Search for "isoquinolines" in Full Text gives 45 result(s) in Beilstein Journal of Organic Chemistry.
Beilstein J. Org. Chem. 2024, 20, 2722–2731, doi:10.3762/bjoc.20.230
Graphical Abstract
Figure 1: Selected natural products containing spiro-indolenines.
Scheme 1: Synthesis of spiro[indole-heterocycles].
Scheme 2: Synthetic strategy for the new synthesis of 2,3-diaminoindolenines [21] and spiro[indole-isoquinolines]....
Scheme 3: Scope of the synthesis of spiro[indole-THIQs]. aα-aminoamidine 2b has been isolated (54%) too; bα-a...
Scheme 4: Two-step synthesis using p-methylaniline.
Scheme 5: Investigation of the one-pot four-step synthetic protocol employing N-Ph-benzoxazepine 5.
Figure 2: Time profile of the reaction of N-Ph-THIQ, 3,5-dimethoxyaniline and t-BuNC conducted under optimize...
Scheme 6: Proposed mechanism.
Beilstein J. Org. Chem. 2024, 20, 1839–1879, doi:10.3762/bjoc.20.162
Graphical Abstract
Scheme 1: Mechanism of the GBB reaction.
Scheme 2: Comparison of the performance of Sc(OTf)3 with some RE(OTf)3 in a model GBB reaction. Conditions: a...
Scheme 3: Comparison of the performance of various Brønsted acid catalysts in the synthesis of GBB adduct 6. ...
Scheme 4: Synthesis of Brønsted acidic ionic liquid catalyst 7. Conditions: a) neat, 60 °C, 24 h; b) TfOH, DC...
Scheme 5: Aryliodonium derivatives as organic catalysts in the GBB reaction. In the box the proposed binding ...
Scheme 6: DNA-encoded GBB reaction in micelles made of amphiphilic polymer 13. Conditions: a) 13 (50 equiv), ...
Scheme 7: GBB reaction catalyzed by cyclodextrin derivative 14. Conditions: a) 14 (1 mol %), water, 100 °C, 4...
Scheme 8: Proposed mode of activation of CALB. a) activation of the substrates; b) activation of the imine; c...
Scheme 9: One-pot GBB reaction–Suzuki coupling with a bifunctional hybrid biocatalyst. Conditions: a) Pd(0)-C...
Scheme 10: GBB reaction employing 5-HMF (23) as carbonyl component. Conditions: a) TFA (20 mol %), EtOH, 60 °C...
Scheme 11: GBB reaction with β-C-glucopyranosyl aldehyde 26. Conditions: a) InCl3 (20 mol %), MeOH, 70 °C, 2–3...
Scheme 12: GBB reaction with diacetylated 5-formyldeoxyuridine 29, followed by deacetylation of GBB adduct 30....
Scheme 13: GBB reaction with glycal aldehydes 32. Conditions: a) HFIP, 25 °C, 2–4 h.
Scheme 14: Vilsmeier–Haack formylation of 6-β-acetoxyvouacapane (34) and subsequent GBB reaction. Conditions: ...
Scheme 15: GBB reaction of 4-formlyl-PCP 37. Conditions: a) HOAc or HClO4, MeOH/DCM (2:3), rt, 3 d.
Scheme 16: GBB reaction with HexT-aldehyde 39. Conditions: a) 39 (20 nmol) and amidine (20 μmol), MeOH, rt, 6 ...
Scheme 17: GBB reaction of 2,4-diaminopirimidine 41. Conditions: a) Sc(OTf)3 (20 mol %), MeCN, 120 °C (MW), 1 ...
Scheme 18: Synthesis of N-edited guanine derivatives from 3,6-diamine-1,2,4-triazin-5-one 44. Conditions: a) S...
Scheme 19: Synthesis of 2-aminoimidazoles 49 by a Mannich-3CR followed by a one-pot intramolecular oxidative a...
Scheme 20: On DNA Suzuki–Miyaura reaction followed by GBB reaction. Conditions: a) CsOH, sSPhos-Pd-G2; b) AcOH...
Scheme 21: One-pot cascade synthesis of 5-iminoimidazoles. Conditions: a) Na2SO4, DMF, 220 °C (MW).
Scheme 22: GBB reaction of 5-amino-1H-imidazole-4-carbonile 57. Conditions: a) HClO4 (5 mol %), MeOH, rt, 24 h....
Scheme 23: One-pot cascade synthesis of indole-imidazo[1,2,a]pyridine hybrids. In blue the structural motif in...
Scheme 24: One-pot cascade synthesis of fused polycyclic indoles 67 or 69 from indole-3-carbaldehyde. Conditio...
Scheme 25: One-pot cascade synthesis of linked- and bridged polycyclic indoles from indole-2-carbaldehyde (70)...
Scheme 26: One-pot cascade synthesis of pentacyclic dihydroisoquinolines (X = N or CH). In blue the structural...
Scheme 27: One-pot stepwise synthesis of imidazopyridine-fused benzodiazepines 85. Conditions: a) p-TsOH (20 m...
Scheme 28: One-pot stepwise synthesis of benzoxazepinium-fused imidazothiazoles 89. Conditions: a) Yb(OTf)3 (2...
Scheme 29: One-pot stepwise synthesis of fused imidazo[4,5,b]pyridines 95. Conditions: a) HClO4, MeOH, rt, ove...
Scheme 30: Synthesis of heterocyclic polymers via the GBB reaction. Conditions: a) p-TsOH, EtOH, 70 °C, 24 h.
Scheme 31: One-pot multicomponent reaction towards the synthesis of covalent organic frameworks via the GBB re...
Scheme 32: One-pot multicomponent reaction towards the synthesis of covalent organic frameworks via the GBB re...
Scheme 33: GBB-like multicomponent reaction towards the synthesis of benzothiazolpyrroles (X = S) and benzoxaz...
Scheme 34: GBB-like multicomponent reaction towards the formation of imidazo[1,2,a]pyridines. Conditions: a) I2...
Scheme 35: Post-functionalization of GBB products via Ugi reaction. Conditions a) HClO4, DMF, rt, 24 h; b) MeO...
Scheme 36: Post-functionalization of GBB products via Click reaction. Conditions: a) solvent-free, 150 °C, 24 ...
Scheme 37: Post-functionalization of GBB products via cascade alkyne–allene isomerization–intramolecular nucle...
Scheme 38: Post-functionalization of GBB products via metal-catalyzed intramolecular N-arylation. In red and b...
Scheme 39: Post-functionalization of GBB products via isocyanide insertion (X = N or CH). Conditions: a) HClO4...
Scheme 40: Post-functionalization of GBB products via intramolecular nucleophilic addition to nitriles. Condit...
Scheme 41: Post-functionalization of GBB products via Pictet–Spengler cyclization. Conditions: a) 4 N HCl/diox...
Scheme 42: Post-functionalization of GBB products via O-alkylation. Conditions: a) TFA (20 mol %), EtOH, 120 °...
Scheme 43: Post-functionalization of GBB products via macrocyclization (X = -CH2CH2O-, -CH2-, -(CH2)4-). Condi...
Figure 1: Antibacterial activity of GBB-Ugi adducts 113 on both Gram-negative and Gram-positive strains.
Scheme 44: GBB multicomponent reaction using trimethoprim as the precursor. Conditions: a) Yb(OTf)3 or Y(OTf)3...
Figure 2: Antibacterial activity of GBB adducts 152 against MRSA and VRE; NA = not available.
Figure 3: Antibacterial activity of GBB adduct 153 against Leishmania amazonensis promastigotes and amastigot...
Figure 4: Antiviral and anticancer evaluation of the GBB adducts 154a and 154b. In vitro antiproliferative ac...
Figure 5: Anticancer activity of the GBB-furoxan hybrids 145b, 145c and 145d determined through antiprolifera...
Scheme 45: Synthesis and anticancer activity of the GBB-gossypol conjugates. Conditions: a) Sc(OTf)3 (10 mol %...
Figure 6: Anticancer activity of polyheterocycles 133a and 136a against human neuroblastoma. Clonogenic assay...
Figure 7: Development of GBB-adducts 158a and 158b as PD-L1 antagonists. HTRF assays were carried out against...
Figure 8: Development of imidazo[1,2-a]pyridines and imidazo[1,2-a]pyrazines as TDP1 inhibitors. The SMM meth...
Figure 9: GBB adducts 164a–c as anticancer through in vitro HDACs inhibition assays. Additional cytotoxic ass...
Figure 10: GBB adducts 165, 166a and 166b as anti-inflammatory agents through HDAC6 inhibition; NA = not avail...
Scheme 46: GBB reaction of triphenylamine 167. Conditions: a) NH4Cl (10 mol %), MeOH, 80 °C (MW), 1 h.
Scheme 47: 1) Modified GBB-3CR. Conditions: a) TMSCN (1.0 equiv), Sc(OTf)3 (0.2 equiv), MeOH, 140 °C (MW), 20 ...
Scheme 48: GBB reaction to assemble imidazo-fused heterocycle dimers 172. Conditions: a) Sc(OTf)3 (20 mol %), ...
Figure 11: Model compounds 173 and 174, used to study the acid/base-triggered reversible fluorescence response...
Beilstein J. Org. Chem. 2024, 20, 1436–1443, doi:10.3762/bjoc.20.126
Graphical Abstract
Figure 1: Molecular structure of compound 4a.
Figure 2: Molecular structure of compound 6g.
Scheme 1: Proposed reaction mechanism.
Beilstein J. Org. Chem. 2023, 19, 1677–1693, doi:10.3762/bjoc.19.123
Graphical Abstract
Figure 1: Classification of AMYs.
Scheme 1: Aminoester- and amino acid-based AMYs for single and double [3+2] cycloadditions.
Scheme 2: Formation of semi-stabilized AMYs B1 from pyrrolidines.
Scheme 3: Cyclic amine-based AMYs A3 and B1 for [3 + 2] cycloadditions.
Scheme 4: Proposed double cycloaddition reactions involving semi-stabilized AMYs.
Scheme 5: [3 + 2] Cycloaddition for the synthesis of trifluoromethylated pyrrolidines 9.
Figure 2: Biologically interesting pyrrolizidines.
Scheme 6: Double cycloadditions with glycine for the synthesis of products 10 (dr > 9:1).
Scheme 7: Double cycloadditions with α-substituted amino acids leading to products 11 (≈8.5:1 dr).
Scheme 8: Stereochemistry for the formation of products 10 or 11.
Scheme 9: One-pot and stepwise double cycloadditions. Conditions: i) MeCN (0.02 M), 90 °C, 6 h; ii) then AcOH...
Figure 3: Biologically interesting spirooxindole-pyrrolizidines.
Scheme 10: Double cycloadditions for the synthesis of bis[spirooxindole-pyrrolizidine]s.
Scheme 11: Mechanism for the diastereoselective synthesis of bis[spirooxindole-pyrrolizidine]s.
Scheme 12: Stepwise synthesis of triazolobenzodiazepine 21a.
Scheme 13: One-pot synthesis of triazolobenzodiazepines.
Figure 4: Bioactive triazolobenzodiazepine derivatives.
Scheme 14: One-pot synthesis of tetrahydropyrroloquinazolines.
Scheme 15: One-pot synthesis of tetrahydropyrrolobenzodiazepines.
Figure 5: Bioactive pyrroloquinazolines and pyrrolobenzodiazepines.
Scheme 16: Stepwise synthesis of pyrrolo[2,1-a]isoquinolines.
Figure 6: Bioactive pyrrolo[2,1-a]isoquinolines and hexahydropyrrolo[2,1-a]isoquinolines.
Figure 7: Bioactive tetrahydropyrrolothiazoles.
Scheme 17: Pseudo-four-component reaction for the synthesis of tetrahydropyrrolothiazoles 29 and 30 (>4:1 dr).
Scheme 18: One-pot two-step synthesis of spirooxindole-pyrrolothiazoles 31 (>4:1 dr).
Beilstein J. Org. Chem. 2023, 19, 1259–1288, doi:10.3762/bjoc.19.94
Graphical Abstract
Scheme 1: Research progress of coupling reactions and active compounds containing α-C(sp3)-functionalized eth...
Scheme 2: Transition-metal-catalyzed CDC pathways.
Scheme 3: CDC of active methylene compounds in the α-C(sp3) position of ethers.
Scheme 4: InCl3/Cu(OTf)2/NHPI co-catalyzed CDC reaction.
Scheme 5: CDC of cyclic benzyl ethers with aldehydes.
Scheme 6: Cu-catalyzed CDC of (a) unactivated C(sp3)–H ethers with simple ketones and (b) double C(sp3)−H fun...
Scheme 7: Cu-catalyzed CDC of C(sp3)–H/C(sp3)–H bonds.
Scheme 8: Cu-catalyzed synthesis of chiral 2-substituted tetrahydropyrans.
Scheme 9: CDC of thiazole with cyclic ethers.
Scheme 10: Cu(I)-catalyzed oxidative alkenylation of simple ethers.
Scheme 11: Cross-dehydrogenation coupling of isochroman C(sp3)–H bonds with anisole C(sp2)–H bonds.
Scheme 12: Pd(OAc)2/Cu(OTf)2-catalyzed arylation of α-C(sp3)–H bonds of ethers.
Scheme 13: Cu-catalyzed C(sp3)–H/C(sp2)–H activation strategies to construct C(sp3)–C(sp2) bonds.
Scheme 14: Cu(I)-catalyzed C(sp2)–H alkylation.
Scheme 15: Cu-catalyzed C(sp3)–H/C(sp)–H activation to construct C(sp3)–C(sp) bonds (H2BIP: 2,6-bis(benzimidaz...
Scheme 16: Fe-catalyzed CDC reaction pathways.
Scheme 17: Fe2(CO)9-catalyzed functionalization of C–H bonds.
Scheme 18: Ligand-promoted Fe-catalyzed CDC reaction of N-methylaniline with ethers.
Scheme 19: Fe-catalyzed CDC of C(sp3)–H/C(sp3)–H bonds.
Scheme 20: Fe-catalyzed hydroalkylation of α,β-unsaturated ketones with ethers.
Scheme 21: Solvent-free Fe(NO3)3-catalyzed CDC of C(sp3)–H/C(sp2)–H bonds.
Scheme 22: Alkylation of disulfide compounds to afford tetrasubstituted alkenes.
Scheme 23: Fe-catalyzed formation of 1,1-bis-indolylmethane derivatives.
Scheme 24: Alkylation of coumarins and flavonoids.
Scheme 25: Direct CDC α-arylation of azoles with ethers.
Scheme 26: CDC of terminal alkynes with C(sp3)–H bonds adjacent to oxygen, sulfur or nitrogen atoms.
Scheme 27: Alkylation of terminal alkynes.
Scheme 28: Co-catalyzed functionalization of glycine esters.
Scheme 29: Co-catalyzed construction of C(sp2)–C(sp3) bonds.
Scheme 30: Co-catalyzed CDC of imidazo[1,2-a]pyridines with isochroman.
Scheme 31: Co-catalyzed C–H alkylation of (benz)oxazoles with ethers.
Scheme 32: Cobalt-catalyzed CDC between unactivated C(sp2)–H and C(sp3)–H bonds.
Scheme 33: MnO2-catalyzed CDC of the inactive C(sp3)-H.
Scheme 34: Oxidative cross-coupling of ethers with enamides.
Scheme 35: Ni(II)-catalyzed CDC of indoles with 1,4-dioxane.
Scheme 36: Chemo- and regioselective ortho- or para-alkylation of pyridines.
Scheme 37: Asymmetric CDC of 3,6-dihydro-2H-pyrans with aldehydes.
Scheme 38: CDC of heterocyclic aromatics with ethers.
Scheme 39: Indium-catalyzed alkylation of DHPs with 1,3-dicarbonyl compounds.
Scheme 40: Rare earth-metal-catalyzed CDC reaction.
Scheme 41: Visible-light-driven CDC of cycloalkanes with benzazoles.
Scheme 42: Photoinduced alkylation of quinoline with cyclic ethers.
Scheme 43: Photocatalyzed CDC reactions between α-C(sp3)–H bonds of ethers and C(sp2)–H bonds of aromatics.
Beilstein J. Org. Chem. 2023, 19, 1055–1145, doi:10.3762/bjoc.19.81
Graphical Abstract
Figure 1: Oxidative and reductive activations of organic compounds harvesting photoredox catalysis.
Figure 2: General catalytic cycles of radical ion conPET (left) and radical ion e-PRC (right).
Figure 3: “Beginner’s guide”: comparison between advantages, capacities, and prospectives of conPET and PEC.
Figure 4: A) conPET reductive dehalogenation of aryl halides with PDI. B) Reductive C–H arylation with pyrrol...
Figure 5: A) Chromoselective mono- and disubstitution or polybrominated pyrimidines with pyrroles. B) Sequent...
Figure 6: A) Synthesis of pyrrolo[1,2-a]quinolines. B) Synthesis of ullazines.
Figure 7: A) Reductive phosphorylation of aryl halides via conPET. B) Selected examples from the substrate sc...
Figure 8: A) Reductive dehalogenation of aryl halides via conPET and selected examples from the substrate sco...
Figure 9: A) Reductive C–H arylation of aryl halides via conPET (top) and selected examples from the substrat...
Figure 10: A) Reductive hydrodehalogenation of aryl halides with Mes-Acr-BF4. B) Selected examples from the su...
Figure 11: A) Reductive hydrodechlorination of aryl chlorides with 4-DPAIPN. B) Proposed formation of CO2•−. C...
Figure 12: A) Reductive conPET borylation with 3CzEPAIPN (top) and selected examples from the substrate scope ...
Figure 13: Scale-up of conPET phosphorylation with 3CzEPAIPN.
Figure 14: A) Borylation of 1d. B) Characteristics and structure of PC1 with green and red parts showing the l...
Figure 15: A) Reductive C–H arylation scope with polysulfide conPET (top) and selected examples from the subst...
Figure 16: Scale-up of A) C–H arylation and B) dehaloborylation with polysulfide photocatalysis in continuous-...
Figure 17: A) Formation of [Ir1]0 and [Ir2]0 upon PET between [Ir1]+ and Et3N. B) Mechanism of multi-photon ta...
Figure 18: A) Reductive hydrodehalogenation of aryl halides via multi-photon tandem photocatalysis. B) Selecte...
Figure 19: A) Carbonylative amidation of aryl halides in continuous flow. B) Selected examples from the substr...
Figure 20: A) General scheme for reductive (RQ) and oxidative quenching (OQ) protocols using [FeIII(btz)3](PF6)...
Figure 21: A) Carbonylative amidation of alkyl iodides with [IrIII(ppy)2(dtbbpy)]PF6. B) Selected examples fro...
Figure 22: A) Carboxylative C–N bond cleavage in cyclic amines. B) Selected examples from the substrate scope....
Figure 23: A) Formal reduction of alkenes to alkanes via transfer hydrogenation. B) Selected examples from the...
Figure 24: A) Birch-type reduction of benzenes with PMP-BPI. B) Selected examples from the substrate scope (sc...
Figure 25: Proposed mechanism of the OH− mediated conPET Birch-type reduction of benzene via generation of sol...
Figure 26: Reductive detosylation of N-tosylated amides with Mes-Acr-BF4. B) Selected examples from the substr...
Figure 27: A) Reductive detosylation of N-tosyl amides by dual PRC. B) Selected examples from the substrate sc...
Figure 28: A) Mechanism of the dual PRC based on PET between [Cu(dap)2]+ and DCA. B) Mechanism of the dual PRC...
Figure 29: A) N–O bond cleavage in Weinreb amides with anthracene. B) N–O bond cleavage in Weinreb amides rely...
Figure 30: A) Pentafluorosulfanylation and fluoride elimination. B) Mechanism of the pentafluorosulfanylation ...
Figure 31: A) α-Alkoxypentafluorosulfanylation (top) and selected examples from the substrate scope (bottom). ...
Figure 32: A) Oxidative amination of arenes with azoles catalyzed by N-Ph PTZ. B) Selected examples from the s...
Figure 33: A) C(sp3)–H bond activation by HAT via chloride oxidation by *N-Ph PTZ•+. B) Proposed mechanism for...
Figure 34: A) Recycling e-PRC C–H azolation of electron-rich arenes with pyrazoles using Mes-Acr+ as a photoca...
Figure 35: A) Radical ion e-PRC direct oxidation of unactivated arenes using TAC+ as an electro-activated phot...
Figure 36: A) Radical ion e-PRC direct oxidation of unactivated arenes using TPA as an electro-activated photo...
Figure 37: Proposed mechanism (top) and mode of preassembly (bottom).
Figure 38: A) Possible preassemblies of reactive (left) vs unreactive (right) arenes. B) Calculated spin densi...
Figure 39: A) Recycling e-PRC C(sp2 )–H acetoxylation of arenes using DDQ as a photocatalyst. B) Proposed cata...
Figure 40: Gram scale hydroxylation of benzene in a recirculated flow setup.
Figure 41: A) Radical ion e-PRC vicinal diamination of alkylarenes using TAC+ as an electro-activated photocat...
Figure 42: A) Sequential oxygenation of multiple adjacent C–H bonds under radical ion e-PRC using TAC+ as an e...
Figure 43: A) Enantioselective recycling e-PRC cyanation of benzylic C–H bonds using ADQS as photocatalyst. B)...
Figure 44: Proposed tandem mechanism by Xu and co-workers.
Figure 45: A) Enantioselective recycling e-PRC decarboxylative cyanation using Cu(acac)2, Ce(OTf)3 and a box l...
Figure 46: A) Enantioselective recycling e-PRC benzylic cyanation using Cu(MeCN)4BF4, box ligand and anthraqui...
Figure 47: A) Radical ion e-PRC acetoxyhydroxylation of aryl olefins using TAC+ as an electro-activated photoc...
Figure 48: Selected examples from the substrate scope.
Figure 49: Photoelectrochemical acetoxyhydroxylation in a recirculated flow setup.
Figure 50: A) Radical ion e-PRC aminooxygenation of aryl olefins using TAC+ as an electro-activated photocatal...
Figure 51: A) Recycling e-PRC C–H alkylation of heteroarenes with organic trifluoroborates using Mes-Acr+ as p...
Figure 52: A) Recycling e-PRC decarboxylative C–H alkylation of heteroarenes using CeCl3·7H2O as catalyst. B) ...
Figure 53: A) Recycling e-PRC decarboxylative C–H alkylation of heteroarenes using Fe(NH4)2(SO4)2·6H2O as cata...
Figure 54: A) Recycling e-PRC C–H alkylation of heteroarenes with alkyl oxalates and 4CzIPN as photocatalyst. ...
Figure 55: A) Recycling e-PRC decarboxylative C–H carbamoylation of heteroarenes using 4CzIPN as photocatalyst...
Figure 56: A) Photoelectrochemical HAT-mediated hydrocarbon activation via the chlorine radical. B) Proposed m...
Figure 57: A) Selected examples from the substrate scope. B) Gram and decagram scale semi-continuous flow PEC ...
Figure 58: A) Photoelectrochemical HAT-mediated dehydrogenative coupling of benzothiazoles with aliphatic C–H ...
Figure 59: A) Photoelectrochemical HAT activation of ethers using electro-activated TAC+ as photocatalyst. B) ...
Figure 60: Selected examples from the substrate scope.
Figure 61: A) Photoelectrochemical HAT-mediated synthesis of alkylated benzimidazo-fused isoquinolinones using...
Figure 62: A) Decoupled photoelectrochemical cerium-catalyzed oxydichlorination of alkynes using CeCl3 as cata...
Figure 63: Proposed decoupled photoelectrochemical mechanism.
Figure 64: A) Decoupled photoelectrochemical ring-opening bromination of tertiary cycloalkanols using MgBr2 as...
Figure 65: A) Recycling e-PRC ring-opening functionalization of cycloalkanols using CeCl3 as catalyst. B) Prop...
Figure 66: Selected examples from the substrate scope of the PEC ring-opening functionalization.
Figure 67: A) Radical ion e-PRC reduction of chloro- and bromoarenes using DCA as catalyst and various accepto...
Figure 68: A) Screening of different phthalimide derivatives as catalyst for the e-PRC reduction of aryl halid...
Figure 69: Screening of different organic catalysts for the e-PRC reduction of trialkylanilium salts.
Figure 70: A) e-PRC reduction of phosphonated phenols and anilinium salts. B) Selected examples from the subst...
Figure 71: A) ConPET and e-PRC reduction of 4-bromobenzonitrile using a naphthalene diimide (NDI) precatalyst ...
Figure 72: A) Radical ion e-PRC reduction of phosphinated aliphatic alcohols with n-BuO-NpMI as catalyst. B) C...
Figure 73: Selected examples from the substrate scope.
Figure 74: A) Recycling e-PRC reductive dimerization of benzylic chlorides using a [Cu2] catalyst. B) Proposed...
Figure 75: A) Decoupled photoelectrochemical C–H alkylation of heteroarenes through deamination of Katritzky s...
Figure 76: Proposed mechanism by Chen and co-workers.
Beilstein J. Org. Chem. 2023, 19, 982–990, doi:10.3762/bjoc.19.73
Graphical Abstract
Scheme 1: Various cycloaddition reactions of 5,6-unsymmetric 1,4-dihydropyridines.
Figure 1: Single crystal structure of the compound 4k.
Figure 2: Single crystal structure of compound 5a.
Figure 3: Single crystal structure of compound 6f.
Scheme 2: Plausible reaction mechanism for the various products 4, 5, and 6.
Beilstein J. Org. Chem. 2023, 19, 820–863, doi:10.3762/bjoc.19.62
Graphical Abstract
Figure 1: Representative examples of bioactive natural products and FDA-approved drugs containing a pyridine ...
Scheme 1: Classical and traditional methods for the synthesis of functionalized pyridines.
Scheme 2: Rare earth metal (Ln)-catalyzed pyridine C–H alkylation.
Scheme 3: Pd-catalyzed C–H alkylation of pyridine N-oxide.
Scheme 4: CuI-catalyzed C–H alkylation of N-iminopyridinium ylides with tosylhydrazones (A) and a plausible r...
Scheme 5: Zirconium complex-catalyzed pyridine C–H alkylation.
Scheme 6: Rare earth metal-catalyzed pyridine C–H alkylation with nonpolar unsaturated substrates.
Scheme 7: Heterobimetallic Rh–Al complex-catalyzed ortho-C–H monoalkylation of pyridines.
Scheme 8: Mono(phosphinoamido)-rare earth complex-catalyzed pyridine C–H alkylation.
Scheme 9: Rhodium-catalyzed pyridine C–H alkylation with acrylates and acrylamides.
Scheme 10: Ni–Al bimetallic system-catalyzed pyridine C–H alkylation.
Scheme 11: Iridium-catalyzed pyridine C–H alkylation.
Scheme 12: para-C(sp2)–H Alkylation of pyridines with alkenes.
Scheme 13: Enantioselective pyridine C–H alkylation.
Scheme 14: Pd-catalyzed C2-olefination of pyridines.
Scheme 15: Ru-catalyzed C-6 (C-2)-propenylation of 2-arylated pyridines.
Scheme 16: C–H addition of allenes to pyridines catalyzed by half-sandwich Sc metal complex.
Scheme 17: Pd-catalyzed stereodivergent synthesis of alkenylated pyridines.
Scheme 18: Pd-catalyzed ligand-promoted selective C3-olefination of pyridines.
Scheme 19: Mono-N-protected amino acids in Pd-catalyzed C3-alkenylation of pyridines.
Scheme 20: Amide-directed and rhodium-catalyzed C3-alkenylation of pyridines.
Scheme 21: Bimetallic Ni–Al-catalyzed para-selective alkenylation of pyridine.
Scheme 22: Arylboronic ester-assisted pyridine direct C–H arylation.
Scheme 23: Pd-catalyzed C–H arylation/benzylation with toluene.
Scheme 24: Pd-catalyzed pyridine C–H arylation with potassium aryl- and heteroaryltrifluoroborates.
Scheme 25: Transient activator strategy in pyridine C–H biarylation.
Scheme 26: Ligand-promoted C3-arylation of pyridine.
Scheme 27: Pd-catalyzed arylation of nicotinic and isonicotinic acids.
Scheme 28: Iron-catalyzed and imine-directed C–H arylation of pyridines.
Scheme 29: Pd–(bipy-6-OH) cooperative system-mediated direct pyridine C3-arylation.
Scheme 30: Pd-catalyzed pyridine N-oxide C–H arylation with heteroarylcarboxylic acids.
Scheme 31: Pd-catalyzed C–H cross-coupling of pyridine N-oxides with five-membered heterocycles.
Scheme 32: Cu-catalyzed dehydrative biaryl coupling of azine(pyridine) N-oxides and oxazoles.
Scheme 33: Rh(III)-catalyzed cross dehydrogenative C3-heteroarylation of pyridines.
Scheme 34: Pd-catalyzed C3-selective arylation of pyridines.
Scheme 35: Rhodium-catalyzed oxidative C–H annulation of pyridines to quinolines.
Scheme 36: Rhodium-catalyzed and NHC-directed C–H annulation of pyridine.
Scheme 37: Ni/NHC-catalyzed regio- and enantioselective C–H cyclization of pyridines.
Scheme 38: Rare earth metal-catalyzed intramolecular C–H cyclization of pyridine to azaindolines.
Scheme 39: Rh-catalyzed alkenylation of bipyridine with terminal silylacetylenes.
Scheme 40: Rollover cyclometallation in Rh-catalyzed pyridine C–H functionalization.
Scheme 41: Rollover pathway in Rh-catalyzed C–H functionalization of N,N,N-tridentate chelating compounds.
Scheme 42: Pd-catalyzed rollover pathway in bipyridine-6-carboxamides C–H arylation.
Scheme 43: Rh-catalyzed C3-acylmethylation of bipyridine-6-carboxamides with sulfoxonium ylides.
Scheme 44: Rh-catalyzed C–H functionalization of bipyridines with alkynes.
Scheme 45: Rh-catalyzed C–H acylmethylation and annulation of bipyridine with sulfoxonium ylides.
Scheme 46: Iridium-catalyzed C4-borylation of pyridines.
Scheme 47: C3-Borylation of pyridines.
Scheme 48: Pd-catalyzed regioselective synthesis of silylated dihydropyridines.
Beilstein J. Org. Chem. 2021, 17, 2765–2772, doi:10.3762/bjoc.17.186
Graphical Abstract
Figure 1: Biologically active 1-aminoisoquinolines.
Scheme 1: Comparison of our work with the previous approaches for the synthesis of 1-aminoisoquinolines.
Scheme 2: Substrate scope of anilines for the synthesis of 1-aminoisoquinolines (5a–m). Reaction conditions: 3...
Scheme 3: Substrate scope of 2-(2-oxo-2-phenylethyl)benzonitrile (3b–e) for the synthesis of 1-aminoisoquinol...
Scheme 4: Substrate scope of aliphatic amines for the synthesis of 1-aminoisoquinolines (5v–x), gram-scale sy...
Scheme 5: Proposed mechanism for the synthesis of 1-aminoisoquinoline 5a.
Beilstein J. Org. Chem. 2021, 17, 2462–2476, doi:10.3762/bjoc.17.163
Graphical Abstract
Scheme 1: Ag/I2-mediated electrophilic annulation of 2-en-4-ynyl azides 1.
Scheme 2: The proposed mechanism of Ag-catalyzed aza-annulation.
Scheme 3: The proposed mechanism of I2-mediated aza-annulation.
Scheme 4: Copper-catalyzed amination of (E)-2-en-4-ynyl azides 1.
Scheme 5: The proposed mechanism of copper-catalyzed amination.
Scheme 6: The derivatization of sulfonated aminonicotinates.
Scheme 7: Copper-catalyzed chalcogenoamination of (E)-2-en-4-ynyl azides 1.
Scheme 8: The possible mechanism of chalcogenoamination.
Scheme 9: The derivatization of 5‑selenyl- and 5-sulfenyl-substituted nicotinates.
Scheme 10: The tandem reaction of nitriles, Reformatsky reagents, and 1,3-enynes.
Scheme 11: Nickel-catalyzed [4 + 2]-cycloaddition of 3-azetidinones with 1,3-enynes.
Scheme 12: Electrophilic iodocyclization of 2-nitro-1,3-enynes to pyrroles.
Scheme 13: Electrophilic halogenation of 2-trifluoromethyl-1,3-enynes to pyrroles.
Scheme 14: Copper-catalyzed cascade cyclization of 2-nitro-1,3-enynes with amines.
Scheme 15: Tandem cyclization of 2-nitro-1,3-enynes, Togni reagent II, and amines.
Scheme 16: Tandem cyclization of 2-nitro-1,3-enynes, TMSN3, and amines.
Scheme 17: Cascade cyclization of 6-hydroxyhex-2-en-4-ynals to pyrroles.
Scheme 18: Au/Ag-catalyzed oxidative aza-annulation of 1,3-enynyl azides.
Scheme 19: The plausible mechanism of Au/Ag-catalyzed oxidative aza-annulation.
Scheme 20: Synthesis of 2-tetrazolyl-substituted 3-acylpyrroles from enynals.
Scheme 21: CuH-catalyzed coupling reaction of 1,3-enynes and nitriles to pyrroles.
Scheme 22: The mechanism of CuH-catalyzed coupling of 1,3-enynes and nitriles to pyrroles.
Beilstein J. Org. Chem. 2021, 17, 2270–2286, doi:10.3762/bjoc.17.145
Graphical Abstract
Figure 1: a) Binding interactions in the chloride channel of E. coli. and b) examples of chloride, cyanide, n...
Figure 2: a) H-bond vs anion-binding catalysis and b) activation modes in anion-binding catalysis.
Scheme 1: First proposed anion-binding mechanism in the thiourea-catalyzed acetalization of benzaldehyde.
Scheme 2: a) Thiourea-catalyzed enantioselective acyl-Pictet–Spengler reaction of tryptamine-derived imines 4...
Scheme 3: Proposed mechanism of the thiourea-catalyzed enantioselective Pictet–Spengler reaction of hydroxyla...
Scheme 4: a) Thiourea-catalyzed intramolecular Pictet–Spengler-type cyclization of hydroxylactam-derived N-ac...
Scheme 5: Enantioselective Reissert-type reactions of a) (iso)quinolines with silyl ketene acetals, and b) vi...
Figure 3: Role of the counter-anion: a) Anion acting as a spectator and b) anion participating directly as th...
Scheme 6: Enantioselective selenocyclization catalyzed by squaramide 28.
Scheme 7: Desymmetrization of meso-aziridines catalyzed by bifunctional thiourea catalyst 31.
Scheme 8: Anion-binding-catalyzed desymmetrization of a) meso-aziridines catalyzed by chiral triazolium catal...
Scheme 9: Bis-urea-catalyzed enantioselective fluorination of a) β-bromosulfides and b) β-haloamines by Gouve...
Scheme 10: a) Bifunctional thiourea anion-binding – basic/nucleophilic catalysts. Selected applications in b) ...
Scheme 11: Thiourea-catalyzed enantioselective polycyclization reaction of hydroxylactams 51 through cation–π ...
Scheme 12: Enantioselective aza-Sakurai cyclization of hydroxylactams 56 implicating additional cation–π and L...
Scheme 13: Enantioselective tail-to-head cyclization of neryl chloride derivatives.
Scheme 14: Cation–π interactions in anion binding-catalyzed asymmetric addition reactions: a) addition of indo...
Scheme 15: Bisthiourea catalyzed oxa-Pictet–Spengler reaction of indole-based alcohols and aromatic aldehydes ...
Scheme 16: Anion-binding catalyst development in the enantioselective addition of silyl ketene acetals to 1-ch...
Scheme 17: a) Macrocyclic bis-thiourea catalyst in a diastereoselective glycosylation reaction. b) Competing SN...
Scheme 18: a) Folding mechanism of oligotriazoles upon anion recognition. b) Representative tetratriazole 82 c...
Scheme 19: Switchable chiral tetratriazole catalyst 86 in the enantioselective addition of silyl ketene acetal...
Beilstein J. Org. Chem. 2021, 17, 1849–1938, doi:10.3762/bjoc.17.126
Graphical Abstract
Scheme 1: Schematic overview of transition metals studied in C–H activation processes.
Scheme 2: (A) Known biological activities related to benzimidazole-based compounds; (B and C) an example of a...
Scheme 3: (A) Known biological activities related to quinoline-based compounds; (B and C) an example of a sca...
Scheme 4: (A) Known biological activities related to sulfur-containing compounds; (B and C) an example of a s...
Scheme 5: (A) Known biological activities related to aminoindane derivatives; (B and C) an example of a scand...
Scheme 6: (A) Known biological activities related to norbornane derivatives; (B and C) an example of a scandi...
Scheme 7: (A) Known biological activities related to aniline derivatives; (B and C) an example of a titanium-...
Scheme 8: (A) Known biological activities related to cyclohexylamine derivatives; (B) an example of an intram...
Scheme 9: (A) Known biologically active benzophenone derivatives; (B and C) photocatalytic oxidation of benzy...
Scheme 10: (A) Known bioactive fluorine-containing compounds; (B and C) vanadium-mediated C(sp3)–H fluorinatio...
Scheme 11: (A) Known biologically active Lythraceae alkaloids; (B) synthesis of (±)-decinine (30).
Scheme 12: (A) Synthesis of (R)- and (S)-boehmeriasin (31); (B) synthesis of phenanthroindolizidines by vanadi...
Scheme 13: (A) Known bioactive BINOL derivatives; (B and C) vanadium-mediated oxidative coupling of 2-naphthol...
Scheme 14: (A) Known antiplasmodial imidazopyridazines; (B) practical synthesis of 41.
Scheme 15: (A) Gold-catalyzed drug-release mechanism using 2-alkynylbenzamides; (B and C) chromium-mediated al...
Scheme 16: (A) Examples of anti-inflammatory benzaldehyde derivatives; (B and C) chromium-mediated difunctiona...
Scheme 17: (A and B) Manganese-catalyzed chemoselective intramolecular C(sp3)–H amination; (C) late-stage modi...
Scheme 18: (A and B) Manganese-catalyzed C(sp3)–H amination; (C) late-stage modification of a leelamine deriva...
Scheme 19: (A) Known bioactive compounds containing substituted N-heterocycles; (B and C) manganese-catalyzed ...
Scheme 20: (A) Known indoles that present GPR40 full agonist activity; (B and C) manganese-catalyzed C–H alkyl...
Scheme 21: (A) Examples of known biaryl-containing drugs; (B and C) manganese-catalyzed C–H arylation through ...
Scheme 22: (A) Known zidovudine derivatives with potent anti-HIV properties; (B and C) manganese-catalyzed C–H...
Scheme 23: (A and B) Manganese-catalyzed C–H organic photo-electrosynthesis; (C) late-stage modification.
Scheme 24: (A) Example of a known antibacterial silylated dendrimer; (B and C) manganese-catalyzed C–H silylat...
Scheme 25: (A and B) Fe-based small molecule catalyst applied for selective aliphatic C–H oxidations; (C) late...
Scheme 26: (A) Examples of naturally occurring gracilioethers; (B) the first total synthesis of gracilioether ...
Scheme 27: (A and B) Selective aliphatic C–H oxidation of amino acids; (C) late-stage modification of proline-...
Scheme 28: (A) Examples of Illicium sesquiterpenes; (B) first chemical synthesis of (+)-pseudoanisatin (80) in...
Scheme 29: (A and B) Fe-catalyzed deuteration; (C) late-stage modification of pharmaceuticals.
Scheme 30: (A and B) Biomimetic Fe-catalyzed aerobic oxidation of methylarenes to benzaldehydes (PMHS, polymet...
Scheme 31: (A) Known tetrahydroquinolines with potential biological activities; (B and C) redox-selective Fe c...
Scheme 32: (A) Known drugs containing a benzofuran unit; (B and C) Fe/Cu-catalyzed tandem O-arylation to acces...
Scheme 33: (A) Known azaindolines that act as M4 muscarinic acetylcholine receptor agonists; (B and C) intramo...
Scheme 34: (A) Known indolinones with anticholinesterase activity; (B and C) oxidative C(sp3)–H cross coupling...
Scheme 35: (A and B) Cobalt-catalyzed C–H alkenylation of C-3-peptide-containing indoles; (C) derivatization b...
Scheme 36: (A) Cobalt-Cp*-catalyzed C–H methylation of known drugs; (B and C) scope of the o-methylated deriva...
Scheme 37: (A) Known lasalocid A analogues; (B and C) three-component cobalt-catalyzed C–H bond addition; (D) ...
Scheme 38: (A and B) Cobalt-catalyzed C(sp2)–H amidation of thiostrepton.
Scheme 39: (A) Known 4H-benzo[d][1,3]oxazin-4-one derivatives with hypolipidemic activity; (B and C) cobalt-ca...
Scheme 40: (A and B) Cobalt-catalyzed C–H arylation of pyrrole derivatives; (C) application for the synthesis ...
Scheme 41: (A) Known 2-phenoxypyridine derivatives with potent herbicidal activity; (B and C) cobalt-catalyzed...
Scheme 42: (A) Natural cinnamic acid derivatives; (B and C) cobalt-catalyzed C–H carboxylation of terminal alk...
Scheme 43: (A and B) Cobalt-catalyzed C–H borylation; (C) application to the synthesis of flurbiprofen.
Scheme 44: (A) Benzothiazoles known to present anticonvulsant activities; (B and C) cobalt/ruthenium-catalyzed...
Scheme 45: (A and B) Cobalt-catalyzed oxygenation of methylene groups towards ketone synthesis; (C) synthesis ...
Scheme 46: (A) Known anticancer tetralone derivatives; (B and C) cobalt-catalyzed C–H difluoroalkylation of ar...
Scheme 47: (A and B) Cobalt-catalyzed C–H thiolation; (C) application in the synthesis of quetiapine (153).
Scheme 48: (A) Known benzoxazole derivatives with anticancer, antifungal, and antibacterial activities; (B and...
Scheme 49: (A and B) Cobalt-catalyzed C–H carbonylation of naphthylamides; (C) BET inhibitors 158 and 159 tota...
Scheme 50: (A) Known bioactive pyrrolo[1,2-a]quinoxalin-4(5H)-one derivatives; (B and C) cobalt-catalyzed C–H ...
Scheme 51: (A) Known antibacterial cyclic sulfonamides; (B and C) cobalt-catalyzed C–H amination of propargyli...
Scheme 52: (A and B) Cobalt-catalyzed intramolecular 1,5-C(sp3)–H amination; (C) late-stage functionalization ...
Scheme 53: (A and B) Cobalt-catalyzed C–H/C–H cross-coupling between benzamides and oximes; (C) late-state syn...
Scheme 54: (A) Known anticancer natural isoquinoline derivatives; (B and C) cobalt-catalyzed C(sp2)–H annulati...
Scheme 55: (A) Enantioselective intramolecular nickel-catalyzed C–H activation; (B) bioactive obtained motifs;...
Scheme 56: (A and B) Nickel-catalyzed α-C(sp3)–H arylation of ketones; (C) application of the method using kno...
Scheme 57: (A and B) Nickel-catalyzed C(sp3)–H acylation of pyrrolidine derivatives; (C) exploring the use of ...
Scheme 58: (A) Nickel-catalyzed C(sp3)–H arylation of dioxolane; (B) library of products obtained from biologi...
Scheme 59: (A) Intramolecular enantioselective nickel-catalyzed C–H cycloalkylation; (B) product examples, inc...
Scheme 60: (A and B) Nickel-catalyzed C–H deoxy-arylation of azole derivatives; (C) late-stage functionalizati...
Scheme 61: (A and B) Nickel-catalyzed decarbonylative C–H arylation of azole derivatives; (C) application of t...
Scheme 62: (A and B) Another important example of nickel-catalyzed C–H arylation of azole derivatives; (C) app...
Scheme 63: (A and B) Another notable example of a nickel-catalyzed C–H arylation of azole derivatives; (C) lat...
Scheme 64: (A and B) Nickel-based metalorganic framework (MOF-74-Ni)-catalyzed C–H arylation of azole derivati...
Scheme 65: (A) Known commercially available benzothiophene-based drugs; (B and C) nickel-catalyzed C–H arylati...
Scheme 66: (A) Known natural tetrahydrofuran-containing substances; (B and C) nickel-catalyzed photoredox C(sp3...
Scheme 67: (A and B) Another notable example of a nickel-catalyzed photoredox C(sp3)–H alkylation/arylation; (...
Scheme 68: (A) Electrochemical/nickel-catalyzed C–H alkoxylation; (B) achieved scope, including three using na...
Scheme 69: (A) Enantioselective photoredox/nickel catalyzed C(sp3)–H arylation; (B) achieved scope, including ...
Scheme 70: (A) Known commercially available trifluoromethylated drugs; (B and C) nickel-catalyzed C–H trifluor...
Scheme 71: (A and B) Stereoselective nickel-catalyzed C–H difluoroalkylation; (C) late-stage functionalization...
Scheme 72: (A) Cu-mediated ortho-amination of oxalamides; (B) achieved scope, including derivatives obtained f...
Scheme 73: (A) Electro-oxidative copper-mediated amination of 8-aminoquinoline-derived amides; (B) achieved sc...
Scheme 74: (A and B) Cu(I)-mediated C–H amination with oximes; (C) derivatization using telmisartan (241) as s...
Scheme 75: (A and B) Cu-mediated amination of aryl amides using ammonia; (C) late-stage modification of proben...
Scheme 76: (A and B) Synthesis of purine nucleoside analogues using copper-mediated C(sp2)–H activation.
Scheme 77: (A) Copper-mediated annulation of acrylamide; (B) achieved scope, including the synthesis of the co...
Scheme 78: (A) Known bioactive compounds containing a naphthyl aryl ether motif; (B and C) copper-mediated eth...
Scheme 79: (A and B) Cu-mediated alkylation of N-oxide-heteroarenes; (C) late-stage modification.
Scheme 80: (A) Cu-mediated cross-dehydrogenative coupling of polyfluoroarenes and alkanes; (B) scope from know...
Scheme 81: (A) Known anticancer acrylonitrile compounds; (B and C) Copper-mediated cyanation of unactivated al...
Scheme 82: (A) Cu-mediated radiofluorination of 8-aminoquinoline-derived aryl amides; (B) achieved scope, incl...
Scheme 83: (A) Examples of natural β-carbolines; (B and C) an example of a zinc-catalyzed C–H functionalizatio...
Scheme 84: (A) Examples of anticancer α-aminophosphonic acid derivatives; (B and C) an example of a zinc-catal...
Beilstein J. Org. Chem. 2021, 17, 1490–1498, doi:10.3762/bjoc.17.105
Graphical Abstract
Scheme 1: Retrosynthetic analysis of heterocycles A and B.
Figure 1: Molecular structure of compound 3a, displacement parameters are drawn at 50%.
Scheme 2: Free-radical cyclization of N-protected and N-unprotected pyrroles 1a and 2.
Scheme 3: Synthesis of 2H-pyrido[2,1-a]pyrrolo[3,4-c]isoquinolin-4-ium bromide 8.
Scheme 4: Free-radical cyclization of dihalogeno-substituted salts 9 and 12.
Figure 2: Molecular structure of compound 13, displacement parameters are drawn at 50% probability level.
Scheme 5: N-alkylation of the base 6a.
Figure 3: Molecular structure of compound 17a, displacement parameters are drawn at 50% probability level.
Scheme 6: Isomerization of compounds 17a and 18a.
Scheme 7: N-Alkylation of compounds 18a and 19.
Beilstein J. Org. Chem. 2021, 17, 485–493, doi:10.3762/bjoc.17.42
Graphical Abstract
Figure 1: Bioactive molecules containing the 2-aminoquinoline motif.
Scheme 1: C2-selective C–N bond formation of N-oxides.
Scheme 2: Substrate scope of N-sulfonyl-1,2,3-triazoles. Reaction conditions: 1a (0.2 mmol), 2 (0.24 mmol) an...
Scheme 3: Substrate scope of quinoline N-oxides. Reaction conditions: 1 (0.2 mmol), 2a (0.24 mmol) and DCE (2...
Scheme 4: Late-stage modification of natural products.
Scheme 5: Substrate scope for the reaction of substituted triazoles with isoquinoline N-oxide.
Scheme 6: Gram-scale and one-pot synthesis.
Scheme 7: Proposed mechanism.
Beilstein J. Org. Chem. 2020, 16, 2363–2441, doi:10.3762/bjoc.16.197
Graphical Abstract
Scheme 1: Amine/photoredox-catalysed α-alkylation of aldehydes with alkyl bromides bearing electron-withdrawi...
Scheme 2: Amine/HAT/photoredox-catalysed α-functionalisation of aldehydes using alkenes.
Scheme 3: Amine/cobalt/photoredox-catalysed α-functionalisation of ketones and THIQs.
Scheme 4: Amine/photoredox-catalysed α-functionalisation of aldehydes or ketones with imines. (a) Using keton...
Scheme 5: Bifunctional amine/photoredox-catalysed enantioselective α-functionalisation of aldehydes.
Scheme 6: Bifunctional amine/photoredox-catalysed α-functionalisation of aldehydes using amine catalysts via ...
Scheme 7: Amine/photoredox-catalysed RCA of iminium ion intermediates. (a) Synthesis of quaternary stereocent...
Scheme 8: Bifunctional amine/photoredox-catalysed RCA of enones in a radical chain reaction initiated by an i...
Scheme 9: Bifunctional amine/photoredox-catalysed RCA reactions of iminium ions with different radical precur...
Scheme 10: Bifunctional amine/photoredox-catalysed radical cascade reactions between enones and alkenes with a...
Scheme 11: Amine/photocatalysed photocycloadditions of iminium ion intermediates. (a) External photocatalyst u...
Scheme 12: Amine/photoredox-catalysed addition of acrolein (94) to iminium ions.
Scheme 13: Dual NHC/photoredox-catalysed acylation of THIQs.
Scheme 14: NHC/photocatalysed spirocyclisation via photoisomerisation of an extended Breslow intermediate.
Scheme 15: CPA/photoredox-catalysed aza-pinacol cyclisation.
Scheme 16: CPA/photoredox-catalysed Minisci-type reaction between azaarenes and α-amino radicals.
Scheme 17: CPA/photoredox-catalysed radical additions to azaarenes. (a) α-Amino radical or ketyl radical addit...
Scheme 18: CPA/photoredox-catalysed reduction of azaarene-derived substrates. (a) Reduction of ketones. (b) Ex...
Scheme 19: CPA/photoredox-catalysed radical coupling reactions of α-amino radicals with α-carbonyl radicals. (...
Scheme 20: CPA/photoredox-catalysed Povarov reaction.
Scheme 21: CPA/photoredox-catalysed reactions with imines. (a) Decarboxylative imine generation followed by Po...
Scheme 22: Bifunctional CPA/photocatalysed [2 + 2] photocycloadditions.
Scheme 23: PTC/photocatalysed oxygenation of 1-indanone-derived β-keto esters.
Scheme 24: PTC/photoredox-catalysed perfluoroalkylation of 1-indanone-derived β-keto esters via a radical chai...
Scheme 25: Bifunctional hydrogen bonding/photocatalysed intramolecular [2 + 2] photocycloadditions of quinolon...
Scheme 26: Bifunctional hydrogen bonding/photocatalysed intramolecular RCA cyclisation of a quinolone.
Scheme 27: Bifunctional hydrogen bonding/photocatalysed intramolecular [2 + 2] photocycloadditions of quinolon...
Scheme 28: Bifunctional hydrogen bonding/photocatalysed [2 + 2] photocycloaddition reactions. (a) First use of...
Scheme 29: Bifunctional hydrogen bonding/photocatalysed deracemisation of allenes.
Scheme 30: Bifunctional hydrogen bonding/photocatalysed deracemisation reactions. (a) Deracemisation of sulfox...
Scheme 31: Bifunctional hydrogen bonding/photocatalysed intramolecular [2 + 2] photocycloaddition of coumarins....
Scheme 32: Bifunctional hydrogen bonding/photocatalysed [2 + 2] photocycloadditions of quinolones. (a) Intramo...
Scheme 33: Hydrogen bonding/photocatalysed formal arylation of benzofuranones.
Scheme 34: Hydrogen bonding/photoredox-catalysed dehalogenative protonation of α,α-chlorofluoro ketones.
Scheme 35: Hydrogen bonding/photoredox-catalysed reductions. (a) Reduction of 1,2-diketones. (b) Reduction of ...
Scheme 36: Hydrogen bonding/HAT/photocatalysed deracemisation of cyclic ureas.
Scheme 37: Hydrogen bonding/HAT/photoredox-catalysed synthesis of cyclic sulfonamides.
Scheme 38: Hydrogen bonding/photoredox-catalysed reaction between imines and indoles.
Scheme 39: Chiral cation/photoredox-catalysed radical coupling of two α-amino radicals.
Scheme 40: Chiral phosphate/photoredox-catalysed hydroetherfication of alkenols.
Scheme 41: Chiral phosphate/photoredox-catalysed synthesis of pyrroloindolines.
Scheme 42: Chiral anion/photoredox-catalysed radical cation Diels–Alder reaction.
Scheme 43: Lewis acid/photoredox-catalysed cycloadditions of carbonyls. (a) Formal [2 + 2] cycloaddition of en...
Scheme 44: Lewis acid/photoredox-catalysed RCA reaction using a scandium Lewis acid between α-amino radicals a...
Scheme 45: Lewis acid/photoredox-catalysed RCA reaction using a copper Lewis acid between α-amino radicals and...
Scheme 46: Lewis acid/photoredox-catalysed synthesis of 1,2-amino alcohols from aldehydes and nitrones using a...
Scheme 47: Lewis acid/photocatalysed [2 + 2] photocycloadditions of enones and alkenes.
Scheme 48: Meggers’s chiral-at-metal catalysts.
Scheme 49: Lewis acid/photoredox-catalysed α-functionalisation of ketones with alkyl bromides bearing electron...
Scheme 50: Bifunctional Lewis acid/photoredox-catalysed radical coupling reaction using α-chloroketones and α-...
Scheme 51: Lewis acid/photocatalysed RCA of enones. (a) Using aldehydes as acyl radical precursors. (b) Other ...
Scheme 52: Bifunctional Lewis acid/photocatalysis for a photocycloaddition of enones.
Scheme 53: Lewis acid/photoredox-catalysed RCA reactions of enones using DHPs as radical precursors.
Scheme 54: Lewis acid/photoredox-catalysed functionalisation of β-ketoesters. (a) Hydroxylation reaction catal...
Scheme 55: Bifunctional copper-photocatalysed alkylation of imines.
Scheme 56: Copper/photocatalysed alkylation of imines. (a) Bifunctional copper catalysis using α-silyl amines....
Scheme 57: Bifunctional Lewis acid/photocatalysed intramolecular [2 + 2] photocycloaddition.
Scheme 58: Bifunctional Lewis acid/photocatalysed [2 + 2] photocycloadditions (a) Intramolecular cycloaddition...
Scheme 59: Bifunctional Lewis acid/photocatalysed rearrangement of 2,4-dieneones.
Scheme 60: Lewis acid/photocatalysed [2 + 2] cycloadditions of cinnamate esters and styrenes.
Scheme 61: Nickel/photoredox-catalysed arylation of α-amino acids using aryl bromides.
Scheme 62: Nickel/photoredox catalysis. (a) Desymmetrisation of cyclic meso-anhydrides using benzyl trifluorob...
Scheme 63: Nickel/photoredox catalysis for the acyl-carbamoylation of alkenes with aldehydes using TBADT as a ...
Scheme 64: Bifunctional copper/photoredox-catalysed C–N coupling between α-chloro amides and carbazoles or ind...
Scheme 65: Bifunctional copper/photoredox-catalysed difunctionalisation of alkenes with alkynes and alkyl or a...
Scheme 66: Copper/photoredox-catalysed decarboxylative cyanation of benzyl phthalimide esters.
Scheme 67: Copper/photoredox-catalysed cyanation reactions using TMSCN. (a) Propargylic cyanation (b) Ring ope...
Scheme 68: Palladium/photoredox-catalysed allylic alkylation reactions. (a) Using alkyl DHPs as radical precur...
Scheme 69: Manganese/photoredox-catalysed epoxidation of terminal alkenes.
Scheme 70: Chromium/photoredox-catalysed allylation of aldehydes.
Scheme 71: Enzyme/photoredox-catalysed dehalogenation of halolactones.
Scheme 72: Enzyme/photoredox-catalysed dehalogenative cyclisation.
Scheme 73: Enzyme/photoredox-catalysed reduction of cyclic imines.
Scheme 74: Enzyme/photocatalysed enantioselective reduction of electron-deficient alkenes as mixtures of (E)/(Z...
Scheme 75: Enzyme/photoredox catalysis. (a) Deacetoxylation of cyclic ketones. (b) Reduction of heteroaromatic...
Scheme 76: Enzyme/photoredox-catalysed synthesis of indole-3-ones from 2-arylindoles.
Scheme 77: Enzyme/HAT/photoredox catalysis for the DKR of primary amines.
Scheme 78: Bifunctional enzyme/photoredox-catalysed benzylic C–H hydroxylation of trifluoromethylated arenes.
Beilstein J. Org. Chem. 2020, 16, 1357–1410, doi:10.3762/bjoc.16.116
Graphical Abstract
Figure 1: Examples of biologically active thietane-containing molecules.
Figure 2: The diverse methods for the synthesis of thietanes.
Scheme 1: Synthesis of 1-(thietan-2-yl)ethan-1-ol (10) from 3,5-dichloropentan-2-ol (9).
Scheme 2: Synthesis of thietanose nucleosides 2,14 from 2,2-bis(bromomethyl)propane-1,3-diol (11).
Scheme 3: Synthesis of methyl 3-vinylthietane-3-carboxylate (19).
Scheme 4: Synthesis of 1,6-thiazaspiro[3.3]heptane (24).
Scheme 5: Synthesis of 6-amino-2-thiaspiro[3.3]heptane hydrochloride (28).
Scheme 6: Synthesis of optically active thietane 31 from vitamin C.
Scheme 7: Synthesis of an optically active thietane nucleoside from diethyl L-tartrate (32).
Scheme 8: Synthesis of thietane-containing spironucleoside 40 from 5-aldo-3-O-benzyl-1,2-O-isopropylidene-α-D...
Scheme 9: Synthesis of optically active 2-methylthietane-containing spironucleoside 43.
Scheme 10: Synthesis of a double-linked thietane-containing spironucleoside 48.
Scheme 11: Synthesis of two diastereomeric thietanose nucleosides via 2,4-di(benzyloxymethyl)thietane (49).
Scheme 12: Synthesis of the thietane-containing PI3k inhibitor candidate 54.
Scheme 13: Synthesis of the spirothietane 57 as the key intermediate to Nuphar sesquiterpene thioalkaloids.
Scheme 14: Synthesis of spirothietane 61 through a direct cyclic thioetherification of 3-mercaptopropan-1-ol.
Scheme 15: Synthesis of thietanes 66 from 1,3-diols 62.
Scheme 16: Synthesis of thietanylbenzimidazolone 75 from (iodomethyl)thiazolobenzimidazole 70.
Scheme 17: Synthesis of 2-oxa-6-thiaspiro[3.3]heptane (80) from bis(chloromethyl)oxetane 76 and thiourea.
Scheme 18: Synthesis of the thietane-containing glycoside, 2-O-p-toluenesulfonyl-4,6-thioanhydro-α-D-gulopyran...
Scheme 19: Synthesis of methyl 4,6-thioanhydro-α-D-glucopyranoside (89).
Scheme 20: Synthesis of thietane-fused α-D-galactopyranoside 93.
Scheme 21: Synthesis of thietane-fused α-D-gulopyranoside 100.
Scheme 22: Synthesis of 3,5-anhydro-3-thiopentofuranosides 104.
Scheme 23: Synthesis of anhydro-thiohexofuranosides 110, 112 and 113 from from 1,2:4,5-di-O-isopropylidene D-f...
Scheme 24: Synthesis of optically active thietanose nucleosides from D- and L-xyloses.
Scheme 25: Synthesis of thietane-fused nucleosides.
Scheme 26: Synthesis of 3,5-anhydro-3-thiopentofuranosides.
Scheme 27: Synthesis of 2-amino-3,5-anhydro-3-thiofuranoside 141.
Scheme 28: Synthesis of thietane-3-ols 145 from (1-chloromethyl)oxiranes 142 and hydrogen sulfide.
Scheme 29: Synthesis of thietane-3-ol 145a from chloromethyloxirane (142a).
Scheme 30: Synthesis of thietane-3-ols 145 from 2-(1-haloalkyl)oxiranes 142 and 147 with ammonium monothiocarb...
Scheme 31: Synthesis of 7-deoxy-5(20)thiapaclitaxel 154a, a thietane derivative of taxoids.
Scheme 32: Synthesis of 5(20)-thiadocetaxel 158 from 10-deacetylbaccatin III (155).
Scheme 33: Synthesis of thietane derivatives 162 as precursors for deoxythiataxoid synthesis through oxiraneme...
Scheme 34: Synthesis of 7-deoxy 5(20)-thiadocetaxel 154b.
Scheme 35: Mechanism for the formation of the thietane ring in 171 from oxiranes with vicinal leaving groups 1...
Scheme 36: Synthesis of cis-2,3-disubstituted thietane 175 from thiirane-2-methanol 172.
Scheme 37: Synthesis of a bridged thietane 183 from aziridine cyclohexyl tosylate 179 and ammonium tetrathiomo...
Scheme 38: Synthesis of thietanes via the photochemical [2 + 2] cycloaddition of thiobenzophenone 184a with va...
Scheme 39: Synthesis of spirothietanes through the photo [2 + 2] cycloaddition of cyclic thiocarbonyls with ol...
Scheme 40: Photochemical synthesis of spirothietane-thioxanthenes 210 from thioxanthenethione (208) and butatr...
Scheme 41: Synthesis of thietanes 213 from 2,4,6-tri(tert-butyl)thiobenzaldehyde (211) with substituted allene...
Scheme 42: Photochemical synthesis of spirothietanes 216 and 217 from N-methylthiophthalimide (214) with olefi...
Scheme 43: Synthesis of fused thietanes from quadricyclane with thiocarbonyl derivatives 219.
Scheme 44: Synthesis of tricyclic thietanes via the photo [2 + 2] cycloaddition of N-methyldithiosuccinimides ...
Scheme 45: Synthesis of tricyclic thietanes via the photo [2 + 2] cycloaddition of N-methylthiosuccinimide/thi...
Scheme 46: Synthesis of tricyclic thietanes via the photo [2 + 2] cycloaddition of N-alkylmonothiophthalimides...
Scheme 47: Synthesis of spirothietanes from dithiosuccinimides 223 with 2,3-dimethyl-2-butene (215a).
Scheme 48: Synthesis of thietanes 248a,b from diaryl thione 184b and ketene acetals 247a,b.
Scheme 49: Photocycloadditions of acridine-9-thiones 249 and pyridine-4(1H)-thione (250) with 2-methylacrynitr...
Scheme 50: Synthesis of thietanes via the photo [2 + 2] cycloaddition of mono-, di-, and trithiobarbiturates 2...
Scheme 51: Synthesis of spirothietanes via the photo [2 + 2] cycloaddition of 1,1,3-trimethyl-2-thioxo-1,2-dih...
Scheme 52: Synthesis of spirothietanes via the photo [2 + 2] cycloaddition of thiocoumarin 286 with olefins.
Scheme 53: Photochemical synthesis of thietanes 296–299 from semicyclic and acyclic thioimides 292–295 and 2,3...
Scheme 54: Photochemical synthesis of spirothietane 301 from 1,3,3-trimethylindoline-2-thione (300) and isobut...
Scheme 55: Synthesis of spirobenzoxazolethietanes 303 via the photo [2 + 2] cycloaddition of alkyl and aryl 2-...
Scheme 56: Synthesis of spirothietanes from tetrahydrothioxoisoquinolines 306 and 307 with olefins.
Scheme 57: Synthesis of spirothietanes from 1,3-dihydroisobenzofuran-1-thiones 311 and benzothiophene-1-thione...
Scheme 58: Synthesis of 2-triphenylsilylthietanes from phenyl triphenylsilyl thioketone (316) with electron-po...
Scheme 59: Diastereoselective synthesis of spiropyrrolidinonethietanes 320 via the photo [2 + 2] cycloaddition...
Scheme 60: Synthesis of bicyclic thietane 323 via the photo [2 + 2] cycloaddition of 2,4-dioxo-3,4-dihydropyri...
Scheme 61: Photo-induced synthesis of fused thietane-2-thiones 325 and 326 from silacyclopentadiene 324 and ca...
Scheme 62: Synthesis of highly strained tricyclic thietanes 328 via the intramolecular photo [2 + 2] cycloaddi...
Scheme 63: Synthesis of tri- and pentacyclic thietanes 330 and 332, respectively, through the intramolecular p...
Scheme 64: Synthesis of tricyclic thietanes 334 via the intramolecular photo [2 + 2] cycloaddition of N-vinylt...
Scheme 65: Synthesis of tricyclic thietanes 336 via the intramolecular photo [2 + 2] cycloaddition of N-but-3-...
Scheme 66: Synthesis of tricyclic thietanes via the intramolecular photo [2 + 2] cycloaddition of N-but-3-enyl...
Scheme 67: Synthesis of tetracyclic thietane 344 through the intramolecular photo [2 + 2] cycloaddition of N-[...
Scheme 68: Synthesis of tri- and tetracyclic thietanes 348, 350, and 351, through the intramolecular photo [2 ...
Scheme 69: Synthesis of tetracyclic fused thietane 354 via the photo [2 + 2] cycloaddition of vinyl 2-thioxo-3H...
Scheme 70: Synthesis of highly rigid thietane-fused β-lactams via the intramolecular photo [2 + 2] cycloadditi...
Scheme 71: Asymmetric synthesis of a highly rigid thietane-fused β-lactam 356a via the intramolecular photo [2...
Scheme 72: Diastereoselective synthesis of the thietane-fused β-lactams via the intramolecular photo [2 + 2] c...
Scheme 73: Asymmetric synthesis of thietane-fused β-lactams 356 via the intramolecular photo [2 + 2] cycloaddi...
Scheme 74: Synthesis of the bridged bis(trifluoromethyl)thietane from 2,2,4,4-tetrakis(trifluoromethyl)-1,3-di...
Scheme 75: Synthesis of the bridged-difluorothietane 368 from 2,2,4,4-tetrafluoro-1,3-dithietane (367) and qua...
Scheme 76: Synthesis of bis(trifluoromethyl)thietanes from 2,2,4,4-tetrakis(trifluoromethyl)-1,3-dithietane (3...
Scheme 77: Synthesis of 2,2-dimethylthio-4,4-di(trifluoromethyl)thietane (378) from 2,2,4,4-tetrakis(trifluoro...
Scheme 78: Formation of bis(trifluoromethyl)thioacetone (381) through nucleophilic attack of dithietane 363 by...
Scheme 79: Synthesis of 2,2-bis(trifluoromethyl)thietanes from 2,2,4,4-tetrakis(trifluoromethyl)-1,3-dithietan...
Scheme 80: Synthesis of the bridged bis(trifluoromethyl)thietane 364 from of 2,2,4,4-tetrakis(trifluoromethyl)...
Scheme 81: Synthesis of 2,4-diiminothietanes 390 from alkenimines and 4-methylbenzenesulfonyl isothiocyanate (...
Scheme 82: Synthesis of arylidene 2,4-diiminothietanes 393 starting from phosphonium ylides 391 and isothiocya...
Scheme 83: Synthesis of thietane-2-ylideneacetates 397 through a DABCO-catalyzed formal [2 + 2] cycloaddition ...
Scheme 84: Synthesis of 3-substituted thietanes 400 from (1-chloroalkyl)thiiranes 398.
Scheme 85: Synthesis of N-(thietane-3-yl)azaheterocycles 403 and 404 through reaction of chloromethylthiirane (...
Scheme 86: Synthesis of 3-sulfonamidothietanes 406 from sulfonamides and chloromethylthiirane (398a).
Scheme 87: Synthesis of N-(thietane-3-yl)isatins 408 from chloromethylthiirane (398a) and isatins 407.
Scheme 88: Synthesis of 3-(nitrophenyloxy)thietanes 410 from nitrophenols 409 and chloromethylthiirane (398a).
Scheme 89: Synthesis of N-aryl-N-(thietane-3-yl)cyanamides 412 from N-arylcyanamides 411 and chloromethylthiir...
Scheme 90: Synthesis of 1-(thietane-3-yl)pyrimidin-2,4(1H,3H)-diones 414 from chloromethylthiirane (398a) and ...
Scheme 91: Synthesis of 2,4-diiminothietanes 418 from 2-iminothiiranes 416 and isocyanoalkanes 415.
Scheme 92: Synthesis of 2-vinylthietanes 421 from thiiranes 419 and 3-chloroallyl lithium (420).
Scheme 93: Synthesis of thietanes from thiiranes 419 and trimethyloxosulfonium iodide 424.
Scheme 94: Mechanism for synthesis of thietanes 425 from thiiranes 419 and trimethyloxosulfonium iodide 424.
Scheme 95: Synthesis of functionalized thietanes from thiiranes and dimethylsulfonium acylmethylides.
Scheme 96: Mechanism for the rhodium-catalyzed synthesis of functionalized thietanes 429 from thiiranes 419 an...
Scheme 97: Synthesis of 3-iminothietanes 440 through thermal isomerization from 4,5-dihydro-1,3-oxazole-4-spir...
Scheme 98: Synthesis of thietanes 443 from 3-chloro-2-methylthiolane (441) through ring contraction.
Scheme 99: Synthesis of an optically active thietanose 447 from D-xylose involving a ring contraction.
Scheme 100: Synthesis of optically thietane 447 via the DAST-mediated ring contraction of 448.
Scheme 101: Synthesis of the optically thietane nucleoside 451 via the ring contraction of thiopentose in 450.
Scheme 102: Synthesis of spirothietane 456 from 3,3,5,5-tetramethylthiolane-2,4-dithione (452) and benzyne (453...
Scheme 103: Synthesis of thietanes 461 via photoisomerization of 2H,6H-thiin-3-ones 459.
Scheme 104: Phosphorodithioate-mediated synthesis of 1,4-diarylthietanes 465.
Scheme 105: Mechanism of the phosphorodithioate-mediated synthesis of 1,4-diarylthietanes 465.
Scheme 106: Phosphorodithioate-mediated synthesis of trisubstituted thietanes (±)-470.
Scheme 107: Mechanism on the phosphorodithioate-mediated synthesis of trisubstituted thietanes.
Scheme 108: Phosphorodithioate-mediated synthesis of thietanes (±)-475.
Scheme 109: Phosphorodithioate-mediated synthesis of 1,2-disubstituted thietanes from aldehydes 476 and acrylon...
Scheme 110: Phosphorodithioate-mediated synthesis of 1,2-disubstituted thietanes via a one-pot three-component ...
Scheme 111: Mechanism for the phosphorodithioate-mediated synthesis of 1,2-disubstituted thietanes via three-co...
Scheme 112: Phosphorodithioate-mediated synthesis of substituted 3-nitrothietanes.
Scheme 113: Mechanism on the phosphorodithioate-mediated synthesis of 1,2-disubstituted thietanes (±)-486.
Scheme 114: Asymmetric synthesis of (S)-2-phenylthietane (497).
Scheme 115: Asymmetric synthesis of optically active 2,4-diarylthietanes.
Scheme 116: Synthesis of 3-acetamidothietan-2-one 503 via the intramolecular thioesterification of 3-mercaptoal...
Scheme 117: Synthesis of 4-substituted thietan-2-one via the intramolecular thioesterification of 3-mercaptoalk...
Scheme 118: Synthesis of 4,4-disubstituted thietan-2-one 511 via the intramolecular thioesterification of the 3...
Scheme 119: Synthesis of a spirothietan-2-one 514 via the intramolecular thioesterification of 3-mercaptoalkano...
Scheme 120: Synthesis of thiatetrahydrolipstatin starting from (S)-(−)-epichlorohydrin ((S)-142a).
Scheme 121: Synthesis of 2-phenethyl-4-(propan-2-ylidene)thietane (520) from 5-bromo-6-methyl-1-phenylhept-5-en...
Scheme 122: Synthesis of 2-phenethyl-4-(propan-2-ylidene)thietane (520) directly from S-(5-bromo-6-methyl-1-phe...
Scheme 123: Synthesis of 2-alkylidenethietanes from S-(2-bromoalk-1-en-4-yl)thioacetates.
Scheme 124: Synthesis of 2-alkylidenethietanes from S-(2-bromo/chloroalk-1-en-4-yl)thiols.
Scheme 125: Synthesis of spirothietan-3-ol 548 from enone 545 and ammonium hydrosulfide.
Scheme 126: Asymmetric synthesis of the optically active thietanoside from cis-but-2-ene-1,4-diol (47).
Scheme 127: Synthesis of 2-alkylidenethietan-3-ols 557 via the fluoride-mediated cyclization of thioacylsilanes ...
Scheme 128: Synthesis of 2-iminothietanes via the reaction of propargylbenzene (558) and isothiocyanates 560 in...
Scheme 129: Synthesis of 2-benzylidenethietane 567 via the nickel complex-catalyzed electroreductive cyclizatio...
Scheme 130: Synthesis of 2-iminothietanes 569 via the photo-assisted electrocyclic reaction of N-monosubstitute...
Scheme 131: Synthesis of ethyl 3,4-diiminothietane-2-carboxylates from ethyl thioglycolate (570) and bis(imidoy...
Scheme 132: Synthesis of N-(thietan-3-yl)-α-oxoazaheterocycles from azaheterocyclethiones and chloromethyloxira...
Scheme 133: Synthesis of thietan-3-yl benzoate (590) via the nickel-catalyzed intramolecular reductive thiolati...
Scheme 134: Synthesis of 2,2-bis(trifluoromethyl)thietane from 3,3-bis(trifluoromethyl)-1,2-dithiolane.
Scheme 135: Synthesis of thietanes from enamines and sulfonyl chlorides.
Scheme 136: Synthesis of spirothietane 603 via the [2 + 3] cycloaddition of 2,2,4,4-tetramethylcyclobutane-1,3-...
Scheme 137: Synthesis of thietane (605) from 1-bromo-3-chloropropane and sulfur.
Beilstein J. Org. Chem. 2020, 16, 1234–1276, doi:10.3762/bjoc.16.107
Graphical Abstract
Figure 1: Imine-N-oxyl radicals (IV) discussed in the present review and other classes of N-oxyl radicals (I–...
Figure 2: The products of decomposition of iminoxyl radicals generated from oximes by oxidation with Ag2O.
Scheme 1: Generation of oxime radicals and study of the kinetics of their decay by photolysis of the solution...
Scheme 2: Synthesis of di-tert-butyliminoxyl radical and its decomposition products.
Scheme 3: The proposed reaction pathway of the decomposition of di-tert-butyliminoxyl radical (experimentally...
Scheme 4: Monomolecular decomposition of the tert-butyl(triethylmethyl)oxime radical.
Scheme 5: The synthesis and stability of the most stable dialkyl oxime radicals – di-tert-butyliminoxyl and d...
Scheme 6: The formation of iminoxyl radicals from β-diketones under the action of NO2.
Scheme 7: Synthesis of the diacetyliminoxyl radical.
Scheme 8: Examples of long-living oxime radicals with electron-withdrawing groups and the conditions for thei...
Figure 3: The electronic structure iminoxyl radicals and their geometry compared to the corresponding oximes.
Figure 4: Bond dissociation enthalpies (kcal/mol) of oximes and N,N-disubstituted hydroxylamines calculated o...
Scheme 9: Examples demonstrating the low reactivity of the di-tert-butyliminoxyl radical towards the substrat...
Scheme 10: The reactions of di-tert-butyliminoxyl radical with unsaturated hydrocarbons involving hydrogen ato...
Scheme 11: Possible mechanisms of reaction of di-tert-butyliminoxyl radical with alkenes.
Scheme 12: Products of the reaction between di-tert-butyliminoxyl radical and phenol derivatives.
Scheme 13: The reaction of di-tert-butyliminoxyl radical with amines.
Scheme 14: Reaction of di-tert-butyliminoxyl radicals with organolithium reagents.
Scheme 15: Cross-dehydrogenative C–O coupling of 1,3-dicarbonyl compounds with oximes under the action of mang...
Scheme 16: Cross-dehydrogenative C–O coupling of 1,3-dicarbonyl compounds with oximes under the action of Cu(BF...
Scheme 17: Oxidative C–O coupling of benzylmalononitrile (47) with 3-(hydroxyimino)pentane-2,4-dione (19).
Scheme 18: The proposed mechanism of the oxidative coupling of benzylmalononitrile (47) with diacetyl oxime (19...
Scheme 19: Oxidative C–O coupling of pyrazolones with oximes under the action of Fe(ClO4)3.
Scheme 20: The reaction of diacetyliminoxyl radical with pyrazolones.
Scheme 21: Oxidative C–O coupling of oximes with acetonitrile, ketones, and esters.
Scheme 22: Intramolecular cyclizations of oxime radicals to form substituted isoxazolines or cyclic nitrones.
Scheme 23: TEMPO-mediated oxidative cyclization of oximes with C–H bond cleavage.
Scheme 24: Proposed reaction mechanism of oxidative cyclization of oximes with C–H bond cleavage.
Scheme 25: Selectfluor/Bu4NI-mediated C–H oxidative cyclization of oximes.
Scheme 26: Oxidative cyclization of N-benzyl amidoximes to 1,2,4-oxadiazoles.
Scheme 27: The formation of quinazolinone 73a from 5-phenyl-4,5-dihydro-1,2,4-oxadiazole 74 under air.
Scheme 28: DDQ-mediated oxidative cyclization of thiohydroximic acids.
Scheme 29: Plausible mechanism of the oxidative cyclization of thiohydroximic acids.
Scheme 30: Silver-mediated oxidative cyclization of α-halogenated ketoximes and 1,3-dicarbonyl compounds.
Scheme 31: Possible pathway of one-pot oxidative cyclization of α-halogenated ketoximes and 1,3-dicarbonyl com...
Scheme 32: T(p-F)PPT-catalyzed oxidative cyclization of oximes with the formation of 1,2,4-oxadiazolines.
Scheme 33: Intramolecular cyclization of iminoxyl radicals involving multiple C=C and N=N bonds.
Scheme 34: Oxidative cyclization of β,γ- and γ,δ-unsaturated oximes employing the DEAD or TEMPO/DEAD system wi...
Scheme 35: Cobalt-catalyzed aerobic oxidative cyclization of β,γ-unsaturated oximes.
Scheme 36: Manganese-catalyzed aerobic oxidative cyclization of β,γ-unsaturated oximes.
Scheme 37: Visible light photocatalytic oxidative cyclization of β,γ-unsaturated oximes.
Scheme 38: TBAI/TBHP-mediated radical cascade cyclization of the β,γ-unsaturated oximes.
Scheme 39: TBAI/TBHP-mediated radical cascade cyclization of vinyl isocyanides with β,γ-unsaturated oximes.
Scheme 40: tert-Butylnitrite-mediated oxidative cyclization of unsaturated oximes with the introduction of an ...
Scheme 41: Transformation of unsaturated oxime to oxyiminomethylisoxazoline via the confirmed dimeric nitroso ...
Scheme 42: tert-Butylnitrite-mediated oxidative cyclization of unsaturated oximes with the introduction of a n...
Scheme 43: Synthesis of cyano-substituted oxazolines from unsaturated oximes using the TBN/[RuCl2(p-cymene)]2 ...
Scheme 44: Synthesis of trifluoromethylthiolated isoxazolines from unsaturated oximes.
Scheme 45: Copper-сatalyzed oxidative cyclization of β,γ-unsaturated oximes with the introduction of an azido ...
Scheme 46: TBHP-mediated oxidative cascade cyclization of β,γ-unsaturated oximes and unsaturated N-arylamides.
Scheme 47: Copper-сatalyzed oxidative cyclization of unsaturated oximes with the introduction of an amino grou...
Scheme 48: TEMPO-mediated oxidative cyclization of unsaturated oximes followed by elimination.
Scheme 49: Oxidative cyclization of β,γ-unsaturated oximes with the introduction of a trifluoromethyl group.
Scheme 50: Oxidative cyclization of unsaturated oximes with the introduction of a nitrile group.
Scheme 51: Oxidative cyclization of β,γ-unsaturated oximes to isoxazolines with the introduction of a nitrile ...
Scheme 52: Oxidative cyclization of β,γ-unsaturated oximes to isoxazolines with the introduction of a sulfonyl...
Scheme 53: Oxidative cyclization of β,γ- and γ,δ-unsaturated oximes to isoxazolines with the introduction of a...
Scheme 54: Oxidative cyclization of β,γ-unsaturated oximes to isoxazolines with the introduction of a thiocyan...
Scheme 55: PhI(OAc)2-mediated oxidative cyclization of oximes with C–S and C–Se bond formation.
Scheme 56: PhI(OAc)2-mediated oxidative cyclization of unsaturated oximes accompanied by alkoxylation.
Scheme 57: PhI(OAc)2-mediated cyclization of unsaturated oximes to methylisoxazolines.
Scheme 58: Oxidative cyclization-alkynylation of unsaturated oximes.
Scheme 59: TEMPO-mediated oxidative cyclization of C-glycoside ketoximes to C-glycosylmethylisoxazoles.
Scheme 60: Silver-сatalyzed oxidative cyclization of β,γ-unsaturated oximes with formation of fluoroalkyl isox...
Scheme 61: Oxidative cyclization of β,γ-unsaturated oximes with the formation of haloalkyl isoxazolines.
Scheme 62: Cyclization of β,γ-unsaturated oximes into haloalkyl isoxazolines under the action of the halogenat...
Scheme 63: Synthesis of haloalkyl isoxazoles and cyclic nitrones via oxidative cyclization and 1,2-halogen shi...
Scheme 64: Electrochemical oxidative cyclization of diaryl oximes.
Scheme 65: Copper-сatalyzed cyclization and dioxygenation oximes containing a triple C≡C bond.
Scheme 66: Photoredox-catalyzed sulfonylation of β,γ-unsaturated oximes by sulfonyl hydrazides.
Scheme 67: Oxidative cyclization of β,γ-unsaturated oximes with introduction of sulfonate group.
Scheme 68: Ultrasound-promoted oxidative cyclization of β,γ-unsaturated oximes.
Beilstein J. Org. Chem. 2020, 16, 1225–1233, doi:10.3762/bjoc.16.106
Graphical Abstract
Figure 1: Bioactive pyrrolo[2,1-a]isoquinolines and hexahydropyrrolo[2,1-a]isoquinolines.
Scheme 1: [3 + 2] Cycloaddition with amino esters or amino acids.
Scheme 2: Scaffolds derived from the initial [3 + 2] adducts.
Scheme 3: [3 + 2] Cycloaddition with amino esters or amino acids. Conditions: 1:3:4 (1.2:1:1.1), Et3N (1.5 eq...
Scheme 4: Synthesis of pyrrolo[2,1-a]isoquinolines 9. Reaction conditions: 5 (0.5 mmol, 1 equiv), 7 (3 equiv)...
Scheme 5: Synthesis of pyrrolo[2,1-a]isoquinolines 11. Reaction conditions: 6 (0.5 mmol, 1 equiv), 7 (3 equiv...
Scheme 6: Synthesis of pyrrolo[2,1-a]isoquinolines 12. Reaction conditions: 5 or 6 (0.5 mmol, 1 equiv), cinna...
Scheme 7: Plausible mechanism for the synthesis of 9a.
Beilstein J. Org. Chem. 2020, 16, 809–817, doi:10.3762/bjoc.16.74
Graphical Abstract
Scheme 1: Examples of photocatalytic C–C bond formation by nucleophilic trapping of a reactive THIQ intermedi...
Figure 1: Kinetic profile for the benzylation of 1 to 3.
Scheme 2: Benzylation of N-phenyl-THIQ.
Scheme 3: Benzylation of substituted N-arylTHIQs.
Scheme 4: Removal of the PMP protecting group.
Scheme 5: Alkylation of N-phenyl-THIQ derivatives. Conditions: a2 mol % [Ir(dtbbpy)(ppy)2]PF6, DMA, 60 h; b2 ...
Scheme 6: Proposed mechanism.
Beilstein J. Org. Chem. 2019, 15, 2304–2310, doi:10.3762/bjoc.15.222
Graphical Abstract
Figure 1: Marine pyridoacridine alkaloids amphimedine (1), ascididemin (2), kuanoniamine A (3), styelsamine D...
Figure 2: A–C): Published methods for the synthesis of 4,5-disubstituted benzo[c][2,7]naphthyridines; D) New ...
Scheme 1: Regioselective metalation of 4-bromobenzo[c][2,7]naphthyridine (9d) and subsequent conversion into ...
Scheme 2: Outcome of a D2O quenching experiment after metalation of 4-bromobenzo[c][2,7]naphthyridine (9d).
Scheme 3: Synthesis of 5-substituted 4-bromobenzo[c][2,7]naphthyridines via regioselective metalation of 9d u...
Scheme 4: Attempted synthesis of kuanoniamine A (3).
Scheme 5: Synthesis of pyrido[4,3,2-mn]acridone 22 starting from 20a via bromine–magnesium exchange reaction ...
Beilstein J. Org. Chem. 2019, 15, 1962–1973, doi:10.3762/bjoc.15.191
Graphical Abstract
Figure 1: Examples of some commercially available pharmaceuticals and agrochemicals containing the benzimidaz...
Figure 2: Formation of cationic species by protonation of 5-formyl-4-methylimidazole in TfOH and their reacti...
Figure 3: Benzimidazoles 1–8 used in this study.
Scheme 1: Reaction of 2-acetylbenzimidazole (2) with TfOH and benzene.
Scheme 2: Reactions of hydroxymethyl-substituted benzimidazole 7 and 8 with TfOH and benzene.
Scheme 3: Reaction mechanism of the formation of compounds 9–11.
Scheme 4: Reaction mechanism of the formation of compounds 12.
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, 1563–1568, doi:10.3762/bjoc.15.159
Graphical Abstract
Scheme 1: Synthetic approaches to [1,2,4]triazolo[4,3-a]pyridines.
Scheme 2: Synthesis of 3-methylphosphonylated [1,2,4]triazolo[4,3-a]pyridines. Reaction conditions: 1 (1 mmol...
Scheme 3: Synthesis of methylphosphonylated 6(8)-nitro-[1,2,4]triazolo[4,3-a]pyridines and 6(8)-nitro-[1,2,4]...
Scheme 4: Acid-promoted Dimroth rearrangement pathway.
Scheme 5: Synthesis of phosphonylated [1,2,4]triazolo[4,3-a]quinolines and [1,2,4]triazolo[3,4-a]isoquinoline...
Scheme 6: Plausible reaction pathway.
Beilstein J. Org. Chem. 2019, 15, 769–779, doi:10.3762/bjoc.15.73
Graphical Abstract
Figure 1: Commercially available ruthenium catalysts for metathesis reactions.
Figure 2: Retrosynthesis of the ruthenium catalysts.
Scheme 1: Efficient multigram synthesis of N,N-dialkyl-2-vinylbenzylamines 4 (R1X = Me2SO4, Et2SO4 or BnCl, s...
Scheme 2: Synthesis of N-(2-ethenylbenzyl)heterocycles 5.
Scheme 3: Synthesis of N-monoalkyl-2-vinylbenzylamine 7.
Scheme 4: Synthesis of Hoveyda–Grubbs-type catalysts 11.
Scheme 5: Synthesis of the “chloroform adduct” 9.
Figure 3: Selected X-ray data for ruthenium complexes 11a–c. All hydrogen atoms were deleted for clarity (exc...
Scheme 6: Catalytic activity of compounds 11 in the metathesis reactions.
Beilstein J. Org. Chem. 2018, 14, 891–899, doi:10.3762/bjoc.14.76
Graphical Abstract
Scheme 1: The Corey–Fuchs reaction.
Scheme 2: Electrochemical reduction of a carbon–halogen bond.
Scheme 3: Electrochemical synthesis of vinyl bromides [25].
Scheme 4: Scope of this work.
Figure 1: Voltammetric curves of 1a 0.020 mol dm−3; Pt, glassy carbon (GC) or Ag cathode. ν = 0.2 V s−1, T = ...
Scheme 5: Possible products from the electrolysis of 2-(2,2-dibromovinyl)naphthalene (1a).
Figure 2: Variation of the amounts of 1a, 2a, and 3a with the number of Faradays of 1a.
Scheme 6: Mechanistic hypothesis for the synthesis of alkyne 2a and bromoalkyne 3a from 2-(2,2-dibromovinyl)n...
Scheme 7: Possible reaction using NaClO4 as supporting electrolyte.
Scheme 8: Electrochemical synthesis of 9-ethyl-3-ethynyl-9H-carbazole (2b).
Scheme 9: Electrochemical synthesis of 1-ethynyl-4-methoxybenzene (2c).