Search for "sulfoxide" in Full Text gives 226 result(s) in Beilstein Journal of Organic Chemistry. Showing first 200.
Beilstein J. Org. Chem. 2021, 17, 589–621, doi:10.3762/bjoc.17.53
Graphical Abstract
Figure 1: Potential classification of plastic recycling processes. The area covered by the present review is ...
Figure 2: EG produced during glycolytic depolymerisation of PET using DEG + DPG as solvent and titanium(IV) n...
Scheme 1: Simplified representation of the conversion of 1,4-PBD to C16–C44 macrocycles using Ru metathesis c...
Figure 3: Main added-value monomers obtainable by catalytic depolymerisation of PET via chemolytic methods.
Scheme 2: Hydrogenolytic depolymerisation of PET by ruthenium complexes.
Scheme 3: Depolymerisation of PET via catalytic hydrosilylation by Ir(III) pincer complex.
Scheme 4: Catalytic hydrolysis (top) and methanolysis (bottom) reactions of PET.
Scheme 5: Depolymerisation of PET by glycolysis with ethylene glycol.
Figure 4: Glycolysis of PET: evolution of BHET yield over time, with and without zinc acetate catalyst (196 °...
Scheme 6: Potential activated complex for the glycolysis reaction of PET catalysed by metallated ILs and evol...
Scheme 7: One-pot, two-step process for PET repurposing via chemical recycling.
Scheme 8: Synthetic routes to PLA.
Scheme 9: Structures of the zinc molecular catalysts used for PLA-methanolysis in various works. a) See [265], b) ...
Scheme 10: Depolymerisation of PLLA by Zn–N-heterocyclic carbene complex.
Scheme 11: Salalen ligands.
Scheme 12: Catalytic hydrogenolysis of PLA.
Scheme 13: Catalytic hydrosilylation of PLA.
Scheme 14: Hydrogenative depolymerisation of PBT and PCL by molecular Ru catalysts.
Scheme 15: Glycolysis reaction of PCT by diethylene glycol.
Scheme 16: Polymerisation–depolymerisation cycle of 3,4-T6GBL.
Scheme 17: Polymerisation–depolymerisation cycle of 2,3-HDB.
Scheme 18: Hydrogenative depolymerisation of PBPAC by molecular Ru catalysts.
Scheme 19: Catalytic hydrolysis (top), alcoholysis (middle) and aminolysis (bottom) reactions of PBPAC.
Scheme 20: Hydrogenative depolymerisation of PPC (top) and PEC (bottom) by molecular Ru catalysts.
Scheme 21: Polymerisation-depolymerisation cycle of BEP.
Scheme 22: Hydrogenolysis of polyamides using soluble Ru catalysts.
Scheme 23: Catalytic depolymerisation of epoxy resin/carbon fibres composite.
Scheme 24: Depolymerisation of polyethers with metal salt catalysts and acyl chlorides.
Scheme 25: Proposed mechanism for the iron-catalysed depolymerisation reaction of polyethers. Adapted with per...
Beilstein J. Org. Chem. 2021, 17, 343–378, doi:10.3762/bjoc.17.32
Graphical Abstract
Figure 1: Stabilizing interaction in the CF3CH2+ carbenium ion (top) and structure of the first observable fl...
Scheme 1: Isodesmic equations accounting for the destabilizing effect of the CF3 group. ΔE in kcal⋅mol−1, cal...
Scheme 2: Stabilizing effect of fluorine atoms by resonance electron donation in carbenium ions (δ in ppm).
Scheme 3: Direct in situ NMR observation of α-(trifluoromethyl)carbenium ion or protonated alcohols. Δδ = δ19...
Scheme 4: Reported 13C NMR chemical shifts for the α-(trifluoromethyl)carbenium ion 10c (δ in ppm).
Scheme 5: Direct NMR observation of α-(trifluoromethyl)carbenium ions in situ (δ in ppm).
Scheme 6: Illustration of the ion pair solvolysis mechanism for sulfonate 13f. YOH = solvent.
Figure 2: Solvolysis rate for 13a–i and 17.
Figure 3: Structures of allyl triflates 18 and 19 and allyl brosylate 20. Bs = p-BrC6H4SO2.
Figure 4: Structure of tosylate derivatives 21.
Figure 5: a) Structure of triflate derivatives 22. b) Stereochemistry outcomes of the reaction starting from (...
Scheme 7: Solvolysis reaction of naphthalene and anthracenyl derivatives 26 and 29.
Figure 6: Structure of bisarylated derivatives 34.
Figure 7: Structure of bisarylated derivatives 36.
Scheme 8: Reactivity of 9c in the presence of a Brønsted acid.
Scheme 9: Cationic electrocyclization of 38a–c under strongly acidic conditions.
Scheme 10: Brønsted acid-catalyzed synthesis of indenes 42 and indanes 43.
Scheme 11: Reactivity of sulfurane 44 in triflic acid.
Scheme 12: Solvolysis of triflate 45f in alcoholic solvents.
Scheme 13: Synthesis of labeled 18O-52.
Scheme 14: Reactivity of sulfurane 53 in triflic acid.
Figure 8: Structure of tosylates 56 and 21f.
Scheme 15: Resonance forms in benzylic carbenium ions.
Figure 9: Structure of pyrrole derivatives 58 and 59.
Scheme 16: Resonance structure 60↔60’.
Scheme 17: Ga(OTf)3-catalyzed synthesis of 3,3’- and 3,6’-bis(indolyl)methane from trifluoromethylated 3-indol...
Scheme 18: Proposed reaction mechanism.
Scheme 19: Metal-free 1,2-phosphorylation of 3-indolylmethanols.
Scheme 20: Superacid-mediated arylation of thiophene derivatives.
Scheme 21: In situ mechanistic NMR investigations.
Scheme 22: Proposed mechanisms for the prenyltransferase-catalyzed condensation.
Scheme 23: Influence of a CF3 group on the allylic SN1- and SN2-mechanism-based reactions.
Scheme 24: Influence of the CF3 group on the condensation reaction.
Scheme 25: Solvolysis of 90 in TFE.
Scheme 26: Solvolysis of allyl triflates 94 and 97 and isomerization attempt of 96.
Scheme 27: Proposed mechanism for the formation of 95.
Scheme 28: Formation of α-(trifluoromethyl)allylcarbenium ion 100 in a superacid.
Scheme 29: Lewis acid activation of CF3-substituted allylic alcohols.
Scheme 30: Bimetallic-cluster-stabilized α-(trifluoromethyl)carbenium ions.
Scheme 31: Reactivity of cluster-stabilized α-(trifluoromethyl)carbenium ions.
Scheme 32: α-(Trifluoromethyl)propargylium ion 122↔122’ generated from silyl ether 120 in a superacid.
Scheme 33: Formation of α-(trifluoromethyl)propargylium ions from CF3-substituted propargyl alcohols.
Scheme 34: Direct NMR observation of the protonation of some trifluoromethyl ketones in situ and the correspon...
Scheme 35: Selected resonance forms in protonated fluoroketone derivatives.
Scheme 36: Acid-catalyzed Friedel–Crafts reactions of trifluoromethyl ketones 143a,b and 147a–c.
Scheme 37: Enantioselective hydroarylation of CF3-substituted ketones.
Scheme 38: Acid-catalyzed arylation of ketones 152a–c.
Scheme 39: Reactivity of 156 in a superacid.
Scheme 40: Reactivity of α-CF3-substituted heteroaromatic ketones and alcohols as well as 1,3-diketones.
Scheme 41: Reactivity of 168 with benzene in the presence of a Lewis or Brønsted acid.
Scheme 42: Acid-catalyzed three-component asymmetric reaction.
Scheme 43: Anodic oxidation of amines 178a–c and proposed mechanism.
Scheme 44: Reactivity of 179b in the presence of a strong Lewis acid.
Scheme 45: Trifluoromethylated derivatives as precursors of trifluoromethylated iminium ions.
Scheme 46: Mannich reaction with trifluoromethylated hemiaminal 189.
Scheme 47: Suitable nucleophiles reacting with 192 after Lewis acid activation.
Scheme 48: Strecker reaction involving the trifluoromethylated iminium ion 187.
Scheme 49: Reactivity of 199 toward nucleophiles.
Scheme 50: Reactivity of 204a with benzene in the presence of a Lewis acid.
Scheme 51: Reactivity of α-(trifluoromethyl)-α-chloro sulfides in the presence of strong Lewis acids.
Scheme 52: Anodic oxidation of sulfides 213a–h and Pummerer rearrangement.
Scheme 53: Mechanism for the electrochemical oxidation of the sulfide 213a.
Scheme 54: Reactivity of (trifluoromethyl)diazomethane (217a) in HSO3F.
Figure 10: a) Structure of diazoalkanes 217a–c and b) rate-limiting steps of their decomposition.
Scheme 55: Deamination reaction of racemic 221 and enantioenriched (S)-221.
Scheme 56: Deamination reaction of labeled 221-d2. Elimination products were formed in this reaction, the yiel...
Scheme 57: Deamination reaction of 225-d2. Elimination products were also formed in this reaction in undetermi...
Scheme 58: Formation of 229 from 228 via 1,2-H-shift.
Scheme 59: Deamination reaction of 230. Elimination products were formed in this reaction, the yield of which ...
Scheme 60: Deamination of several diazonium ions. Elimination products were formed in these reactions, the yie...
Scheme 61: Solvolysis reaction mechanism of alkyl tosylates.
Scheme 62: Solvolysis outcome for the tosylates 248 and 249 in HSO3FSbF5.
Figure 11: Solvolysis rate of 248, 249, 252, and 253 in 91% H2SO4.
Scheme 63: Illustration of the reaction pathways. TsCl, pyridine, −5 °C (A); 98% H2SO4, 30 °C (B); 98% H2SO4, ...
Scheme 64: Proposed solvolysis mechanism for the aliphatic tosylate 248.
Scheme 65: Solvolysis of the derivatives 259 and 260.
Scheme 66: Solvolysis of triflate 261. SOH = solvent.
Scheme 67: Intramolecular Friedel–Crafts alkylations upon the solvolysis of triflates 264 and 267.
Scheme 68: α-CF3-enhanced γ-silyl elimination of cyclobutyltosylates 270a,b.
Scheme 69: γ-Silyl elimination in the synthesis of a large variety of CF3-substituted cyclopropanes. Pf = pent...
Scheme 70: Synthetic pathways to 281. aNMR yields.
Scheme 71: The cyclopropyl-substituted homoallylcyclobutylcarbenium ion manifold.
Scheme 72: Reactivity of CF3-substituted cyclopropylcarbinyl derivatives 287a–c. LG = leaving group.
Scheme 73: Reactivity of CF3-substituted cyclopropylcarbinyl derivatives 291a–c.
Scheme 74: Superacid-promoted dimerization or TFP.
Scheme 75: Reactivity of TFP in a superacid.
Scheme 76: gem-Difluorination of α-fluoroalkyl styrenes via the formation of a “hidden” α-RF-substituted carbe...
Scheme 77: Solvolysis of CF3-substituted pentyne 307.
Scheme 78: Photochemical rearrangement of 313.
Figure 12: Structure of 2-norbornylcarbenium ion 318 and argued model for the stabilization of this cation.
Figure 13: Structures and solvolysis rate (TFE, 25 °C) of the sulfonates 319–321. Mos = p-MeOC6H4SO2.
Scheme 79: Mechanism for the solvolysis of 323. SOH = solvent.
Scheme 80: Products formed by the hydrolysis of 328.
Scheme 81: Proposed carbenium ion intermediates in an equilibrium during the solvolysis of tosylates 328, 333,...
Beilstein J. Org. Chem. 2020, 16, 2999–3007, doi:10.3762/bjoc.16.249
Graphical Abstract
Figure 1: Design of chiral calix[4]arene-based receptors for anions.
Scheme 1: Synthesis of the calix[4]arene-based chiral anionic receptors 7 and 8.
Figure 2: X-ray structure of 4a: (a) Top view into the cavity. (b) Side view of the same cavity.
Figure 3: X-ray structure of 7a: (a) Hydrogen bonding interactions (black) in a dimeric motif, chalcogen inte...
Figure 4: X-ray structure of 7d, showing hydrogen bonds between the ureido units (green) and hydrogen bonding...
Figure 5: 1H NMR titration of 7c with N-acetyl-ᴅ-phenylalaninate and N-acetyl-ʟ-phenylalaninate (as TBA salts...
Beilstein J. Org. Chem. 2020, 16, 2728–2738, doi:10.3762/bjoc.16.223
Graphical Abstract
Figure 1: Chemical structures of (a) PBImN (N = 4, 10, 12 and 14) and (b) ATP, ADP and AMP.
Scheme 1: Schematic representation of ATP sensing by multivalent assemblies of PBImN in aqueous media.
Scheme 2: Synthetic route for the preparation of PBImNs.
Figure 2: (a) Absorption and (b) emission spectra of PBImN (50 µM) derivatives in buffer. (c) Absorption and ...
Figure 3: FESEM images of PBIm12 (a) without and (b) with ATP. (c) Emission spectral changes of PBIm12 (75 µM...
Figure 4: a) Emission changes of PBIm12 (75 µM) upon the addition of ATP, ADP, AMP and PPi in buffer. Bar dia...
Beilstein J. Org. Chem. 2020, 16, 2272–2281, doi:10.3762/bjoc.16.188
Graphical Abstract
Figure 1: Structure of PBA-BODIPY (1) and schematic representation of dextran (Dex) and PBA-BODIPY conjugated...
Scheme 1: Schematic representation of dextran/PBA-BODIPY bioconjugations in: A. conventional solution-based c...
Figure 2: A) Amount of recovered PBA-BODIPY (1, i.e., nonreacted 1) in the mixtures DMSO/EtOH and in the seri...
Figure 3: A) UV–vis absorption and B) fluorescence emission spectra (λexc = 380 nm) of the BODIPY-dextran con...
Figure 4: A) Hydrodynamic diameter of (nm) conjugate Dex-1b (at 1 mg/mL in H2O, black curve) and PBS (red cur...
Figure 5: Fluorescence emission spectra of pyrene (4.4 × 10−8 M) in water and in a water solution in the pres...
Beilstein J. Org. Chem. 2020, 16, 1830–1836, doi:10.3762/bjoc.16.150
Graphical Abstract
Scheme 1: Synthetic scheme of the 3-arylated-4-nitrophenols 5.
Figure 1: X-ray crystallography of the major isomer of 4a. The thermal ellipsoids indicate 50% probability.
Scheme 2: Conversion from 3a to 4a and one-pot synthesis of 4a.
Scheme 3: Deuteration of cyclohexanone 4a.
Scheme 4: A plausible mechanism for the formation of 5a.
Figure 2: Resonance structure of nitroalkenes 1b and 1d.
Beilstein J. Org. Chem. 2020, 16, 1662–1682, doi:10.3762/bjoc.16.138
Graphical Abstract
Scheme 1: Schematic representation of the Pauson–Khand reaction.
Scheme 2: Substrates included in this review.
Scheme 3: Commonly accepted mechanism for the Pauson–Khand reaction.
Scheme 4: Regioselectivity of the PKR.
Scheme 5: Variability at the acetylenic and olefinic counterpart.
Scheme 6: Pauson–Khand reaction of fluoroolefinic enynes reported by the group of Ishizaki [46].
Scheme 7: PKR of enynes bearing fluorinated groups on the alkynyl moiety, reported by the group of Ishizaki [46]....
Scheme 8: Intramolecular PKR of 1,7-enynes reported by the group of Billard [47].
Scheme 9: Intramolecular PKR of 1,7-enynes reported by the group of Billard [48].
Scheme 10: Intramolecular PKR of 1,7-enynes by the group of Bonnet-Delpon [49]. Reaction conditions: i) Co(CO)8 (1...
Scheme 11: Intramolecular PKR of 1,6-enynes reported by the group of Ichikawa [50].
Scheme 12: Intramolecular Rh(I)-catalyzed PKR reported by the group of Hammond [52].
Scheme 13: Intramolecular PKR of allenynes reported by the group of Osipov [53].
Scheme 14: Intramolecular PKR of 1,7-enynes reported by the group of Osipov [53].
Scheme 15: Intramolecular PKR of fluorine-containing 1,6-enynes reported by the Konno group [54].
Scheme 16: Diastereoselective PKR with enantioenriched fluorinated enynes 34 [55].
Scheme 17: Intramolecular PKR reported by the group of Martinez-Solorio [56].
Scheme 18: Fluorine substitution at the olefinic counterpart.
Scheme 19: Synthesis of fluorinated enynes 37 [59].
Scheme 20: Fluorine-containing substrates in PKR [59].
Scheme 21: Pauson Khand reaction for fluorinated enynes by the Fustero group: scope and limitations [59].
Scheme 22: Synthesis of chloro and bromo analogues [59].
Scheme 23: Dimerization pathway [59].
Scheme 24: Synthesis of fluorine-containing N-tethered 1,7-enynes [61].
Scheme 25: Intramolecular PKR of chiral N-tethered fluorinated 1,7-enynes [61].
Scheme 26: Examples of further modifications to the Pauson−Khand adducts [61].
Scheme 27: Asymmetric synthesis the fluorinated enynes 53.
Scheme 28: Intramolecular PKR of chiral N-tethered 1,7-enynes 53 [64].
Scheme 29: Intramolecular PKR of chiral N-tethered 1,7-enyne bearing a vinyl fluoride [64].
Scheme 30: Catalytic intramolecular PKR of chiral N-tethered 1,7-enynes [64].
Scheme 31: Model fluorinated alkynes used by Riera and Fustero [70].
Scheme 32: PKR with norbornadiene and fluorinated alkynes 58 [71].
Scheme 33: Nucleophilic addition/detrifluoromethylation and retro Diels-Alder reactions [70].
Scheme 34: Tentative mechanism for the nucleophilic addition/retro-aldol reaction sequence.
Scheme 35: Catalytic PKR with norbornadiene [70].
Scheme 36: Scope of the PKR of trifluoromethylalkynes with norbornadiene [72].
Scheme 37: DBU-mediated detrifluoromethylation [72].
Scheme 38: A simple route to enone 67, a common intermediate in the total synthesis of α-cuparenone.
Scheme 39: Effect of the olefin partner in the regioselectivity of the PKR with trifluoromethyl alkynes [79].
Scheme 40: Intermolecular PKR of trifluoromethylalkynes with 2-norbornene reported by the group of Konno [54].
Scheme 41: Intermolecular PKR of diarylalkynes with 2-norbornene reported by the group of Helaja [80].
Scheme 42: Intermolecular PKR reported by León and Fernández [81].
Scheme 43: PKR reported with cyclopropene 73 [82].
Beilstein J. Org. Chem. 2020, 16, 1554–1563, doi:10.3762/bjoc.16.127
Graphical Abstract
Figure 1: FTIR analysis of βNS-CDI 1:4, before and after treatment for 4 h in H2O at 40 °C, synthesized with ...
Figure 2: Thermogravimetric analysis of β-CD-based carbonate nanosponges, obtained through solution (DMF) and...
Figure 3: Thermogravimetric analysis of α, β and γ-CD-based carbonate nanosponges, obtained through ball-mill...
Figure 4: Adsorption of organic dyes by ball-mill synthesized β-CD-based carbonate nanosponges. Conditions: a...
Figure 5: ζ-Potential of bm cyclodextrin nanosponges with relative STDev (mV).
Figure 6: Hydrolysis of the imidazoyl carbonyl group in water at 40 °C.
Figure 7: Nitrogen content in weight % in cyclodextrins NS-CDI from ball mill synthesis. a) comparison betwee...
Figure 8: Simplified schematic reaction and procedure for obtaining the dye-functionalized βNS-CDI. Surface z...
Beilstein J. Org. Chem. 2020, 16, 1154–1162, doi:10.3762/bjoc.16.102
Graphical Abstract
Figure 1: (A) Transition-metal-containing and (B) pure organic phosphorescent materials reported thus far (bp...
Figure 2: (A) Chemical structures of fluorescent bistolane derivatives previously developed by our group and ...
Scheme 1: Synthetic pathway for fluorinated benzil (2) and bisbenzil (3) derivatives.
Scheme 2: Proposed mechanism of Pd(II)-catalyzed alkyne oxidation by dimethyl sulfoxide (DMSO).
Figure 3: Mulliken charge distributions of fluorinated 1a and nonfluorinated 1c obtained from density functio...
Figure 4: Absorption and photoluminescence (PL) spectra of (A) 2a, (B) 2b, (C) 3a, (D) 3b, and (E) 3c in tolu...
Figure 5: Distributions of molecular orbitals (isosurface value: 0.04 a.u.) involved in vertical electronic t...
Beilstein J. Org. Chem. 2020, 16, 1066–1074, doi:10.3762/bjoc.16.93
Graphical Abstract
Scheme 1: Synthesis of compounds 7a and 7b from carbazole 1. i) NBS, DMF, 0 °C to rt, 24 h. ii) n-hexyl bromi...
Figure 1: TGA (a) and DSC (b) curve of the compounds 7a and 7b.
Figure 2: Cyclic voltammograms of compounds 7a and 7b in dichloromethane under argon atmosphere at room tempe...
Figure 3: Energy levels of compounds 7a and 7b.
Figure 4: Normalised UV–vis and PL spectra of compounds 7a and 7b in dichloromethane.
Figure 5: Normalised UV–vis spectra of compounds 7a and 7b in different solvents.
Figure 6: PL spectra of compounds 7a and 7b in different solvents (A–H).
Beilstein J. Org. Chem. 2020, 16, 982–988, doi:10.3762/bjoc.16.87
Graphical Abstract
Scheme 1: One-day workflow for fragment-based library generation. QC: Quality control. MPLC: Medium-pressure ...
Figure 1: Top: high-power blue LED photoreactors. Bottom, from left to right: photoreactor OFF, ON, and ON th...
Figure 2: TLC–MS equipment: analysis of 5 reactions in 5 minutes.
Figure 3: Pre-QC validation by 60 MHz benchtop NMR.
Scheme 2: Scope of the fragment-based library generation: BCP-amines and azetidines. See Supporting Information File 1 for experimental de...
Scheme 3: Scope of the fragment-based library generation: pyrrolidines, piperidines and morpholines. See Supporting Information File 1 for...
Beilstein J. Org. Chem. 2020, 16, 917–955, doi:10.3762/bjoc.16.83
Graphical Abstract
Figure 1: Chemical structures of the porphyrinoids and their absorption spectra: in bold are highlighted the ...
Figure 2: Photophysical and photochemical processes (Por = porphyrin). Adapted from [12,18].
Figure 3: Main dual photocatalysts and their oxidative/reductive excited state potentials, including porphyri...
Scheme 1: Photoredox alkylation of aldehydes with diazo acetates using porphyrins and a Ru complex. aUsing a ...
Scheme 2: Proposed mechanism for the alkylation of aldehydes with diazo acetates in the presence of TPP.
Scheme 3: Arylation of heteroarenes with aryldiazonium salts using TPFPP as photocatalyst, and corresponding ...
Scheme 4: A) Scope with different aryldiazonium salts and enol acetates. B) Photocatalytic cycles and compari...
Scheme 5: Photoarylation of isopropenyl acetate A) Comparison between batch and continuous-flow approaches an...
Scheme 6: Dehalogenation induced by red light using thiaporphyrin (STPP).
Scheme 7: Applications of NiTPP as both photoreductant and photooxidant.
Scheme 8: Proposed mechanism for obtaining tetrahydroquinolines by reductive quenching.
Scheme 9: Selenylation and thiolation of anilines.
Scheme 10: NiTPP as photoredox catalyst in oxidative and reductive quenching, in comparison with other photoca...
Scheme 11: C–O bond cleavage of 1-phenylethanol using a cobalt porphyrin (CoTMPP) under visible light.
Scheme 12: Hydration of terminal alkynes by RhIII(TSPP) under visible light irradiation.
Scheme 13: Regioselective photocatalytic hydro-defluorination of perfluoroarenes by RhIII(TSPP).
Scheme 14: Formation of 2-methyl-2,3-dihydrobenzofuran by intramolecular hydro-functionalization of allylpheno...
Scheme 15: Photocatalytic oxidative hydroxylation of arylboronic acids using UNLPF-12 as heterogeneous photoca...
Scheme 16: Photocatalytic oxidative hydroxylation of arylboronic acids using MOF-525 as heterogeneous photocat...
Scheme 17: Preparation of the heterogeneous photocatalyst CNH.
Scheme 18: Photoinduced sulfonation of alkenes with sulfinic acid using CNH as photocatalyst.
Scheme 19: Sulfonic acid scope of the sulfonation reactions.
Scheme 20: Regioselective sulfonation reaction of arimistane.
Scheme 21: Synthesis of quinazolin-4-(3H)-ones.
Scheme 22: Selective photooxidation of aromatic benzyl alcohols to benzaldehydes using Pt/PCN-224(Zn).
Scheme 23: Photooxidation of benzaldehydes to benzoic acids using Pt or Pd porphyrins.
Scheme 24: Photocatalytic reduction of various nitroaromatics using a Ni-MOF.
Scheme 25: Photoinduced cycloadditions of CO2 with epoxides by MOF1.
Figure 4: Electronic configurations of the species of oxygen. Adapted from [66].
Scheme 26: TPP-photocatalyzed generation of 1O2 and its application in organic synthesis. Adapted from [67-69].
Scheme 27: Pericyclic reactions involving singlet oxygen and their mechanisms. Adapted from [67].
Scheme 28: First scaled up ascaridole preparation from α-terpinene.
Scheme 29: Antimalarial drug synthesis using an endoperoxidation approach.
Scheme 30: Photooxygenation of colchicine.
Scheme 31: Synthesis of (−)-pinocarvone from abundant (+)-α-pinene.
Scheme 32: Seeberger’s semi-synthesis of artemisinin.
Scheme 33: Synthesis of artemisinin using TPP and supercritical CO2.
Scheme 34: Synthesis of artemisinin using chlorophyll a.
Scheme 35: Quercitol stereoisomer preparation.
Scheme 36: Photocatalyzed preparation of naphthoquinones.
Scheme 37: Continuous endoperoxidation of conjugated dienes and subsequent rearrangements leading to oxidized ...
Scheme 38: The Opatz group total synthesis of (–)-oxycodone.
Scheme 39: Biomimetic syntheses of rhodonoids A, B, E, and F.
Scheme 40: α-Photooxygenation of chiral aldehydes.
Scheme 41: Asymmetric photooxidation of indanone β-keto esters by singlet oxygen using PTC as a chiral inducer...
Scheme 42: Asymmetric photooxidation of both β-keto esters and β-keto amides by singlet oxygen using PTC-2 as ...
Scheme 43: Bifunctional photo-organocatalyst used for the asymmetric oxidation of β-keto esters and β-keto ami...
Scheme 44: Mechanism of singlet oxygen oxidation of sulfides to sulfoxides.
Scheme 45: Controlled oxidation of sulfides to sulfoxides using protonated porphyrins as photocatalysts. aIsol...
Scheme 46: Photochemical oxidation of sulfides to sulfoxides using PdTPFPP as photocatalyst.
Scheme 47: Controlled oxidation of sulfides to sulfoxides using SnPor@PAF as a photosensitizer.
Scheme 48: Syntheses of 2D-PdPor-COF and 3D-Pd-COF.
Scheme 49: Photocatalytic oxidation of A) thioanisole to methyl phenyl sulfoxide and B) various aryl sulfides,...
Scheme 50: General mechanism for oxidation of amines to imines.
Scheme 51: Oxidation of secondary amines to imines.
Scheme 52: Oxidation of secondary amines using Pd-TPFPP as photocatalyst.
Scheme 53: Oxidative amine coupling using UNLPF-12 as heterogeneous photocatalyst.
Scheme 54: Synthesis of Por-COF-1 and Por-COF-2.
Scheme 55: Photocatalytic oxidation of amines to imines by Por-COF-2.
Scheme 56: Photocyanation of primary amines.
Scheme 57: Synthesis of ᴅ,ʟ-tert-leucine hydrochloride.
Scheme 58: Photocyanation of catharanthine and 16-O-acetylvindoline using TPP.
Scheme 59: Photochemical α-functionalization of N-aryltetrahydroisoquinolines using Pd-TPFPP as photocatalyst.
Scheme 60: Ugi-type reaction with 1,2,3,4-tetrahydroisoquinoline using molecular oxygen and TPP.
Scheme 61: Ugi-type reaction with dibenzylamines using molecular oxygen and TPP.
Scheme 62: Mannich-type reaction of tertiary amines using PdTPFPP as photocatalyst.
Scheme 63: Oxidative Mannich reaction using UNLPF-12 as heterogeneous photocatalyst.
Scheme 64: Transformation of amines to α-cyanoepoxides and the proposed mechanism.
Beilstein J. Org. Chem. 2020, 16, 691–737, doi:10.3762/bjoc.16.67
Graphical Abstract
Scheme 1: Pharmaceuticals possessing a silicon or boron atom.
Scheme 2: The first Cu-catalyzed C(sp3)–Si bond formation.
Scheme 3: Conversion of benzylic phosphate 6 to the corresponding silane.
Scheme 4: Conversion of alkyl triflates to alkylsilanes.
Scheme 5: Conversion of secondary alkyl triflates to alkylsilanes.
Scheme 6: Conversion of alkyl iodides to alkylsilanes.
Scheme 7: Trapping of intermediate radical through cascade reaction.
Scheme 8: Radical pathway for conversion of alkyl iodides to alkylsilanes.
Scheme 9: Conversion of alkyl ester of N-hydroxyphthalimide to alkylsilanes.
Scheme 10: Conversion of gem-dibromides to bis-silylalkanes.
Scheme 11: Conversion of imines to α-silylated amines (A) and the reaction pathway (B).
Scheme 12: Conversion of N-tosylimines to α-silylated amines.
Scheme 13: Screening of diamine ligands.
Scheme 14: Conversion of N-tert-butylsulfonylimines to α-silylated amines.
Scheme 15: Conversion of aldimines to nonracemic α-silylated amines.
Scheme 16: Conversion of N-tosylimines to α-silylated amines.
Scheme 17: Reaction pathway [A] and conversion of aldehydes to α-silylated alcohols [B].
Scheme 18: Conversion of aldehydes to benzhydryl silyl ethers.
Scheme 19: Conversion of ketones to 1,2-diols (A) and conversion of imines to 1,2-amino alcohols (B).
Scheme 20: Ligand screening (A) and conversion of aldehydes to α-silylated alcohols (B).
Scheme 21: Conversion of aldehydes to α-silylated alcohols.
Scheme 22: 1,4-Additions to α,β-unsaturated ketones.
Scheme 23: 1,4-Additions to unsaturated ketones to give β-silylated derivatives.
Scheme 24: Additions onto α,β-unsaturated lactones to give β-silylated lactones.
Scheme 25: Conversion of α,β-unsaturated to β-silylated lactams.
Scheme 26: Conversion of N-arylacrylamides to silylated oxindoles.
Scheme 27: Conversion of α,β-unsaturated carbonyl compounds to silylated tert-butylperoxides.
Scheme 28: Catalytic cycle for Cu(I) catalyzed α,β-unsaturated compounds.
Scheme 29: Conversion of p-quinone methides to benzylic silanes.
Scheme 30: Conversion of α,β-unsaturated ketimines to regio- and stereocontrolled allylic silanes.
Scheme 31: Conversion of α,β-unsaturated ketimines to enantioenriched allylic silanes.
Scheme 32: Regioselective conversion of dienedioates to allylic silanes.
Scheme 33: Conversion of alkenyl-substituted azaarenes to β-silylated adducts.
Scheme 34: Conversion of conjugated benzoxazoles to enantioenriched β-silylated adducts.
Scheme 35: Conversion of α,β-unsaturated carbonyl indoles to α-silylated N-alkylated indoles.
Scheme 36: Conversion of β-amidoacrylates to α-aminosilanes.
Scheme 37: Conversion of α,β-unsaturated ketones to enantioenriched β-silylated ketones, nitriles, and nitro d...
Scheme 38: Regio-divergent silacarboxylation of allenes.
Scheme 39: Silylation of diazocarbonyl compounds, (A) asymmetric and (B) racemic.
Scheme 40: Enantioselective hydrosilylation of alkenes.
Scheme 41: Conversion of 3-acylindoles to indolino-silanes.
Scheme 42: Proposed mechanism for the silylation of 3-acylindoles.
Scheme 43: Silyation of N-chlorosulfonamides.
Scheme 44: Conversion of acyl silanes to α-silyl alcohols.
Scheme 45: Conversion of N-tosylaziridines to β-silylated N-tosylamines.
Scheme 46: Conversion of N-tosylaziridines to silylated N-tosylamines.
Scheme 47: Conversion of 3,3-disubstituted cyclopropenes to silylated cyclopropanes.
Scheme 48: Conversion of conjugated enynes to 1,3-bis(silyl)propenes.
Scheme 49: Proposed sequence for the Cu-catalyzed borylation of substituted alkenes.
Scheme 50: Cu-catalyzed synthesis of nonracemic allylic boronates.
Scheme 51: Cu–NHC catalyzed synthesis of α-substituted allylboronates.
Scheme 52: Synthesis of α-chiral (γ-alkoxyallyl)boronates.
Scheme 53: Cu-mediated formation of nonracemic cis- or trans- 2-substituted cyclopropylboronates.
Scheme 54: Cu-catalyzed synthesis of γ,γ-gem-difluoroallylboronates.
Scheme 55: Cu-catalyzed hydrofunctionalization of internal alkenes and vinylarenes.
Scheme 56: Cu-catalyzed Markovnikov and anti-Markovnikov borylation of alkenes.
Scheme 57: Cu-catalyzed borylation/ortho-cyanation/Cope rearrangement.
Scheme 58: Borylfluoromethylation of alkenes.
Scheme 59: Cu-catalyzed synthesis of tertiary nonracemic alcohols.
Scheme 60: Synthesis of densely functionalized and synthetically versatile 1,2- or 4,3-borocyanated 1,3-butadi...
Scheme 61: Cu-catalyzed trifunctionalization of allenes.
Scheme 62: Cu-catalyzed selective arylborylation of arenes.
Scheme 63: Asymmetric borylative coupling between styrenes and imines.
Scheme 64: Regio-divergent aminoboration of unactivated terminal alkenes.
Scheme 65: Cu-catalyzed 1,4-borylation of α,β-unsaturated ketones.
Scheme 66: Cu-catalyzed protodeboronation of α,β-unsaturated ketones.
Scheme 67: Cu-catalyzed β-borylation of α,β-unsaturated imines.
Scheme 68: Cu-catalyzed synthesis of β-trifluoroborato carbonyl compounds.
Scheme 69: Asymmetric 1,4-borylation of α,β-unsaturated carbonyl compounds.
Scheme 70: Cu-catalyzed ACB and ACA reactions of α,β-unsaturated 2-acyl-N-methylimidazoles.
Scheme 71: Cu-catalyzed diborylation of aldehydes.
Scheme 72: Umpolung pathway for chiral, nonracemic tertiary alcohol synthesis (top) and proposed mechanism for...
Scheme 73: Cu-catalyzed synthesis of α-hydroxyboronates.
Scheme 74: Cu-catalyzed borylation of ketones.
Scheme 75: Cu-catalyzed borylation of unactivated alkyl halides.
Scheme 76: Cu-catalyzed borylation of allylic difluorides.
Scheme 77: Cu-catalyzed borylation of cyclic and acyclic alkyl halides.
Scheme 78: Cu-catalyzed borylation of unactivated alkyl chlorides and bromides.
Scheme 79: Cu-catalyzed decarboxylative borylation of carboxylic acids.
Scheme 80: Cu-catalyzed borylation of benzylic, allylic, and propargylic alcohols.
Beilstein J. Org. Chem. 2020, 16, 362–383, doi:10.3762/bjoc.16.35
Graphical Abstract
Scheme 1: Synthesis of pyridylphosphine ligands.
Figure 1: Pyridylphosphine ligands.
Scheme 2: Synthesis of piperidyl- and oxazinylphosphine ligands.
Scheme 3: Synthesis of linear multi-chelate pyridylphosphine ligands.
Scheme 4: Synthesis of chiral acetal pyridylphosphine ligands.
Scheme 5: Synthesis of diphenylphosphine-substituted triazine ligands.
Scheme 6: Synthesis of (pyridine-2-ylmethyl)phosphine ligands.
Scheme 7: Synthesis of diphosphine pyrrole ligands.
Scheme 8: Synthesis of 4,5-diazafluorenylphosphine ligands.
Scheme 9: Synthesis of thioether-containing pyridyldiphosphine ligands starting from ethylene sulfide and dip...
Scheme 10: Synthesis of monoterpene-derived phosphine pyridine ligands.
Scheme 11: Synthesis of N-phenylphosphine-substituted imidazole ligands.
Scheme 12: Synthesis of triazol-4-ylphosphine ligands.
Scheme 13: Synthesis of phosphanyltriazolopyridines and product selectivity depending on the substituents’ eff...
Scheme 14: Synthesis of PTA-phosphine ligands.
Scheme 15: Synthesis of isomeric phosphine dipyrazole ligands by varying the reaction temperature.
Scheme 16: Synthesis of N-tethered phosphine imidazolium ligands (route A) and diphosphine imidazolium ligands...
Scheme 17: Synthesis of {1-[2-(pyridin-2-yl)- (R = CH) and {1-[2-(pyrazin-2-yl)quinazolin-4-yl]naphthalen-2-yl...
Scheme 18: Synthesis of oxazolylindolylphosphine ligands 102.
Scheme 19: Synthesis of pyrrolylphosphine ligands.
Scheme 20: Synthesis of phosphine guanidinium ligands.
Scheme 21: Synthesis of a polydentate aminophosphine ligand.
Scheme 22: Synthesis of quinolylphosphine ligands.
Scheme 23: Synthesis of N-(triazolylmethyl)phosphanamine ligands.
Figure 2: Triazolylphosphanamine ligands synthesized by Wassenaar’s method [22].
Scheme 24: Synthesis of oxazaphosphorines.
Scheme 25: Synthesis of paracyclophane pyridylphosphine ligands.
Scheme 26: Synthesis of triazolylphosphine ligands.
Figure 3: Click-phosphine ligands.
Scheme 27: Ferrocenyl pyridylphosphine imine ligands.
Scheme 28: Synthesis of phosphinooxazolines (PHOX).
Scheme 29: Synthesis of ferrocenylphosphine oxazoles.
Beilstein J. Org. Chem. 2020, 16, 39–49, doi:10.3762/bjoc.16.6
Graphical Abstract
Figure 1: DAE photoswitch and photoswitchable peptides explored in this study. (A) The reversible photoisomer...
Figure 2: Two versions of the D. rerio embryotoxicity assay for DAE-modified peptides: timelines, peptide pho...
Figure 3: The in vivo toxicity against D. rerio embryos appears to be correlated with the empirical hydrophob...
Figure 4: D. rerio embryotoxicity of GS 1 and the photoswitchable analogues 2–20 correlated with their in vit...
Figure 5: Phototherapeutic cytotoxic action against HeLa cells of GS 1 and its photoswitchable analogues 2–20...
Beilstein J. Org. Chem. 2019, 15, 2774–2781, doi:10.3762/bjoc.15.269
Graphical Abstract
Scheme 1: Conventional method of synthesis of thiazolidine-2,4-dione derivatives.
Scheme 2: [2 + 2 + 2] Cyclotrimerization of N-methylthiazolidinedione.
Scheme 3: Unexpected product 5b obtained in the attempted NH-protection of thiazolidinedione with (Boc)2O.
Figure 1: Comparison of 13C NMR values of 9 and 5b.
Scheme 4: [2 + 2 + 2] Cyclotrimerization of dipropargylthiazolidinediones with propargyl halides.
Scheme 5: Formation of sultine 13 from compound 8b followed by DA reaction.
Scheme 6: Dipropargylation of 2,4-thiazolidinedione derivatives.
Scheme 7: [2 + 2 + 2] Cycloaddition in the presence of Wilkinson’s catalyst.
Scheme 8: N-Ester derivative 18 hydrolysis to N-acid derivative 22.
Scheme 9: Synthesis of triazolo derivative 24 via click reaction.
Beilstein J. Org. Chem. 2019, 15, 2710–2746, doi:10.3762/bjoc.15.264
Graphical Abstract
Figure 1: General classification of asymmetric electroorganic reactions.
Scheme 1: Asymmetric reduction of 4-acetylpyridine using a modified graphite cathode.
Scheme 2: Asymmetric hydrogenation of ketones using Raney nickel powder electrodes modified with optically ac...
Scheme 3: Asymmetric reduction of prochiral activated olefins with a poly-ʟ-valine-coated graphite cathode.
Scheme 4: Asymmetric reduction of prochiral carbonyl compounds, oximes and gem-dibromides on a poly-ʟ-valine-...
Scheme 5: Asymmetric hydrogenation of prochiral ketones with poly[RuIII(L)2Cl2]+-modified carbon felt cathode...
Scheme 6: Asymmetric hydrogenation of α-keto esters using chiral polypyrrole film-coated cathode incorporated...
Scheme 7: Quinidine and cinchonidine alkaloid-induced asymmetric electroreduction of acetophenone.
Scheme 8: Asymmetric electroreduction of 4- and 2-acetylpyridines at a mercury cathode in the presence of a c...
Scheme 9: Enantioselective reduction of 4-methylcoumarin in the presence of catalytic yohimbine.
Scheme 10: Cinchonine-induced asymmetric electrocarboxylation of 4-methylpropiophenone.
Scheme 11: Enantioselective hydrogenation of methyl benzoylformate using an alkaloid entrapped silver cathode.
Scheme 12: Alkaloid-induced enantioselective hydrogenation using a Cu nanoparticle cathode.
Scheme 13: Alkaloid-induced enantioselective hydrogenation of aromatic ketones using a bimetallic Pt@Cu cathod...
Scheme 14: Enantioselective reduction of ketones at mercury cathode using N,N'-dimethylquininium tetrafluorobo...
Scheme 15: Asymmetric synthesis of an amino acid using an electrode modified with amino acid oxidase and elect...
Scheme 16: Asymmetric oxidation of p-tolyl methyl sulfide using chemically modified graphite anode.
Scheme 17: Asymmetric oxidation of unsymmetric sulfides using poly(amino acid)-coated electrodes.
Scheme 18: Enantioselective, electocatalytic oxidative coupling on TEMPO-modified graphite felt electrode in t...
Scheme 19: Asymmetric electrocatalytic oxidation of racemic alcohols on a TEMPO-modified graphite felt electro...
Scheme 20: Asymmetric electrocatalytic lactonization of diols on TEMPO-modified graphite felt electrodes.
Scheme 21: Asymmetric electrochemical pinacolization in a chiral solvent.
Scheme 22: Asymmetric electroreduction using a chiral supporting electrolyte.
Scheme 23: Asymmetric anodic oxidation of enol acetates using chiral supporting electrolytes.
Scheme 24: Kinetic resolution of primary amines using a chiral N-oxyl radical mediator.
Scheme 25: Chiral N-oxyl-radical-mediated kinetic resolution of secondary alcohols via electrochemical oxidati...
Scheme 26: Chiral iodoarene-mediated asymmetric electrochemical lactonization.
Scheme 27: Os-catalyzed electrochemical asymmetric dihydroxylation of olefins using the Sharpless ligand and i...
Scheme 28: Asymmetric electrochemical epoxidation of olefins catalyzed by a chiral Mn-salen complex.
Scheme 29: Asymmetric electrooxidation of 1,2-diols, and amino alcohols using a chiral copper catalyst.
Scheme 30: Mechanism of asymmetric electrooxidation of 1,2-diols, and amino alcohols using a chiral copper cat...
Scheme 31: Enantioselective electrocarboxylation catalyzed by an electrogenerated chiral [CoI(salen)]− complex....
Scheme 32: Asymmetric oxidative cross coupling of 2-acylimidazoles with silyl enol ethers.
Scheme 33: Ni-catalyzed asymmetric electroreductive cleavage of allylic β-keto ester 89.
Scheme 34: Asymmetric alkylation using a combination of electrosynthesis and a chiral Ni catalyst.
Scheme 35: Mechanism of asymmetric alkylation using a combination of electrosynthesis and a chiral Ni catalyst....
Scheme 36: Asymmetric epoxidation by electrogenerated percarbonate and persulfate ions in the presence of chir...
Scheme 37: α-Oxyamination of aldehydes via anodic oxidation catalyzed by chiral secondary amines.
Scheme 38: The α-alkylation of aldehydes via anodic oxidation catalyzed by chiral secondary amines.
Scheme 39: Mechanism of α-alkylation of aldehydes via anodic oxidation catalyzed by chiral secondary amines.
Scheme 40: Electrochemical chiral secondary amine-catalyzed intermolecular α-arylation of aldehydes.
Scheme 41: Mechanism of electrochemical chiral secondary amine-catalyzed intermolecular α-arylation of aldehyd...
Scheme 42: Asymmetric cross-dehydrogenative coupling of tertiary amines with simple ketones via an electrochem...
Scheme 43: Electroenzymatic asymmetric reduction using enoate reductase.
Scheme 44: Assymetric reduction using alcohol dehydrogenase as the electrocatalyst.
Scheme 45: Asymmetric electroreduction catalyzed by thermophilic NAD-dependent alcohol dehydrogenase.
Scheme 46: Asymmetric epoxidation of styrene by electrochemical regeneration of flavin-dependent monooxygenase....
Scheme 47: Asymmetric electroreduction using a chloroperoxidase catalyst.
Scheme 48: Asymmetric electrochemical transformation mediated by hydrophobic vitamin B12.
Scheme 49: Diastereoselective cathodic reduction of phenylglyoxalic acids substituted with amines as chiral au...
Scheme 50: Ni-catalyzed asymmetric electroreductive cross coupling of aryl halides with α-chloropropanoic acid...
Scheme 51: Electrochemical Mannich addition of silyloxyfuran to in situ-generated N-acyliminium ions.
Scheme 52: Stereoselective electroreductive homodimerization of cinnamates attached to a camphor-derived chira...
Scheme 53: Diastereoselective electrochemical carboxylation of chiral α-bromocarboxylic acid derivatives.
Scheme 54: Electrocatalytic stereoselective conjugate addition of chiral β-dicarbonyl compounds to methyl viny...
Scheme 55: Stereoselective electrochemical carboxylation of chiral cinnamic acid derivatives under a CO2 atmos...
Scheme 56: Electrochemical diastereoselective α-alkylation of pyrrolidines attached with phosphorus-derived ch...
Scheme 57: Electrogenerated cyanomethyl anion-induced synthesis of chiral cis-β-lactams from amides bearing ch...
Scheme 58: Diastereoselective anodic oxidation followed by intramolecular cyclization of ω-hydroxyl amides bea...
Scheme 59: Electrochemical deprotonation of Ni(II) glycinate containing (S)-BPB as a chiral auxiliary: diaster...
Scheme 60: Enantioselective electroreductive coupling of diaryl ketones with α,β-unsaturated carbonyl compound...
Scheme 61: Asymmetric total synthesis of ropivacaine and its analogues using a electroorganic reaction as a ke...
Scheme 62: Asymmetric total synthesis of (−)-crispine A and its natural enantiomer via anodic cyanation of tet...
Scheme 63: Asymmetric oxidative electrodimerization of cinnamic acid derivatives as key step for the synthesis...
Beilstein J. Org. Chem. 2019, 15, 2612–2622, doi:10.3762/bjoc.15.254
Graphical Abstract
Figure 1: Structures of the dyes 16–19.
Scheme 1: Synthesis of the precursors 2, 3, and 5.
Scheme 2: Synthesis of the precursor triflates 8–11.
Scheme 3: Synthesis of 12–15 and the organoboron dyes 16–19.
Figure 2: UV–vis absorption (solid line) and fluorescence (dashed line) spectra of a) 16, b) 17, c) 18, and d...
Scheme 4: Jablonski diagram representing the photophysical processes in the dyes 16–19.
Figure 3: Transient absorption spectrum (600 ns delay) of dye 17 in nitrogen-purged acetonitrile on excitatio...
Figure 4: Fluorescence titrations of the dyes (ca. 4–11 μM) with Bu4NF in acetonitrile. a) 16 (up to 156 equi...
Beilstein J. Org. Chem. 2019, 15, 2552–2562, doi:10.3762/bjoc.15.248
Graphical Abstract
Figure 1: Molecular structure of Nile red (NR).
Figure 2: Fluorescence (a) and absorption (b) spectra of NR in solvents of different polarity at 25 °C. The s...
Figure 3: Solvatochromic plot of the absorption (νa) and fluorescence (νf) maxima of NR in a series of solven...
Figure 4: Absorption (a) and fluorescence (a, b) spectra of NR in PMMA (350 kg/mol) film 500 nm thin at diffe...
Figure 5: Dependence of the fluorescence maximum (νf) of NR on the excitation wavelength (λe) in rigid PMMA m...
Figure 6: Absorption (a) and fluorescence (a, b) spectra of NR in ethyl acetate (EtOAc) at different excitati...
Beilstein J. Org. Chem. 2019, 15, 2390–2397, doi:10.3762/bjoc.15.231
Graphical Abstract
Scheme 1: Three synthetic approaches to dihydrotetrazolo[1,5-a]pyrimidines.
Scheme 2: Three-component reaction of 1, 7a,b and 8a–d in water.
Figure 1: Molecular structure of 9a according to X-ray data. Displacement ellipsoids are shown at the 50% pro...
Scheme 3: Three-component reaction of 5-aminotetrazole (1) with formaldehyde (7a) and acetylacetone (10).
Scheme 4: a) Three-component reaction of 5-aminotetrazole (1) with acetaldehyde (7b) and ethyl 4,4,4-trifluor...
Beilstein J. Org. Chem. 2019, 15, 1996–2002, doi:10.3762/bjoc.15.195
Graphical Abstract
Figure 1: Inherent chirality generated by meta-substitution – the two structures are non-superposable mirror ...
Figure 2: General approach by Albrecht for MIC directed cyclometalation via C–H activation; M = Ru(II), Ir(II...
Figure 3: Concept of cyclometalated calix[4]arene target.
Scheme 1: Synthesis of model mesoionic carbene 5.
Scheme 2: Attempted Ullmann-coupling to give monoazide 7.
Scheme 3: Synthesis of monoazidocalix[4]arene 7 under optimized conditions.
Scheme 4: Synthesis of the putative calix[4]arene mesoionic carbene ruthenium complex 13.
Figure 4: High-resolution mass spectrum (ESI+) of putative ruthenacycle calix[4]arene 13.
Beilstein J. Org. Chem. 2019, 15, 1913–1924, doi:10.3762/bjoc.15.187
Graphical Abstract
Figure 1: Structures of the compounds used in this study and labelling scheme for NMR spectra.
Figure 2: Spectra of complexes [1(LysOMe)2], [1(ArgOMe)2], [1(HisOMe)2]: 1H NMR (a–g) and ROESY (h–j) in meth...
Figure 3: CD (a) and UV (b) spectra of complexes [1(LysOMe)2], [1(PheOMe)2], [1(ValOMe)2], [1(ArgOMe)2], and [...
Figure 4: DOSY spectra of 1 (a), [1(LysOMe)2] (b), [1(ArgOMe)2] (c), [1(HisOMe)2] (d) and [LysOMe + 1(LysOMe)2...
Figure 5: 1H NMR spectra of 1 (a), LysOMe (b), 1H NMR and DOSY spectra of [1(LysOMe)2] (insets show the shape...
Figure 6: 1H NMR spectra of (R)-2 (a); [1((R)-2] (b); [1 + 1((R)-2] (c) (insets show the shape of signals f, ...
Figure 7: 1H NMR and DOSY spectra of (R)-2 (a); [1(R)-2] (b) (inset show the shape signals f, DMSO-d6, 298K, ...
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.
Beilstein J. Org. Chem. 2019, 15, 1581–1591, doi:10.3762/bjoc.15.162
Graphical Abstract
Figure 1: Glycosylated building blocks prepared for solid phase peptide synthesis (SPPS).
Scheme 1: A) Modification of Fmoc-Sieber-PS resin: a. piperidine in DMF (20% v/v), rt; 3 × 10 min; b. o-NBS-C...
Figure 2: Model AFGP analogues.
Figure 3: Conformational preferences of investigated glycopeptides.
Figure 4: Conformational preferences of monosaccharide moiety. A) cluster 1 for glycopeptide 3, B) cluster 1 ...
Beilstein J. Org. Chem. 2019, 15, 1523–1533, doi:10.3762/bjoc.15.155
Graphical Abstract
Scheme 1: Synthetic routes to O-thiocarbamates and dithiocarbamates.
Scheme 2: Substrate scope of isocyanides. aReaction conditions: 1 (1 mmol), S8 (2 mmol), 2a (2mmol), NaH (2 m...
Scheme 3: Substrate scope of alcohols. Reaction conditions: 1a (1 mmol), S8 (2 mmol), 2 (2mmol), NaH (2 mmol)...
Scheme 4: Substrate scope of thiols. Reaction conditions: 1a (1 mmol), S8 (1.2 mmol), 4 (2 mmol), NaOH (2 mmo...
Scheme 5: Scaled-up synthesis for 3a.
Scheme 6: Multicomponent domino synthesis of quinazolinone 7.
Scheme 7: Control experiments.
Scheme 8: Proposed mechanism.