haloimidazopyridine.
Scheme 5: Copper-MOF-catalyzed three-component reaction (3-CR) for imidazo[1,2-a]pyridines.
Scheme 6: Mechanism for copper-MOF-driven synthesis.
Scheme 7: Heterogeneous synthesis via titania-supported CuCl2.
Scheme 8: Mechanism involving oxidative C–H functionalization.
Scheme 9: Heterogeneous synthesis of IPs.
Scheme 10: One-pot regiospecific synthesis of imidazo[1,2-a]pyridines.
Scheme 11: Vinyl azide as an unprecedented substrate for imidazo[1,2-a]pyridines.
Scheme 12: Radical pathway.
Scheme 13: Cu(I)-catalyzed transannulation approach for imidazo[1,5-a]pyridines.
Scheme 14: Plausible radical pathway for the synthesis of imidazo[1,5-a]pyridines.
Scheme 15: A solvent-free domino reaction for imidazo[1,2-a]pyridines.
Scheme 16: Cu-NPs-mediated synthesis of imidazo[1,2-a]pyridines.
Scheme 17: CuI-catalyzed synthesis of isoxazolylimidazo[1,2-a]pyridines.
Scheme 18: Functionalization of 4-bromo derivative via Sonogashira coupling reaction.
Scheme 19: A plausible reaction pathway.
Scheme 20: Cu(I)-catalyzed intramolecular oxidative C–H amidation reaction.
Scheme 21: One-pot synthetic reaction for imidazo[1,2-a]pyridine.
Scheme 22: Plausible reaction mechanism.
Scheme 23: Cu(OAc)2-promoted synthesis of imidazo[1,2-a]pyridines.
Scheme 24: Mechanism for aminomethylation/cycloisomerization of propiolates with imines.
Scheme 25: Three-component synthesis of imidazo[1,2-a]pyridines.
Figure 3: Scope of pyridin-2(1H)-ones and acetophenones.
Scheme 26: CuO NPS-promoted A3 coupling reaction.
Scheme 27: Cu(II)-catalyzed C–N bond formation reaction.
Scheme 28: Mechanism involving Chan–Lam/Ullmann coupling.
Scheme 29: Synthesis of formyl-substituted imidazo[1,2-a]pyridines.
Scheme 30: A tandem sp3 C–H amination reaction.
Scheme 31: Probable mechanistic approach.
Scheme 32: Dual catalytic system for imidazo[1,2-a]pyridines.
Scheme 33: Tentative mechanism.
Scheme 34: CuO/CuAl2O4/ᴅ-glucose-promoted 3-CCR.
Scheme 35: A tandem CuOx/OMS-2-based synthetic strategy.
Figure 4: Biomimetic catalytic oxidation in the presence of electron-transfer mediators (ETMs).
Scheme 36: Control experiment.
Scheme 37: Copper-catalyzed C(sp3)–H aminatin reaction.
Scheme 38: Reaction of secondary amines.
Scheme 39: Probable mechanistic pathway.
Scheme 40: Coupling reaction of α-azidoketones.
Scheme 41: Probable pathway.
Scheme 42: Probable mechanism with free energy calculations.
Scheme 43: MCR for cyanated IP synthesis.
Scheme 44: Substrate scope for the reaction.
Scheme 45: Reaction mechanism.
Scheme 46: Probable mechanistic pathway for Cu/ZnAl2O4-catalyzed reaction.
Scheme 47: Copper-catalyzed double oxidative C–H amination reaction.
Scheme 48: Application towards different coupling reactions.
Scheme 49: Reaction mechanism.
Scheme 50: Condensation–cyclization approach for the synthesis of 1,3-diarylated imidazo[1,5-a]pyridines.
Scheme 51: Optimized reaction conditions.
Scheme 52: One-pot 2-CR.
Scheme 53: One-pot 3-CR without the isolation of chalcone.
Scheme 54: Copper–Pybox-catalyzed cyclization reaction.
Scheme 55: Mechanistic pathway catalyzed by Cu–Pybox complex.
Scheme 56: Cu(II)-promoted C(sp3)-H amination reaction.
Scheme 57: Wider substrate applicability for the reaction.
Scheme 58: Plausible reaction mechanism.
Scheme 59: CuI assisted C–N cross-coupling reaction.
Scheme 60: Probable reaction mechanism involving sp3 C–H amination.
Scheme 61: One-pot MCR-catalyzed by CoFe2O4/CNT-Cu.
Scheme 62: Mechanistic pathway.
Scheme 63: Synthetic scheme for 3-nitroimidazo[1,2-a]pyridines.
Scheme 64: Plausible mechanism for CuBr-catalyzed reaction.
Scheme 65: Regioselective synthesis of halo-substituted imidazo[1,2-a]pyridines.
Scheme 66: Synthesis of 2-phenylimidazo[1,2-a]pyridines.
Scheme 67: Synthesis of diarylated compounds.
Scheme 68: CuBr2-mediated one-pot two-component oxidative coupling reaction.
Scheme 69: Decarboxylative cyclization route to synthesize 1,3-diarylimidazo[1,5-a]pyridines.
Scheme 70: Mechanistic pathway.
Scheme 71: C–H functionalization reaction of enamines to produce diversified heterocycles.
Scheme 72: A plausible mechanism.
Scheme 73: CuI-promoted aerobic oxidative cyclization reaction of ketoxime acetates and pyridines.
Scheme 74: CuI-catalyzed pathway for the formation of imidazo[1,2-a]pyridine.
Scheme 75: Mechanistic pathway.
Scheme 76: Mechanistic rationale for the synthesis of products.
Scheme 77: Copper-catalyzed synthesis of vinyloxy-IP.
Scheme 78: Regioselective product formation with propiolates.
Scheme 79: Proposed mechanism for vinyloxy-IP formation.
Scheme 80: Regioselective synthesis of 3-hetero-substituted imidazo[1,2-a]pyridines with different reaction su...
Scheme 81: Mechanistic pathway.
Scheme 82: CuI-mediated synthesis of 3-formylimidazo[1,2-a]pyridines.
Scheme 83: Radical pathway for 3-formylated IP synthesis.
Scheme 84: Pd-catalyzed urea-cyclization reaction for IPs.
Scheme 85: Pd-catalyzed one-pot-tandem amination and intramolecular amidation reaction.
Figure 5: Scope of aniline nucleophiles.
Scheme 86: Pd–Cu-catalyzed Sonogashira coupling reaction.
Scheme 87: One-pot amide coupling reaction for the synthesis of imidazo[4,5-b]pyridines.
Scheme 88: Urea cyclization reaction for the synthesis of two series of pyridines.
Scheme 89: Amidation reaction for the synthesis of imidazo[4,5-b]pyridines.
Figure 6: Amide scope.
Scheme 90: Pd NPs-catalyzed 3-component reaction for the synthesis of 2,3-diarylated IPs.
Scheme 91: Plausible mechanistic pathway for Pd NPs-catalyzed MCR.
Scheme 92: Synthesis of chromenoannulated imidazo[1,2-a]pyridines.
Scheme 93: Mechanism for the synthesis of chromeno-annulated IPs.
Scheme 94: Zinc oxide NRs-catalyzed synthesis of imidazo[1,2-a]azines/diazines.
Scheme 95: Zinc oxide-catalyzed isocyanide based GBB reaction.
Scheme 96: Reaction pathway for ZnO-catalyzed GBB reaction.
Scheme 97: Mechanistic pathway.
Scheme 98: ZnO NRs-catalyzed MCR for the synthesis of imidazo[1,2-a]azines.
Scheme 99: Ugi type GBB three-component reaction.
Scheme 100: Magnetic NPs-catalyzed synthesis of imidazo[1,2-a]pyridines.
Scheme 101: Regioselective synthesis of 2-alkoxyimidazo[1,2-a]pyridines catalyzed by Fe-SBA-15.
Scheme 102: Plausible mechanistic pathway for the synthesis of 2-alkoxyimidazopyridine.
Scheme 103: Iron-catalyzed synthetic approach.
Scheme 104: Iron-catalyzed aminooxygenation reaction.
Scheme 105: Mechanistic pathway.
Scheme 106: Rh(III)-catalyzed double C–H activation of 2-substituted imidazoles and alkynes.
Scheme 107: Plausible reaction mechanism.
Scheme 108: Rh(III)-catalyzed non-aromatic C(sp2)–H bond activation–functionalization for the synthesis of imid...
Scheme 109: Reactivity and selectivity of different substrates.
Scheme 110: Rh-catalyzed direct C–H alkynylation by Li et al.
Scheme 111: Suggested radical mechanism.
Scheme 112: Scandium(III)triflate-catalyzed one-pot reaction and its mechanism for the synthesis of benzimidazo...
Scheme 113: RuCl3-assisted Ugi-type Groebke–Blackburn condensation reaction.
Scheme 114: C-3 aroylation via Ru-catalyzed two-component reaction.
Scheme 115: Regioselective synthetic mechanism.
Scheme 116: La(III)-catalyzed one-pot GBB reaction.
Scheme 117: Mechanistic approach for the synthesis of imidazo[1,2-a]pyridines.
Scheme 118: Synthesis of imidazo[1,2-a]pyridine using LaMnO3 NPs under neat conditions.
Scheme 119: Mechanistic approach.
Scheme 120: One-pot 3-CR for regioselective synthesis of 2-alkoxy-3-arylimidazo[1,2-a]pyridines.
Scheme 121: Formation of two possible products under optimization of the catalysts.
Scheme 122: Mechanistic strategy for NiFe2O4-catalyzed reaction.
Scheme 123: Two-component reaction for synthesizing imidazodipyridiniums.
Scheme 124: Mechanistic scheme for the synthesis of imidazodipyridiniums.
Scheme 125: CuI-catalyzed arylation of imidazo[1,2-a]pyridines.
Scheme 126: Mechanism for arylation reaction.
Scheme 127: Cupric acetate-catalyzed double carbonylation approach.
Scheme 128: Radical mechanism for double carbonylation of IP.
Scheme 129: C–S bond formation reaction catalyzed by cupric acetate.
Scheme 130: Cupric acetate-catalyzed C-3 formylation approach.
Scheme 131: Control experiments for signifying the role of DMSO and oxygen.
Scheme 132: Mechanism pathway.
Scheme 133: Copper bromide-catalyzed CDC reaction.
Scheme 134: Extension of the substrate scope.
Scheme 135: Plausible radical pathway.
Scheme 136: Transannulation reaction for the synthesis of imidazo[1,5-a]pyridines.
Scheme 137: Plausible reaction pathway for denitrogenative transannulation.
Scheme 138: Cupric acetate-catalyzed C-3 carbonylation reaction.
Scheme 139: Plausible mechanism for regioselective C-3 carbonylation.
Scheme 140: Alkynylation reaction at C-2 of 3H-imidazo[4,5-b]pyridines.
Scheme 141: Two-way mechanism for C-2 alkynylation of 3H-imidazo[4,5-b]pyridines.
Scheme 142: Palladium-catalyzed SCCR approach.
Scheme 143: Palladium-catalyzed Suzuki coupling reaction.
Scheme 144: Reaction mechanism.
Scheme 145: A phosphine free palladium-catalyzed synthesis of C-3 arylated imidazopyridines.
Scheme 146: Palladium-mediated Buchwald–Hartwig cross-coupling reaction.
Figure 7: Structure of the ligands optimized.
Scheme 147: Palladium acetate-catalyzed direct arylation of imidazo[1,2-a]pyridines.
Scheme 148: Palladium acetate-catalyzed mechanistic pathway.
Scheme 149: Palladium acetate-catalyzed regioselective arylation reported by Liu and Zhan.
Scheme 150: Mechanism for selective C-3 arylation of IP.
Scheme 151: Pd(II)-catalyzed alkenylation reaction with styrenes.
Scheme 152: Pd(II)-catalyzed alkenylation reaction with acrylates.
Scheme 153: A two way mechanism.
Scheme 154: Double C–H activation reaction catalyzed by Pd(OAc)2.
Scheme 155: Probable mechanism.
Scheme 156: Palladium-catalyzed decarboxylative coupling.
Scheme 157: Mechanistic cycle for decarboxylative arylation reaction.
Scheme 158: Ligand-free approach for arylation of imidazo[1,2-a]pyridine-3-carboxylic acids.
Scheme 159: Mechanism for ligandless arylation reaction.
Scheme 160: NHC-Pd(II) complex assisted arylation reaction.
Scheme 161: C-3 arylation of imidazo[1,2-a]pyridines with aryl bromides catalyzed by Pd(OAc)2.
Scheme 162: Pd(II)-catalyzed C-3 arylations with aryl tosylates and mesylates.
Scheme 163: CDC reaction for the synthesis of imidazo[1,2-a]pyridines.
Scheme 164: Plausible reaction mechanism for Pd(OAc)2-catalyzed synthesis of imidazo[1,2-a]pyridines.
Scheme 165: Pd-catalyzed C–H amination reaction.
Scheme 166: Mechanism for C–H amination reaction.
Scheme 167: One-pot synthesis for 3,6-di- or 2,3,6-tri(hetero)arylimidazo[1,2-a]pyridines.
Scheme 168: C–H/C–H cross-coupling reaction of IPs and azoles catalyzed by Pd(II).
Scheme 169: Mechanistic cycle.
Scheme 170: Rh-catalyzed C–H arylation reaction.
Scheme 171: Mechanistic pathway for C–H arylation of imidazo[1,2-a]pyridine.
Scheme 172: Rh(III)-catalyzed double C–H activation of 2-phenylimidazo[1,2-a]pyridines and alkynes.
Scheme 173: Rh(III)-catalyzed mechanistic pathway.
Scheme 174: Rh(III)-mediated oxidative coupling reaction.
Scheme 175: Reactions showing functionalization of the product obtained by the group of Kotla.
Scheme 176: Mechanism for Rh(III)-catalyzed oxidative coupling reaction.
Scheme 177: Rh(III)-catalyzed C–H activation reaction.
Scheme 178: Mechanistic cycle.
Scheme 179: Annulation reactions of 2-arylimidazo[1,2-a]pyridines and alkynes.
Scheme 180: Two-way reaction mechanism for annulations reaction.
Scheme 181: [RuCl2(p-cymene)]2-catalyzed C–C bond formation reaction.
Scheme 182: Reported reaction mechanism.
Scheme 183: Fe(III) catalyzed C-3 formylation approach.
Scheme 184: SET mechanism-catalyzed by Fe(III).
Scheme 185: Ni(dpp)Cl2-catalyzed KTC coupling.
Scheme 186: Pd-catalyzed SM coupling.
Scheme 187: Vanadium-catalyzed coupling of IP and NMO.
Scheme 188: Mechanistic cycle.
Scheme 189: Selective C3/C5–H bond functionalizations by mono and bimetallic systems.
Scheme 190: rGO-Ni@Pd-catalyzed C–H bond arylation of imidazo[1,2-a]pyridine.
Scheme 191: Mechanistic pathway for heterogeneously catalyzed arylation reaction.
Scheme 192: Zinc triflate-catalyzed coupling reaction of substituted propargyl alcohols.
Remarkable effect of alkynyl substituents on the fluorescence properties of a BN-phenanthrene
- Alberto Abengózar,
- David Sucunza,
- Patricia García-García and
- Juan J. Vaquero
Beilstein J. Org. Chem. 2019, 15, 1257–1261, doi:10.3762/bjoc.15.122
- -aromatics. Interestingly, 1a turned out to be weakly fluorescent [23], in contrast to other BN-phenanthrene isomers described previously [25][26]. The presence of aryl or amino substituents at C1, which can be introduced via bromination and subsequent palladium-catalyzed cross coupling, does not have a
- -phenanthrene 1a and the derivatives prepared in this work are shown in Figure 2. 1-(Phenylethynyl)-4a-aza-10a-boraphenanthrene (5), which was previously prepared in our group by bromination of 1a and subsequent coupling [23], was also included in this comparative study. The absorption and emission data for
Graphical Abstract
Figure 1: BN-phenanthrene 1a and synthesis of substituted derivatives proposed in this work.
Scheme 1: Synthesis of Cl-substituted BN-phenanthrene 1b.
Scheme 2: Palladium-catalyzed cross-couplings of Cl-substituted BN-phenanthrene 1b.
Scheme 3: Pd-catalyzed Sonogashira reactions of Cl-substituted BN-phenanthrene 1b.
Figure 2: UV–vis absorption (top) and emission (bottom) spectra for BN-phenanthrenes 1 and 5 in cyclohexane (...
Figure 3: Solutions of 1a–f and 5 (from left to right) under UV irradiation.
Coordination chemistry and photoswitching of dinuclear macrocyclic cadmium-, nickel-, and zinc complexes containing azobenzene carboxylato co-ligands
- Jennifer Klose,
- Tobias Severin,
- Peter Hahn,
- Alexander Jeremies,
- Jens Bergmann,
- Daniel Fuhrmann,
- Jan Griebel,
- Bernd Abel and
- Berthold Kersting
Beilstein J. Org. Chem. 2019, 15, 840–851, doi:10.3762/bjoc.15.81
- drastically alter its structural properties and reactivities. Prominent examples are the cis-bromination of α,β-unsaturated carboxylato ligands [2], regioselective Diels–Alder reactions of encapsulated dienoate ligands [3], and the stabilization of unusual co-ligand conformations, respectively [4]. The
Graphical Abstract
Figure 1: Left: Mixed ligand complexes of the type [M2L(μ-L')]n+ supported by the macrocyclic ligand H2L (M =...
Figure 2: Synthesized compounds and their labels.
Scheme 1: Synthesis of complexes 1–9.
Figure 3: 1H NMR spectrum of 6 in CD3CN at 295 K (1.0–8.0 ppm). The resonances and assignments are listed in Table 2...
Figure 4: Structure of the [Zn2L(μ-azo-OH)]+ cation in crystals of [Zn2L(μ-azo-OH)][Zn2L(μ-azo-O)]·4MeCN·3H2O...
Figure 5: Space filling representation of the packing of two symmetry-related [Zn2L(μ-azo-NMe2)]+ cations in ...
Figure 6: Structure of the [Cd2L(μ-azo-NMe2)]+ cation in crystals of [Cd2L(μ-azo-NMe2)]ClO4·0.5MeOH (6·0.5MeO...
Figure 7: Space filling representation of the packing of four [Cd2L(μ-azo-NMe2)]+ cations in crystals of 6·0....
Figure 8: Structures of the two crystallographically independent [Ni2L(μ-azo-NMe2)]+ cations A (left) and B (...
Figure 9: Left: ORTEP representation of the molecular structure of the [Cd2L(μ-azo-CO2Me)]+ cation in crystal...
Figure 10: Plots of the effective magnetic moment μeff for 2 (open circles), 4 (open squares), and 7 (open tri...
Figure 11: UV–vis spectra of Hazo-H (red line), [Cd2L(μ-Cl)](ClO4) (black line) and [Cd2L(μ-azo-H)]ClO4 (1, bl...
Figure 12: UV–vis spectra of Hazo-NMe2 (red line), [Ni2L(μ-Cl)](ClO4) (black line) and [Ni2L(μ-azo-NMe2)]ClO4 (...
Figure 13: UV–vis spectra of solutions of [Cd2L(μ-azo-H)]ClO4 (1) in acetonitrile irradiated with a UV LED lam...
Scheme 2: Cis/trans isomerization process of the bound azo-carboxylato co-ligand in [Cd2L(μ-azo-H)]ClO4 (1) i...
Synthesis of polydicyclopentadiene using the Cp2TiCl2/Et2AlCl catalytic system and thin-layer oxidation of the polymer in air
- Zhargolma B. Bazarova,
- Ludmila S. Soroka,
- Alex A. Lyapkov,
- Мekhman S. Yusubov and
- Francis Verpoort
Beilstein J. Org. Chem. 2019, 15, 733–745, doi:10.3762/bjoc.15.69
- located on the surface of the polymer are capable of various addition reactions (bromination, epoxidation, oxidation) forming films of several tens or hundreds of nanometers thick on the surface. However, no further penetration of reactants into the deeper polydicyclopentadiene layers occurs [28]. It is
Graphical Abstract
Figure 1: Absorption spectra in the UV and visible spectral region: 1) bis(cyclopentadienyl)titan dichloride (...
Figure 2: Absorption spectra in the visible spectral region: 1) Cp2TiCl2·AlEt2Cl (toluene, 10 mmol/L, Ti/Al r...
Figure 3: 1Н NMR spectra of tricyclopentadiene (a) and the interaction product between Cp2TiCl2 and AlEt2Cl w...
Scheme 1: Mechanism of alkylation of Cp2TiCl2.
Figure 4: Visible spectra of a mixture of Cp2TiCl2 and AlEt2Cl as function of time.
Figure 5: Thermometric curve of DCPD polymerization using the catalyst system based on Cp2TiCl2 (a) and its s...
Scheme 2: The structures formed as a result of the cationic polymerization of dicyclopentadiene.
Scheme 3: The units resulting from ROMP of dicyclopentadiene.
Scheme 4: Mechanism of ROMP dicyclopentadiene.
Figure 6: FTIR spectrum of PDCPD obtained in toluene with the catalyst system based on Cp2TiCl2 and AlEt2Cl.
Figure 7: 1Н NMR spectrum of PDCPD obtained with the catalytic system based on Cp2TiCl2 and AlEt2Cl.
Figure 8: GPC traces for two samples of DCPD polymers obtained at a concentration of Cp2TiCl2/AlEt2Cl complex...
Figure 9: IR spectra of cationic polymerized dicyclopentadiene taken after certain periods of time exposed to...
Figure 10: Correlation of intensities of vibrational bands at 1620 and 700 cm−1 and layer exposure time in air...
Figure 11: DSC exotherm for PDCPD subjected to air oxidation for 700 hours.
Figure 12: DSC exotherm for PDCPD subjected to unexposed film: 1) in air atmosphere; 2) in argon.
Scheme 5: Possible radical formation in the reaction (1).
Scheme 6: The first step of the chain propagation.
Figure 13: Dependence of intensities of adsorption bands at 1410 and 700 cm−1 and dwell time of the layer in a...
Figure 14: Semi-logarithmic kinetic curve of PDCPD oxidation in air (thin layer on silicon) with respect to in...
Figure 15: The distribution of oxygen concentration in the polymer layer: 1 – a layer of oxidized cross-linked...
Figure 16: Dependence of the ratio of adsorption bands at 1700 and 700 cm−1 on the exposure time of the layer ...
Figure 17: Infrared spectra (a) of products of cationic polymerization of DCPD, stabilized with an antioxidant...
Efficient synthesis of 4-substituted-ortho-phthalaldehyde analogues: toward the emergence of new building blocks
- Clémence Moitessier,
- Ahmad Rifai,
- Pierre-Edouard Danjou,
- Isabelle Mallard and
- Francine Cazier-Dennin
Beilstein J. Org. Chem. 2019, 15, 721–726, doi:10.3762/bjoc.15.67
- , rarely recorded in the literature with an efficient synthetic pathway; conjointly to the 3-substituted OPA that is even less described. In 1966, Khan et al. presented the synthesis of 4-hydroxy and 4-methoxy-ortho-phthalaldehyde (4-HO-OPA and 4-MeO-OPA) by bromination and oxidation of 4-hydroxy and 4
Graphical Abstract
Scheme 1: Synthesis of 4,5-dihydroisobenzofuran-5-ol (3).
Scheme 2: Protection strategy of 4,5-dihydroisobenzofuran-5-ol (3).
Scheme 3: Oxidation of 5-substituted-4,5-dihydroisobenzofuran-5-ol in presence of SeO2 or DDQ.
Scheme 4: Synthesis of 4-hydroxy-ortho-phthalaldehyde (6) through MAOS demethylation of 4-methoxy-ortho-phtha...
Synthesis of 2H-furo[2,3-c]pyrazole ring systems through silver(I) ion-mediated ring-closure reaction
- Vaida Milišiūnaitė,
- Rūta Paulavičiūtė,
- Eglė Arbačiauskienė,
- Vytas Martynaitis,
- Wolfgang Holzer and
- Algirdas Šačkus
Beilstein J. Org. Chem. 2019, 15, 679–684, doi:10.3762/bjoc.15.62
- -trisubstituted 2H-furo[2,3-c]pyrazole-5-carboxylic acids and related carboxamides [11][12]. The aforementioned carboxylic acids have been prepared by bromination of the corresponding pyrano[2,3-c]pyrazol-6(1H)-one derivatives followed by heating of the obtained 5-bromo derivatives in the presence of sodium
Graphical Abstract
Scheme 1: Preparation of hydroxyalkynyl substrates from 1-phenyl-1H-pyrazol-3-ol (1).
Scheme 2: Cyclization of hydroxyalkynyl substrates to 2,5-disubstituted 2H-furo[2,3-c]pyrazoles.
Figure 1: a) ORTEP diagram of the asymmetric unit consisting of two independent molecules 4d(A) and 4d(B); b)...
Low-budget 3D-printed equipment for continuous flow reactions
- Jochen M. Neumaier,
- Amiera Madani,
- Thomas Klein and
- Thomas Ziegler
Beilstein J. Org. Chem. 2019, 15, 558–566, doi:10.3762/bjoc.15.50
- reagent (Ag2CO3 on Celite) [36][37]. The bromination and glycosylation reaction steps had to be performed in separate reactions. Therefore, we also investigated glycosylations with the respective imidate glycosyl donor 5. First, the cleavage of the anomeric acetyl group with hydrazine acetate was
Graphical Abstract
Figure 1: a) CAD drawing of the reactor R1. b) 3D-printed reactor R1 from the CAD drawing. The reactor is fil...
Figure 2: a) L-shaped rail made of PLA with the mounted reactor R3. The small picture shows the fixed reactor...
Figure 3: a) Microreactor R4 with a reactor volume of 12 µL filled with a blue dye solution. b) Magnification...
Figure 4: CAD drawing of two CSTR with three (a) and two inlets (b) with in-printed screw nuts 1/4’’ – 28 thr...
Figure 5: a) Unassembled parts used for one syringe pump. b) Assembled pump with controller.
Scheme 1: Preparation of acetobromo-α-D-glucose 2.
Figure 6: a) Schematic diagram for the continuous-flow synthesis of acetobromo-α-D-glucose 2. b) Photograph o...
Scheme 2: Flow Koenigs–Knorr reaction to methyl glycoside 3 with silver triflate.
Scheme 3: Preparation of glycosyl donor 5.
Scheme 4: Two-step glycosylation reactions starting from pyranose 3.
Scheme 5: Synthesis of azide-functionalized glycopyranoside 8.
Syntheses and chemical properties of β-nicotinamide riboside and its analogues and derivatives
- Mikhail V. Makarov and
- Marie E. Migaud
Beilstein J. Org. Chem. 2019, 15, 401–430, doi:10.3762/bjoc.15.36
- + chemistry. Finally, Lee et al. [27] studied in detail the regiochemical outcomes of the synthesis of the bromosugars 7a and 7b of the glycosylation of Nam (1a) with these bromosugars as well as the deprotection of the acylated nucleosides 8a,b. It was observed that the bromination of 2a with HBr gas in
- β/α mixture was obtained when 2a was reacted with neat bromotrimethylsilane at room temperature. Bromination of 2b yielded a 10:1 β/α mixture of the anomeric bromide 7b [27]. The reaction between Nam (1a) and the bromide 7a was carried out in liquid SO2 and proceeded in high yields with the
Graphical Abstract
Figure 1: Structural formulas of Nam, NA, NR+, NMN, and NAD+.
Figure 2: Main synthetic routes to nicotinamide riboside (NR+X−).
Scheme 1: Synthesis of NR+Cl− based on the reaction of peracylated chlorosugars with Nam.
Figure 3: Predominant formation of β-anomer over α-anomer of NR+X−.
Scheme 2: Synthesis of NR+Cl− by reacting 3,5-di-O-benzoyl-D-ribofuranosyl chloride (5) with Nam (1a).
Figure 4: Mechanism of the formation of the β-anomer of the glycosylated product in the case of the reaction ...
Scheme 3: Synthesis of NR+Br− by reacting bromosugars with Nam (1a).
Scheme 4: Synthesis of NR+OTf− based on the glycosylation of Nam (1a) with tetra-O-acetyl-β-D-ribofuranose (2a...
Scheme 5: Improved synthesis of NR+OTfˉ and NAR+OTfˉ based on the glycosylation of pre-silylated Nam or NA wi...
Scheme 6: Synthesis of triacetylated NAR+OTf− by glycosylation of nicotinic acid trimethylsilyl ester with te...
Scheme 7: Synthesis of NR+Cl− from NR+OTf− by means of ion exchange with sodium chloride solution.
Scheme 8: Synthesis of acylated NR+OTf− by means of ion exchange with sodium chloride.
Scheme 9: Synthesis of triacetylated derivatives of NAR+ by glycosylation of nicotinic acid esters with ribos...
Scheme 10: Synthesis of NR+OTf− from the triflate salt of ethyl nicotinate-2,3,5-triacetyl-β-D-riboside in met...
Scheme 11: Reaction of 2,3,5-tri-O-acetyl-β-phenyl nicotinate riboside triflate salt with secondary and tertia...
Scheme 12: Synthesis of NMN based on the Zincke reaction of N-(2,4-dinitrophenyl)-3-carbamoylpyridinium chlori...
Scheme 13: Synthesis of NMN based on the Zincke reaction of N-(2,4-dinitrophenyl)-3-carbamoylpyridinium chlori...
Scheme 14: Efficacious protection of 2′,3′-hydroxy groups of NR+X−.
Scheme 15: Protection of the 2′,3′-hydroxy groups of NR+Cl– with a mesitylmethylene acetal group.
Figure 5: Reduction of derivatives of NR+Xˉ into corresponding 1,2-; 1,4-; 1,6-NRH derivatives.
Figure 6: Mechanism of the reduction of the pyridinium core with dithionite as adapted from [67].
Scheme 16: Reduction of triacylated NR+OTf– derivatives by sodium dithionite followed by complete removal of a...
Figure 7: Structural formulas of iridium and rhodium catalysts (a)–(d) for regeneration of NAD(P)H from NAD(P)...
Figure 8: Two approaches to synthesis of 5′-derivatives of NR+.
Scheme 17: Synthesis of NMN starting from NR+ salt.
Scheme 18: Efficient synthesis of NMN by phosphorylation of 2′,3′-O-isopropylidene-NR+ triflate followed by re...
Scheme 19: Synthesis of a bisphosphonate analogue of β-NAD+ based on DCC-induced conjugation of 2′,3′-O-isopro...
Scheme 20: Synthesis of 5′-acyl and 2′,3′,5′-triacyl derivatives of NR+.
Figure 9: Structural formulas of NMN analogues 39–41.
Scheme 21: Synthesis of 5′-phosphorylated derivatives of NR+ using a “reduction–modification–oxidation” approa...
Scheme 22: Synthesis of 5′-phosphorylated derivatives of NR+ using a “reduction–modification–reoxidation” appr...
Figure 10: Structural formulas of 5′-phosphorylated derivatives of NR+.
Scheme 23: Synthesis of 5′-phosphorylated derivatives of NR+ using a direct NR+ phosphorylation approach.
Figure 11: Structural formulas of amino acid NR+ conjugates.
Scheme 24: Synthesis of amino acid NR+ conjugates using NRH and protected amino acid under CDI-coupling condit...
Figure 12: Chemical structures of known isotopically labelled NR+ analogues and derivatives.
Scheme 25: Synthesis of [2′-3H]-NR+ and [2′-3H]-NMN.
Scheme 26: Synthesis of α- and β-anomers of [1′-2H]-NMN.
Oxidative radical ring-opening/cyclization of cyclopropane derivatives
- Yu Liu,
- Qiao-Lin Wang,
- Zan Chen,
- Cong-Shan Zhou,
- Bi-Quan Xiong,
- Pan-Liang Zhang,
- Chang-An Yang and
- Quan Zhou
Beilstein J. Org. Chem. 2019, 15, 256–278, doi:10.3762/bjoc.15.23
- carried out with inexpensive reagents and can also be applied to the distal bromination of cycloalkanols. The possible mechanism is outlined in Scheme 28. The cycloalkoxy radical 98 is generated from cyclopropanol 91 under the action of the metastable Ag(II) species, which is formed by the interaction of
Graphical Abstract
Scheme 1: The oxidative radical ring-opening/cyclization of cyclopropane derivatives.
Scheme 2: Mn(OAc)3-mediated oxidative radical ring-opening and cyclization of MCPs with malonates.
Scheme 3: Mn(III)-mediated oxidative radical ring-opening and cyclization of MCPs with 1,3-dicarbonyl compoun...
Scheme 4: Heat-promoted ring-opening/cyclization of MCPs with elemental chalgogens.
Scheme 5: Copper(II) acetate-mediated oxidative radical ring-opening and cyclization of MCPs with diphenyl di...
Scheme 6: AIBN-promoted oxidative radical ring-opening and cyclization of MCPs with benzenethiol.
Scheme 7: AIBN-mediated oxidative radical ring-opening and cyclization of MCPs with diethyl phosphites.
Scheme 8: Organic-selenium induced radical ring-opening and cyclization of MCPs derivatives (cyclopropylaldeh...
Scheme 9: Copper(I)-catalyzed oxidative radical trifluoromethylation/ring-opening/cyclization of MCPs with To...
Scheme 10: Ag(I)-mediated trifluoromethylthiolation/ring-opening/cyclization of MCPs with AgSCF3.
Scheme 11: oxidative radical ring-opening and cyclization of MCPs with α-C(sp3)-–H of ethers.
Scheme 12: Oxidative radical ring-opening and cyclization of MCPs with aldehydes.
Scheme 13: Cu(I) or Fe(II)-catalyzed oxidative radical trifluoromethylation/ring-opening/cyclization of MCPs d...
Scheme 14: Rh(II)-catalyzed oxidative radical ring-opening and cyclization of MCPs.
Scheme 15: Ag(I)-catalyzed oxidative radical amination/ring-opening/cyclization of MCPs derivatives.
Scheme 16: Heating-promoted radical ring-opening and cyclization of MCP derivatives (arylvinylidenecyclopropan...
Scheme 17: Bromine radical-mediated ring-opening of alkylidenecyclopropanes.
Scheme 18: Fluoroalkyl (Rf) radical-mediated ring-opening of MCPs.
Scheme 19: Visible-light-induced alkylation/ring-opening/cyclization of cyclopropyl olefins with bromides.
Scheme 20: Mn(III)-mediated ring-opening and [3 + 3]-annulation of cyclopropanols and vinyl azides.
Scheme 21: Ag(I)-catalyzed oxidative ring-opening of cyclopropanols with quinones.
Scheme 22: Ag(I)-catalyzed oxidative ring-opening of cyclopropanols with heteroarenes.
Scheme 23: Cu(I)-catalyzed oxidative ring-opening/trifluoromethylation of cyclopropanols.
Scheme 24: Cu(I)-catalyzed oxidative ring-opening and trifluoromethylation/trifluoromethylthiolation of cyclop...
Scheme 25: Ag(I)-mediated oxidative ring-opening/fluorination of cyclopropanols with Selectfluor.
Scheme 26: Photocatalyzed ring-opening/fluorination of cyclopropanols with Selectfluor.
Scheme 27: Na2S2O8-promoted ring-opening/alkynylation of cyclopropanols with EBX.
Scheme 28: Ag(I)-catalyzed ring-opening and chlorination of cyclopropanols with aldehydes.
Scheme 29: Ag(I)-catalyzed ring-opening/alkynylation of cyclopropanols with EBX.
Scheme 30: Na2S2O8-promoted ring-opening/alkylation of cyclopropanols with acrylamides.
Scheme 31: Cyclopropanol ring-opening initiated tandem cyclization with acrylamides or 2-isocyanobiphenyls.
Scheme 32: Ag(II)-mediated oxidative ring-opening/fluorination of cyclopropanols with AgF2.
Scheme 33: Cu(II)-catalyzed ring-opening/fluoromethylation of cyclopropanols with sulfinate salts.
Scheme 34: Cu(II)-catalyzed ring-opening/sulfonylation of cyclopropanols with sulfinate salts.
Scheme 35: Na2S2O8-promoted ring-opening/arylation of cyclopropanols with propiolamides.
Scheme 36: The ring-opening and [3 + 2]-annulation of cyclopropanols with α,β-unsaturated aldehydes.
Scheme 37: Cu(II)-catalyzed ring-opening/arylation of cyclopropanols with aromatic nitrogen heterocyles.
Scheme 38: Ag(I)-catalyzed ring-opening and difluoromethylthiolation of cyclopropanols with PhSO2SCF2H.
Scheme 39: Ag(I)-catalyzed ring-opening and acylation of cyclopropanols with aldehydes.
Scheme 40: Aerobic oxidation ring-opening of cyclopropanols for the synthesis of 2-oxyranyl ketones.
Scheme 41: Aerobic oxidation ring-opening of cyclopropanols for the synthesis of linear enones.
Scheme 42: Aerobic oxidation ring-opening of cyclopropanols for the synthesis of metabolite.
Synthesis of nonracemic hydroxyglutamic acids
- Dorota G. Piotrowska,
- Iwona E. Głowacka,
- Andrzej E. Wróblewski and
- Liwia Lubowiecka
Beilstein J. Org. Chem. 2019, 15, 236–255, doi:10.3762/bjoc.15.22
- -hydroxy-L-glutamic acid derivative 66 (Scheme 16) was required and it was obtained as a single diastereoisomer from 65 in the same way [75][76]. By bromination of L-glutamic acid Bromination of N-phthaloyl-L-glutamic acid [(S)-67] followed by methanolysis gave a 2:1 mixture of threo and erythro
Graphical Abstract
Figure 1: Structure of L-glutamic acid.
Figure 2: 3-Hydroxy- (2), 4-hydroxy- (3) and 3,4-dihydroxyglutamic acids (4).
Figure 3: Enantiomers of 3-hydroxyglutamic acid (2).
Scheme 1: Synthesis of (2S,3R)-2 from (R)-Garner's aldehyde. Reagents and conditions: a) MeOCH=CH–CH(OTMS)=CH2...
Scheme 2: Synthesis of (2S,3R)-2 and (2S,3S)-2 from (R)-Garner’s aldehyde. Reagents and conditions: a) H2C=CH...
Scheme 3: Two-carbon homologation of the protected L-serine. Reagents and conditions: a) Fmoc-succinimide, Na2...
Scheme 4: Synthesis of di-tert-butyl ester of (2R,3S)-2 from L-serine. Reagents and conditions: a) PhSO2Cl, K2...
Scheme 5: Synthesis of (2R,3S)-2 from O-benzyl-L-serine. Reagents and conditions: a) (CF3CH2O)2P(O)CH2COOMe, ...
Scheme 6: Synthesis of (2S,3R)-2 employing a one-pot cis-olefination–conjugate addition sequence. Reagents an...
Scheme 7: Synthesis of the orthogonally protected (2S,3R)-2 from a chiral aziridine. Reagents and conditions:...
Scheme 8: Synthesis of N-Boc-protected (2S,3R)-2 from D-phenylglycine. Reagents and conditions: a) BnMgCl, et...
Scheme 9: Synthesis of (2S,3R)-2 employing ketopinic acid as chiral auxiliary. Reagents and conditions: a) Br2...
Scheme 10: Synthesis of dimethyl ester of (2S,3R)-2 employing (1S)-2-exo-methoxyethoxyapocamphane-1-carboxylic...
Scheme 11: Synthesis of N-Boc-protected dimethyl ester of (2S,3R)-2 from (S)-N-(1-phenylethyl)thioacetamide. R...
Scheme 12: Synthesis of N-Boc-protected dimethyl ester of (2S,3R)-2 via Sharpless epoxidation. Reagents and co...
Scheme 13: Synthesis of (2S,3S)-2 from the imide 51. Reagents and conditions: a) NaBH4, MeOH/CH2Cl2; b) Ac2O, ...
Scheme 14: Synthesis of (2R,3S)-2 and (2S,3S)-2 from the acetolactam 55 (PMB = p-methoxybenzyl). Reagents and ...
Scheme 15: Synthesis of (2S,3R)-2 from D-glucose. Reagents and conditions: a) NaClO2, 30% H2O2, NaH2PO4, MeCN;...
Figure 4: Enantiomers of 3-hydroxyglutamic acid (3).
Scheme 16: Synthesis of (4S)-4-hydroxy-L-glutamic acid [(2S,4S)-3] by electrophilic hydroxylation. Reagents an...
Scheme 17: Synthesis of all stereoisomers of 4-hydroxyglutamic acid (3). Reagents and conditions: a) Br2, PBr5...
Scheme 18: Synthesis of the orthogonally protected 4-hydroxyglutamic acid (2S,4S)-73. Reagents and conditions:...
Scheme 19: Synthesis of (2S,4R)-4-acetyloxyglutamic acid as a component of a dipeptide. Reagents and condition...
Scheme 20: Synthesis of N-Boc-protected dimethyl esters of (2S,4R)- and (2S,4S)-3 from (2S,4R)-4-hydroxyprolin...
Scheme 21: Synthesis of orthogonally protected (2S,4S)-3 from (2S,4R)-4-hydroxyproline. Reagents and condition...
Scheme 22: Synthesis of the protected (4R)-4-hydroxy-L-pyroglutamic acid (2S,4R)-87 by electrophilic hydroxyla...
Figure 5: Enantiomers of 3,4-dihydroxy-L-glutamic acid (4).
Scheme 23: Synthesis of (2S,3S,4R)-4 from the epoxypyrrolidinone 88. Reagents and conditions: a) MeOH, THF, KC...
Scheme 24: Synthesis of (2S,3R,4R)-4 from the orthoester 92. Reagents and conditions: a) OsO4, NMO, acetone/wa...
Scheme 25: Synthesis of (2S,3S,4S)-4 from the aziridinolactone 95. Reagents and conditions: a) BnOH, BF3·OEt2,...
Scheme 26: Synthesis of (2S,3S,4R)-4 and (2R,3S,4R)-4 from cyclic imides 106. Reagents and conditions: a) NaBH4...
Scheme 27: Synthesis of (2R,3R,4R)-4 and (2S,3R,4R)-4 from the cyclic meso-imide 110. Reagents and conditions:...
Scheme 28: Synthesis of (2S,3S,4S)-4 from the protected serinal (R)-23. Reagents and conditions: a) Ph3P=CHCOO...
Scheme 29: Synthesis of (2S,3S,4S)-4 from O-benzyl-N-Boc-D-serine. Reagents and conditions: a) ClCOOiBu, TEA, ...
Scheme 30: Synthesis of (2S,3S,4R)-127 by enantioselective conjugate addition and asymmetric dihydroxylation. ...
Figure 6: Structures of selected compounds containing hydroxyglutamic motives (in blue).
Mechanistic studies of an L-proline-catalyzed pyridazine formation involving a Diels–Alder reaction with inverse electron demand
- Anne Schnell,
- J. Alexander Willms,
- S. Nozinovic and
- Marianne Engeser
Beilstein J. Org. Chem. 2019, 15, 30–43, doi:10.3762/bjoc.15.3
- procedure published by Liu et al. [56] and bromination to the new benzyl bromide 9 succeeded with tribromoisocyanuric acid (TBCA) as published by de Almeida et al. [57]. The final transformation of benzyl bromide 9 to triphenylphosphonium charge-tagged 4∙Br was performed with a slightly modified protocol
Graphical Abstract
Figure 1: Charge-tagged L-proline-derived catalyst 1∙Cl [18].
Scheme 1: Putative catalytic cycle [51] for the L-proline-catalyzed Diels–Alder reaction with inverse electron de...
Scheme 2: Synthesis of the charge-tagged tetrazine 4∙Br as a reactant for the proline-catalyzed Diels–Alder r...
Scheme 3: Reaction R1: L-proline-catalyzed reaction between 2 and acetone.
Figure 2: NMR monitoring of reaction R1 in deuterated DMSO (concentration of tetrazine 0.005 mmol/mL).
Scheme 4: Equilibrium of oxazolidinone and enamine formation.
Figure 3: a) ESI mass spectrum of reaction R1 after 26 min. b) ESIMS monitoring of reaction R1. To better vis...
Figure 4: ESI mass spectrum of reaction R1 with preformed I1 8 minutes after adding substrate 2.
Scheme 5: Reaction R2: L-proline-catalyzed reaction between charge-tagged substrate 4∙Br and acetone. The reg...
Figure 5: ESI mass spectrum of reaction R2 using a continuous-flow setup with a calculated reaction time of 8...
Figure 6: a) Reaction R2 after two hours (syringe setup). b) ESIMS monitoring of reaction R2. Signal intensit...
Scheme 6: Reaction R3: substrate 2, acetone and charge-tagged catalyst 1∙Cl.
Figure 7: ESI mass spectrum of reaction R3 at 60 °C after 1.5 h.
Scheme 7: General catalytic cycle for reactions R1–R3.
Figure 8: ESIMS monitoring of reaction R3. The plotted intensity values for each molecule are a sum of all co...
Figure 9: Isomeric forms in equilibrium: enamine [I3a]+, oxazolidinone [I3b]+ and iminium [I3c]+.
Figure 10: ESI(+) CID spectrum of mass-selected [I3]+ (m/z 353); collision energy voltage 1 V.
Figure 11: ESI(+) CID spectrum of mass selected [II3]+ (m/z 589); collision energy voltage 5 V.
Figure 12: ESI(+) CID spectrum of mass selected [III3]+ (m/z 561); collision energy voltage 10 V.
Enhanced single-isomer separation and pseudoenantiomer resolution of new primary rim heterobifunctionalized α-cyclodextrin derivatives
- Iveta Tichá,
- Gábor Benkovics,
- Milo Malanga and
- Jindřich Jindřich
Beilstein J. Org. Chem. 2018, 14, 2829–2837, doi:10.3762/bjoc.14.261
- regioisomers on the primary rim of homobifunctionalized diazido-α-CDs by selective substitution on the primary rim. Specifically, three positional regioisomers 6A,6B-, 6A,6C-, and 6A,6D-diazido-α-CDs were prepared via different intermediates (using sulfonylation with capping agents, bromination and tosylation
- prepared all possible regioisomers of primary rim-disubstituted α-CD derivatives using the most common CD intermediates by commonly used derivatization (bromination, tosylation and capping). The three positional isomers (AB, AC, AD) were separated by ad hoc-developed HPLC methods, and the regioisomeric
- ). On one hand, a direct bromination of α-CD was performed under Vilsmeier/Haack conditions (reaction 3, Scheme 2) with N-bromosuccinimide (NBS) and Ph3P in N,N-dimethylformamide (DMF). Previous studies have shown that this reaction is highly regioselective for the primary rim of CD [28]. After a fast
Graphical Abstract
Figure 1: Schematic representation of native α-CD (1) and top view of its primary rim with alphabetic clockwi...
Scheme 1: Synthesis of 6A,6X-diazido-α-CD derivatives 4 via 6A,6X-capped α-CDs 2 and 3 and their regioisomeri...
Scheme 2: Synthesis of 6A,6X- and 6A,6D-diazido-α-CDs via 6A,6X-dibromo-α-CD 5, 6A,6D-dibromo-α-CD 5d interme...
Scheme 3: Synthesis of 6A,6X-diazido-α-CDs via 6A,6X-ditosyl-α-CD intermediates 6 and their regioisomeric rat...
Figure 2: HPLC chromatograms of 6A,6X-diazido-α-CDs 4 of the reactions 1–5, with ACN/water gradient elution a...
Scheme 4: Synthesis of 6A-azido-6X-mesitylenesulfonyl-α-CD 8 and conversion into 6A,6X-diazido-α-CD 4.
Figure 3: HPLC chromatograms of reaction 7 with separated 6A-azido-α-CD 7 as starting material and regioisome...
Figure 4: HPLC chromatograms of 6A-azido-6X-mesitylenesulfonyl-α-CD 8 (reaction 6): a) analytical and b) prep...
Figure 5: 1H NMR spectrum of the AC regioisomer 8c as a mixture of pseudoenantiomers prepared through reactio...
Figure 6: 13C NMR spectrum of the AC regioisomer 8c as a mixture of pseudoenantiomers prepared through reacti...
Figure 7: HPLC–MS chromatogram with the separated pseudoenantiomers of 6A-azido-6B-mesitylenesulfonyl-α-CD 8b...
Synthesis of mono-functionalized S-diazocines via intramolecular Baeyer–Mills reactions
- Miriam Schehr,
- Daniel Hugenbusch,
- Tobias Moje,
- Christian Näther and
- Rainer Herges
Beilstein J. Org. Chem. 2018, 14, 2799–2804, doi:10.3762/bjoc.14.257
- benzyl bromides 8–11, which were commercially available or synthesized by radical bromination. The S-diazocines precursors 13–16 were then subjected to the intramolecular Baeyer–Mills reaction yielding the S-diazocines 1–4. In the first step the nitro group was reduced with zinc powder to the
Graphical Abstract
Figure 1: Cis–trans isomerization of mono-functionalized S-diazocines 1–5.
Scheme 1: Reaction conditions: i) MeCN, AIBN, NBS; ii) NaBH4, THF; #commercially available iii) BH3·THF compl...
Figure 2: UV spectra of the S-diazocine 4 in cis (black) and in trans (red) configuration after irradiation w...
Figure 3: Left: crystal structure of the iodo-functionalized S-diazocine 3. Right: crystal structure of the u...
Non-metal-templated approaches to bis(borane) derivatives of macrocyclic dibridgehead diphosphines via alkene metathesis
- Tobias Fiedler,
- Michał Barbasiewicz,
- Michael Stollenz and
- John A. Gladysz
Beilstein J. Org. Chem. 2018, 14, 2354–2365, doi:10.3762/bjoc.14.211
- (in,in/out,out)-2·2BH3 (2%). Four of these structures are verified by independent syntheses. Second, 1,14-tetradecanedioic acid is converted (reduction, bromination, Arbuzov reaction, LiAlH4) to H2P((CH2)14)PH2 (10; 76% overall yield). The reaction with H3B·SMe2 gives 10·2BH3, which is treated with n
Graphical Abstract
Scheme 1: Syntheses of gyroscope like platinum and rhodium complexes and dibridgehead diphosphines derived th...
Scheme 2: Synthesis and alkene metathesis of the monophosphorus precursor 1·BH3.
Figure 1: The 13C{1H} NMR spectra (CDCl3, 100 MHz) of in,out-2·2BH3, (in,in/out,out)-2·2BH3, 6·2BH3, and the ...
Scheme 3: Synthesis of the diphosphorus precursor 11·2BH3.
Scheme 4: Truncated approaches to the diphosphorus precursor 11·2BH3 from 10.
Scheme 5: Alkene metathesis of the diphosphorus precursor 11·2BH3.
Scheme 6: Schematic comparison of the key alkene metathesis steps in Scheme 2 and Scheme 5.
Scheme 7: Steps that set the in,in/out,out vs in,out stereochemistry of 2·2BH3 in Scheme 2 and Scheme 5.
Scheme 8: Another non-metal-templated approach to dibridgehead diphosphorus compounds.
Scheme 9: Previously synthesized dibridgehead diphosphine diboranes.
Scheme 10: Alkene metathesis of the tetraalkenyldiphosphine diborane 19·2BH3.
Recent advances in hypervalent iodine(III)-catalyzed functionalization of alkenes
- Xiang Li,
- Pinhong Chen and
- Guosheng Liu
Beilstein J. Org. Chem. 2018, 14, 1813–1825, doi:10.3762/bjoc.14.154
- -disubstituted-α-hydroxy-carboxylamides, was disclosed by Gulder and co-workers [76]. This catalytic system was applied to the bromination of alkenes by Gulder and co-workers. For example, the iodine(III)-catalyzed halocyclization of methacrylamide 68 generated the brominated oxindole 69 (Scheme 20) [77]. In
- ]. Oxyarylation of alkenes [71]. Asymmetric oxidative rearrangements of alkenes [72]. Bromolactonization of alkenes [75]. Bromination of alkenes [77][78]. Cooperative strategy for the carbonylation of alkenes [79]. Acknowledgements We are grateful for financial support from the National Nature Science Foundation
Graphical Abstract
Figure 1: The structures of hypervalent iodine (III) reagents [8].
Scheme 1: Hypervalent iodine(III)-catalyzed functionalization of alkenes.
Scheme 2: Catalytic sulfonyloxylactonization of alkenoic acids [43].
Scheme 3: Catalytic diacetoxylation of alkenes [46].
Scheme 4: Intramolecular asymmetric dioxygenation of alkenes [48,50].
Scheme 5: Intermolecular asymmetric diacetoxylation of styrenes [52].
Scheme 6: Diacetoxylation of alkenes with ester groups containing catalysts 17 [55].
Scheme 7: Intramolecular diamination of alkenes [56].
Scheme 8: Intramolecular asymmetric diamination of alkenes [57].
Scheme 9: Intermolecular asymmetric diamination of alkenes [58].
Scheme 10: Iodoarene-catalyzed aminofluorination of alkenes [60,61].
Scheme 11: Iodoarene-catalyzed aminofluorination of alkenes [62].
Scheme 12: Catalytic difluorination of alkenes with Selectfluor [63].
Scheme 13: Iodoarene-catalyzed 1,2-difluorination of alkenes [64].
Scheme 14: Iodoarene-catalyzed asymmetric fluorination of styrenes [64,65].
Scheme 15: Gem-difluorination of styrenes [67].
Scheme 16: Asymmetric gem-difluorination of cinnamic acid derivatives [68].
Scheme 17: Oxyarylation of alkenes [71].
Scheme 18: Asymmetric oxidative rearrangements of alkenes [72].
Scheme 19: Bromolactonization of alkenes [75].
Scheme 20: Bromination of alkenes [77,78].
Scheme 21: Cooperative strategy for the carbonylation of alkenes [79].
