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Search for "acetylenes" in Full Text gives 88 result(s) in Beilstein Journal of Organic Chemistry.
A systematic review on silica-, carbon-, and magnetic materials-supported copper species as efficient heterogeneous nanocatalysts in “click” reactions
- Pezhman Shiri and
- Jasem Aboonajmi
Beilstein J. Org. Chem. 2020, 16, 551–586, doi:10.3762/bjoc.16.52
- multitriazole products in polyethylene glycol as a green solvent at room temperature (Scheme 10). The authors proposed that sodium ʟ-ascorbate acted as a reducing agent in the reduction of Cu(II) to Cu(I). Aromatic/aliphatic terminal acetylenes and benzyl bromides bearing electron-rich and electron-deficient
Graphical Abstract
Scheme 1: Chemical structure of the catalysts 1a and 1b and their catalytic application in CuAAC reactions.
Scheme 2: Synthetic route to the catalyst 11 and its catalytic application in CuAAC reactions.
Scheme 3: Synthetic route of dendrons, illustrated using G2-AMP 23.
Scheme 4: The catalytic application of CuYAu–Gx-AAA–SBA-15 in a CuAAC reaction.
Scheme 5: Synthetic route to the catalyst 36.
Scheme 6: Application of the catalyst 36 in CuAAC reactions.
Scheme 7: The synthetic route to the catalyst 45 and catalytic application of 45 in “click” reactions.
Scheme 8: Synthetic route to the catalyst 48 and catalytic application of 48 in “click” reactions.
Scheme 9: Synthetic route to the catalyst 58 and catalytic application of 58 in “click” reactions.
Scheme 10: Synthetic route to the catalyst 64 and catalytic application of 64 in “click” reactions.
Scheme 11: Chemical structure of the catalyst 68 and catalytic application of 68 in “click” reactions.
Scheme 12: Chemical structure of the catalyst 69 and catalytic application of 69 in “click” reactions.
Scheme 13: Synthetic route to, and chemical structure of the catalyst 74.
Scheme 14: Application of the cayalyst 74 in “click” reactions.
Scheme 15: Synthetic route to, and chemical structure of the catalyst 78 and catalytic application of 78 in “c...
Scheme 16: Synthetic route to the catalyst 85.
Scheme 17: Application of the catalyst 85 in “click” reactions.
Scheme 18: Synthetic route to the catalyst 87 and catalytic application of 87 in “click” reactions.
Scheme 19: Chemical structure of the catalyst 88 and catalytic application of 88 in “click” reactions.
Scheme 20: Synthetic route to the catalyst 90 and catalytic application of 90 in “click” reactions.
Scheme 21: Synthetic route to the catalyst 96 and catalytic application of 96 in “click” reactions.
Scheme 22: Synthetic route to the catalyst 100 and catalytic application of 100 in “click” reactions.
Scheme 23: Synthetic route to the catalyst 102 and catalytic application of 23 in “click” reactions.
Scheme 24: Synthetic route to the catalysts 108–111.
Scheme 25: Catalytic application of 108–111 in “click” reactions.
Scheme 26: Synthetic route to the catalyst 121 and catalytic application of 121 in “click” reactions.
Scheme 27: Synthetic route to 125 and application of 125 in “click” reactions.
Scheme 28: Synthetic route to the catalyst 131 and catalytic application of 131 in “click” reactions.
Scheme 29: Synthetic route to the catalyst 136.
Scheme 30: Application of the catalyst 136 in “click” reactions.
Scheme 31: Synthetic route to the catalyst 141 and catalytic application of 141 in “click” reactions.
Scheme 32: Synthetic route to the catalyst 144 and catalytic application of 144 in “click” reactions.
Scheme 33: Synthetic route to the catalyst 149 and catalytic application of 149 in “click” reactions.
Scheme 34: Synthetic route to the catalyst 153 and catalytic application of 153 in “click” reactions.
Scheme 35: Synthetic route to the catalyst 155 and catalytic application of 155 in “click” reactions.
Scheme 36: Synthetic route to the catalyst 157 and catalytic application of 157 in “click” reactions.
Scheme 37: Synthetic route to the catalyst 162.
Scheme 38: Application of the catalyst 162 in “click” reactions.
Scheme 39: Synthetic route to the catalyst 167 and catalytic application of 167 in “click” reactions.
Scheme 40: Synthetic route to the catalyst 169 and catalytic application of 169 in “click” reactions.
Scheme 41: Synthetic route to the catalyst 172.
Scheme 42: Application of the catalyst 172 in “click” reactions.
Regio- and stereoselective synthesis of new ensembles of diversely functionalized 1,3-thiaselenol-2-ylmethyl selenides by a double rearrangement reaction
- Svetlana V. Amosova,
- Andrey A. Filippov,
- Nataliya A. Makhaeva,
- Alexander I. Albanov and
- Vladimir A. Potapov
Beilstein J. Org. Chem. 2020, 16, 515–523, doi:10.3762/bjoc.16.47
- reaction with activated acetylenes (Scheme 9). The reaction of the 1,3-thiaselenol-2-ylmethylselenolate anion with alkyl propiolates proceeded in a regio- and stereoselective manner affording alkyl 3-[(1,3-thiaselenol-2-ylmethyl)selanyl]-2-propenoates 7a (Z/E = 94:6) and 7b (Z/E = 93:7) in 94% and 90
- were developed. Selenocyanate 4 and diselenide 8 were shown to be the synthons of the 1,3-thiaselenol-2-ylmethylselenolate anion, which was involved in the nucleophilic substitution reactions and regio- and stereoselective nucleophilic additions to activated acetylenes. However, the method to generate
- organic halides, regio- and stereoselective nucleophilic addition to activated acetylenes and oxidation. Noteworthy, no other example for the synthesis of 1,3-thiaselenol-2-ylmethyl selenide derivatives was hitherto described. A high selectivity, mild reaction conditions and very simple work-up procedures
Graphical Abstract
Scheme 1: Possible formation of reaction products starting from 1 via seleniranium 2 or thiiranium cations 3.
Scheme 2: Unusual regio- and stereoselective nucleophilic reactions of thiaselenole 1 at two centers of the s...
Scheme 3: Reactions of thiaselenole 1 with С- and S-centered nucleophiles affording new families of linear un...
Scheme 4: The reactions of thiaselenole 1 with the formation of polyfunctionalized 2,3-dihydro-1,4-thiaseleni...
Scheme 5: The synthesis of new 1,3-thiaselenole ensembles by reactions of thiaselenole 1 with mercapto benzaz...
Scheme 6: The formation of product 4 via compound 5 by the reaction of thiaselenole 1 with potassium selenocy...
Figure 1: Monitoring the reaction of thiaselenole 1 with KSeCN by 1H NMR spectroscopy (in accordance with the...
Scheme 7: The reaction pathway for the formation of compounds 4 and 5.
Scheme 8: Synthesis of new ensembles of 1,3-thiaselenol-2-ylmethyl selenides 6a–l (77Se NMR data are included...
Scheme 9: The synthesis of vinyl selenides 7a,b through nucleophilic addition of 1,3-thiaselenol-2-ylmethylse...
Scheme 10: One-pot synthesis of diselenide 8 from thiaselenole 1 (77Se NMR data are included).
Scheme 11: Synthesis of compounds 6a–j from diselenide 8.
Palladium-catalyzed Sonogashira coupling reactions in γ-valerolactone-based ionic liquids
- László Orha,
- József M. Tukacs,
- László Kollár and
- László T. Mika
Beilstein J. Org. Chem. 2019, 15, 2907–2913, doi:10.3762/bjoc.15.284
- -ethoxyvalerate as a partially bio-based solvent can be utilized as alternative reaction medium for copper- and auxiliary base-free Pd-catalyzed Sonogashira coupling reactions of aryl iodides and functionalized acetylenes under mild conditions. Twenty-two cross-coupling products were isolated with good to
- been carried out in γ-valerolactone-originated ILs, which can act as solvent, ligand and base. Thus, the preparation of various acetylenes in a partially or even biomass-based solvent without any auxiliary material could further control and reduce the environmental impacts of this industrially
- important transformation. Herein we report a study on the palladium-catalyzed copper- and added base-free Sonogashira coupling reactions to synthesize various acetylenes in γ-valerolactone-based ionic liquids under mild conditions. Results and Discussion We recently demonstrated that copper-catalyzed
Graphical Abstract
Scheme 1: Palladium-catalyzed Sonogashira cross-coupling of iodobenzene (1a) and phenylacetylene (2a) in ioni...
Figure 1: Effect of catalyst precursors used in Sonogashira coupling reaction of iodobenzene (1a, 0.5 mmol) a...
Figure 2: Re-use of Pd catalyst for Sonogashira coupling of iodobenzene (1a) and phenylacetylene (2a). Reacti...
Recent advances in transition-metal-catalyzed incorporation of fluorine-containing groups
- Xiaowei Li,
- Xiaolin Shi,
- Xiangqian Li and
- Dayong Shi
Beilstein J. Org. Chem. 2019, 15, 2213–2270, doi:10.3762/bjoc.15.218
Graphical Abstract
Scheme 1: The main three strategies of fluorination: nucleophilic, electrophilic and radical fluorination.
Scheme 2: Doyle’s Pd-catalyzed fluorination of allylic chlorides.
Scheme 3: Allylic fluorination of 2- and 3-substituted propenyl esters.
Scheme 4: Regioselective allylic fluorination of cinnamyl phosphorothioate esters.
Scheme 5: Palladium-catalyzed aliphatic C–H fluorination reported by Doyle.
Scheme 6: Pd-catalyzed enantioselective fluorination of α-ketoesters followed by stereoselective reduction to...
Scheme 7: Pd-catalyzed C(sp3)–H fluorination of oxindoles.
Scheme 8: C–H fluorination of 8-methylquinoline derivatives with F− reagents.
Scheme 9: Fluorination of α-cyano acetates reported by van Leeuwen.
Scheme 10: The catalytic enantioselective electrophilic C–H fluorination of α-chloro-β-keto phosphonates.
Scheme 11: Fluorination of unactivated C(sp3)–H bonds directed by the bidentate PIP auxiliary.
Scheme 12: Fluorination of C(sp3)–H bonds at the β-position of carboxylic acids.
Scheme 13: Enantioselective benzylic C–H fluorination with a chiral transient directing group.
Scheme 14: Microwave-heated Pd-catalyzed fluorination of aryl alcohols.
Scheme 15: Fluorination of aryl potassium trifluoroborates.
Scheme 16: C(sp2)–F bond formation using precatalyst [L·Pd]2(cod).
Scheme 17: Pd-catalyzed fluorination of (hetero)aryl triflates and bromides.
Scheme 18: The Pd-catalyzed C–H fluorination of arenes with Selectfluor/NFSI.
Scheme 19: Pd(II)-catalyzed ortho-monofluorination protocol for benzoic acids.
Scheme 20: Pd-catalyzed C(sp2)–H bond fluorination of 2-arylbenzothiazoles.
Scheme 21: Nitrate-promoted fluorination of aromatic and olefinic C(sp2)–H bonds and proposed mechanism.
Scheme 22: Fluorination of oxalyl amide-protected benzylamine derivatives.
Scheme 23: C–H fluorination of benzaldehydes with orthanilic acids as transient directing group.
Scheme 24: Pd(II)-catalyzed aryl C–H fluorination with various directing groups.
Scheme 25: Cu-catalyzed aliphatic, allylic, and benzylic fluorination.
Scheme 26: Cu-catalyzed SN2 fluorination of primary and secondary alkyl bromides.
Scheme 27: Copper-catalyzed fluorination of alkyl triflates.
Scheme 28: Cu-catalyzed fluorination of allylic bromides and chlorides.
Scheme 29: Synthetic strategy for the fluorination of active methylene compounds.
Scheme 30: Fluorination of β-ketoesters using a tartrate-derived bidentate bisoxazoline-Cu(II) complex.
Scheme 31: Highly enantioselective fluorination of β-ketoesters and N-Boc-oxindoles.
Scheme 32: Amide group-assisted site-selective fluorination of α-bromocarbonyl compounds.
Scheme 33: Cu-mediated aryl fluorination reported by Sanford [77].
Scheme 34: Mono- or difluorination reactions of benzoic acid derivatives.
Scheme 35: Cu-catalyzed fluorination of diaryliodonium salts with KF.
Scheme 36: Copper(I)-catalyzed cross-coupling of 2-pyridylaryl bromides.
Scheme 37: AgNO3-catalyzed decarboxylative fluorination of aliphatic carboxylic acids.
Scheme 38: The Mn-catalyzed aliphatic and benzylic C–H fluorination.
Scheme 39: Iron(II)-promoted C–H fluorination of benzylic substrates.
Scheme 40: Ag-catalyzed fluorodecarboxylation of carboxylic acids.
Scheme 41: Vanadium-catalyzed C(sp3)–H fluorination.
Scheme 42: AgNO3-catalyzed radical deboronofluorination of alkylboronates and boronic acids.
Scheme 43: Selective heterobenzylic C–H fluorination with Selectfluor reported by Van Humbeck.
Scheme 44: Fe(II)-catalyzed site-selective fluorination guided by an alkoxyl radical.
Scheme 45: Fluorination of allylic trichloroacetimidates reported by Nguyen et al.
Scheme 46: Iridium-catalyzed fluorination of allylic carbonates with TBAF(t-BuOH)4.
Scheme 47: Iridium-catalyzed asymmetric fluorination of allylic trichloroacetimidates.
Scheme 48: Cobalt-catalyzed α-fluorination of β-ketoesters.
Scheme 49: Nickel-catalyzed α-fluorination of various α-chloro-β-ketoesters.
Scheme 50: Ni(II)-catalyzed enantioselective fluorination of oxindoles and β-ketoesters.
Scheme 51: Scandium(III)-catalyzed asymmetric C–H fluorination of unprotected 3-substituted oxindoles.
Scheme 52: Iron-catalyzed directed C–H fluorination.
Scheme 53: Electrophilic silver-catalyzed Ar–F bond-forming reaction from arylstannanes.
Figure 1: Nucleophilic, electrophilic and radical CF3 sources.
Scheme 54: Cu(I)-catalyzed allylic trifluoromethylation of unactivated terminal olefins.
Scheme 55: Direct copper-catalyzed trifluoromethylation of allylsilanes.
Scheme 56: Cupper-catalyzed enantioselective trifluoromethylation of five and six-membered ring β-ketoesters.
Scheme 57: Cu-catalyzed highly stereoselective trifluoromethylation of secondary propargyl sulfonates.
Scheme 58: Remote C(sp3)–H trifluoromethylation of carboxamides and sulfonamides.
Scheme 59: Trifluoromethylation of allylsilanes with photoredox catalysis.
Scheme 60: Ag-catalyzed decarboxylative trifluoromethylation of aliphatic carboxylic acids in aqueous CH3CN.
Scheme 61: Decarboxylative trifluoromethylation of aliphatic carboxylic acids via combined photoredox and copp...
Scheme 62: Palladium-catalyzed Ar–CF3 bond-forming reaction.
Scheme 63: Palladium-catalyzed trifluoromethylation of arenes with diverse heterocyclic directing groups.
Scheme 64: Pd-catalyzed trifluoromethylation of indoles as reported by Liu.
Scheme 65: Pd-catalyzed trifluoromethylation of vinyl triflates and vinyl nonaflates.
Scheme 66: Pd(II)-catalyzed ortho-trifluoromethylation of aromatic C–H bonds.
Scheme 67: Visible-light-induced Pd(OAc)2-catalyzed ortho-trifluoromethylation of acetanilides with CF3SO2Na.
Scheme 68: CuI-catalyzed trifluoromethylation of aryl- and alkenylboronic acids.
Scheme 69: Cu-catalyzed trifluoromethylation of aryl- and vinylboronic acids.
Scheme 70: Copper-catalyzed trifluoromethylation of α,β-unsaturated carboxylic acids.
Scheme 71: Formation of C(sp2)–CF3 bond catalyzed by copper(I) complex.
Scheme 72: Loh’s Cu(I)-catalyzed trifluoromethylation of enamides and electron-deficient alkenes.
Scheme 73: Copper and iron-catalyzed decarboxylative tri- and difluoromethylation.
Scheme 74: Cu-catalyzed trifluoromethylation of hydrazones developed by Bouyssi.
Scheme 75: Cu(I)-catalyzed trifluoromethylation of terminal alkenes.
Scheme 76: Cu/Ag-catalyzed decarboxylative trifluoromethylation of cinnamic acids.
Scheme 77: Copper-catalyzed direct alkenyl C–H trifluoromethylation.
Scheme 78: Copper(I/II)-catalyzed direct trifluoromethylation of styrene derivatives.
Scheme 79: Regioselective trifluoromethylation of pivalamido arenes and heteroarenes.
Scheme 80: Synthesis of trifluoromethylquinones in the presence of copper(I).
Scheme 81: Oxidative trifluoromethylation of imidazoheterocycles in ionic liquid/water.
Scheme 82: A mild and fast continuous-flow trifluoromethylation of coumarins using a CuI/CF3SO2Na/TBHP system.
Scheme 83: Copper-catalyzed oxidative trifluoromethylation of various 8-aminoquinolines.
Scheme 84: PA-directed copper-catalyzed trifluoromethylation of anilines.
Scheme 85: Trifluoromethylation of potassium vinyltrifluoroborates catalyzed by Fe(II).
Scheme 86: Alkenyl trifluoromethylation catalyzed by Ru(phen)3Cl2 as photocatalyst.
Scheme 87: Ru-catalyzed trifluoromethylation of alkenes by Akita’s group.
Scheme 88: Ir-catalyzed Cvinyl–CF3 bond formation of α,β-unsaturated carboxylic acids.
Scheme 89: Ag(I)-catalyzed denitrative trifluoromethylation of β-nitrostyrenes.
Scheme 90: Photocatalyzed direct trifluoromethylation of aryl and heteroaryl C–H bonds.
Scheme 91: Rhenium (MTO)-catalyzed direct trifluoromethylation of aromatic substrates.
Scheme 92: Trifluoromethylation of unprotected anilines under [Ir(ppy)3] catalyst.
Scheme 93: Oxidative trifluoromethylation of imidazopyridines and imidazoheterocycles.
Scheme 94: Ruthenium-catalyzed trifluoromethylation of (hetero)arenes with trifluoroacetic anhydride.
Scheme 95: Phosphovanadomolybdic acid-catalyzed direct C–H trifluoromethylation.
Scheme 96: Picolinamide-assisted ortho-trifluoromethylation of arylamines.
Scheme 97: A nickel-catalyzed C–H trifluoromethylation of free anilines.
Scheme 98: Cu-mediated trifluoromethylation of terminal alkynes reported by Qing.
Scheme 99: Huang’s C(sp)–H trifluoromethylation using Togni’s reagent.
Scheme 100: Cu-catalyzed methods for trifluoromethylation with Umemoto’s reagent.
Scheme 101: The synthesis of alkynyl-CF3 compounds in the presence of fac-[Ir(ppy)3] under visible-light irradi...
Scheme 102: Pd-catalyzed Heck reaction reported by Reutrakul.
Scheme 103: Difluoromethylation of enamides and ene-carbamates.
Scheme 104: Difluoromethylation of α,β-unsaturated carboxylic acids.
Scheme 105: Copper-catalyzed direct C(sp2)–H difluoroacetylation reported by Pannecoucke and co-workers.
Scheme 106: Difluoroalkylation of aldehyde-derived hydrazones with functionalized difluoromethyl bromides.
Scheme 107: Photoredox-catalyzed C–H difluoroalkylation of aldehyde-derived hydrazones.
Scheme 108: Synergistic ruthenium(II)-catalyzed C–H difluoromethylation reported by Ackermann.
Scheme 109: Visible-light photocatalytic decarboxylation of α,β-unsaturated carboxylic acids.
Scheme 110: Synthesis of difluorinated ketones via S-alkyl dithiocarbamates obtained from acyl chlorides and po...
Scheme 111: Synthesis of aryl and heteroaryl difluoromethylated phosphonates.
Scheme 112: Difluoroalkylation of secondary propargyl sulfonates using Cu as the catalyst.
Scheme 113: Ru(II)-mediated para-selective difluoromethylation of anilides and their derivatives.
Scheme 114: Bulky diamine ligand promoted cross-coupling of difluoroalkyl bromides.
Scheme 115: Copper-catalyzed C3–H difluoroacetylation of quinoxalinones.
Scheme 116: Copper(I) chloride-catalyzed trifluoromethylthiolation of enamines, indoles and β-ketoesters.
Scheme 117: Copper-boxmi-catalyzed asymmetric trifluoromethylthiolation of β-ketoesters.
Scheme 118: Direct Cu-catalyzed trifluoromethylthiolation of boronic acids and alkynes.
Scheme 119: Cu-catalyzed synthesis of α-trifluoromethylthio-substituted ketones.
Scheme 120: Trifluoromethylthiolation reactions promoted by diazotriflone and copper.
Scheme 121: Halide activation of N-(trifluoromethylthio)phthalimide.
Scheme 122: The visible light-promoted trifluoromethylthiolation reported by Glorius.
Scheme 123: Synthesis of α-trifluoromethylthioesters via Goossen’s approach.
Scheme 124: Photoinduced trifluoromethylthiolation of diazonium salts.
Scheme 125: Ag-mediated trifluoromethoxylation of aryl stannanes and arylboronic acids.
Scheme 126: Catalytic (hetero)aryl C–H trifluoromethoxylation under visible light.
Scheme 127: Photoinduced C–H-bond trifluromethoxylation of (hetero)arenes.
Recent advances on the transition-metal-catalyzed synthesis of imidazopyridines: an updated coverage
- Gagandeep Kour Reen,
- Ashok Kumar and
- Pratibha Sharma
Beilstein J. Org. Chem. 2019, 15, 1612–1704, doi:10.3762/bjoc.15.165
Graphical Abstract
Figure 1: Various drugs having IP nucleus.
Figure 2: Participation percentage of various TMs for the syntheses of IPs.
Scheme 1: CuI–NaHSO4·SiO2-catalyzed synthesis of imidazo[1,2-a]pyridines.
Scheme 2: Experimental examination of reaction conditions.
Scheme 3: One-pot tandem reaction for the synthesis of 2-haloimidazopyridines.
Scheme 4: Mechanistic scheme for the synthesis of 2-haloimidazopyridine.
Scheme 5: Copper-MOF-catalyzed three-component reaction (3-CR) for imidazo[1,2-a]pyridines.
Scheme 6: Mechanism for copper-MOF-driven synthesis.
Scheme 7: Heterogeneous synthesis via titania-supported CuCl2.
Scheme 8: Mechanism involving oxidative C–H functionalization.
Scheme 9: Heterogeneous synthesis of IPs.
Scheme 10: One-pot regiospecific synthesis of imidazo[1,2-a]pyridines.
Scheme 11: Vinyl azide as an unprecedented substrate for imidazo[1,2-a]pyridines.
Scheme 12: Radical pathway.
Scheme 13: Cu(I)-catalyzed transannulation approach for imidazo[1,5-a]pyridines.
Scheme 14: Plausible radical pathway for the synthesis of imidazo[1,5-a]pyridines.
Scheme 15: A solvent-free domino reaction for imidazo[1,2-a]pyridines.
Scheme 16: Cu-NPs-mediated synthesis of imidazo[1,2-a]pyridines.
Scheme 17: CuI-catalyzed synthesis of isoxazolylimidazo[1,2-a]pyridines.
Scheme 18: Functionalization of 4-bromo derivative via Sonogashira coupling reaction.
Scheme 19: A plausible reaction pathway.
Scheme 20: Cu(I)-catalyzed intramolecular oxidative C–H amidation reaction.
Scheme 21: One-pot synthetic reaction for imidazo[1,2-a]pyridine.
Scheme 22: Plausible reaction mechanism.
Scheme 23: Cu(OAc)2-promoted synthesis of imidazo[1,2-a]pyridines.
Scheme 24: Mechanism for aminomethylation/cycloisomerization of propiolates with imines.
Scheme 25: Three-component synthesis of imidazo[1,2-a]pyridines.
Figure 3: Scope of pyridin-2(1H)-ones and acetophenones.
Scheme 26: CuO NPS-promoted A3 coupling reaction.
Scheme 27: Cu(II)-catalyzed C–N bond formation reaction.
Scheme 28: Mechanism involving Chan–Lam/Ullmann coupling.
Scheme 29: Synthesis of formyl-substituted imidazo[1,2-a]pyridines.
Scheme 30: A tandem sp3 C–H amination reaction.
Scheme 31: Probable mechanistic approach.
Scheme 32: Dual catalytic system for imidazo[1,2-a]pyridines.
Scheme 33: Tentative mechanism.
Scheme 34: CuO/CuAl2O4/ᴅ-glucose-promoted 3-CCR.
Scheme 35: A tandem CuOx/OMS-2-based synthetic strategy.
Figure 4: Biomimetic catalytic oxidation in the presence of electron-transfer mediators (ETMs).
Scheme 36: Control experiment.
Scheme 37: Copper-catalyzed C(sp3)–H aminatin reaction.
Scheme 38: Reaction of secondary amines.
Scheme 39: Probable mechanistic pathway.
Scheme 40: Coupling reaction of α-azidoketones.
Scheme 41: Probable pathway.
Scheme 42: Probable mechanism with free energy calculations.
Scheme 43: MCR for cyanated IP synthesis.
Scheme 44: Substrate scope for the reaction.
Scheme 45: Reaction mechanism.
Scheme 46: Probable mechanistic pathway for Cu/ZnAl2O4-catalyzed reaction.
Scheme 47: Copper-catalyzed double oxidative C–H amination reaction.
Scheme 48: Application towards different coupling reactions.
Scheme 49: Reaction mechanism.
Scheme 50: Condensation–cyclization approach for the synthesis of 1,3-diarylated imidazo[1,5-a]pyridines.
Scheme 51: Optimized reaction conditions.
Scheme 52: One-pot 2-CR.
Scheme 53: One-pot 3-CR without the isolation of chalcone.
Scheme 54: Copper–Pybox-catalyzed cyclization reaction.
Scheme 55: Mechanistic pathway catalyzed by Cu–Pybox complex.
Scheme 56: Cu(II)-promoted C(sp3)-H amination reaction.
Scheme 57: Wider substrate applicability for the reaction.
Scheme 58: Plausible reaction mechanism.
Scheme 59: CuI assisted C–N cross-coupling reaction.
Scheme 60: Probable reaction mechanism involving sp3 C–H amination.
Scheme 61: One-pot MCR-catalyzed by CoFe2O4/CNT-Cu.
Scheme 62: Mechanistic pathway.
Scheme 63: Synthetic scheme for 3-nitroimidazo[1,2-a]pyridines.
Scheme 64: Plausible mechanism for CuBr-catalyzed reaction.
Scheme 65: Regioselective synthesis of halo-substituted imidazo[1,2-a]pyridines.
Scheme 66: Synthesis of 2-phenylimidazo[1,2-a]pyridines.
Scheme 67: Synthesis of diarylated compounds.
Scheme 68: CuBr2-mediated one-pot two-component oxidative coupling reaction.
Scheme 69: Decarboxylative cyclization route to synthesize 1,3-diarylimidazo[1,5-a]pyridines.
Scheme 70: Mechanistic pathway.
Scheme 71: C–H functionalization reaction of enamines to produce diversified heterocycles.
Scheme 72: A plausible mechanism.
Scheme 73: CuI-promoted aerobic oxidative cyclization reaction of ketoxime acetates and pyridines.
Scheme 74: CuI-catalyzed pathway for the formation of imidazo[1,2-a]pyridine.
Scheme 75: Mechanistic pathway.
Scheme 76: Mechanistic rationale for the synthesis of products.
Scheme 77: Copper-catalyzed synthesis of vinyloxy-IP.
Scheme 78: Regioselective product formation with propiolates.
Scheme 79: Proposed mechanism for vinyloxy-IP formation.
Scheme 80: Regioselective synthesis of 3-hetero-substituted imidazo[1,2-a]pyridines with different reaction su...
Scheme 81: Mechanistic pathway.
Scheme 82: CuI-mediated synthesis of 3-formylimidazo[1,2-a]pyridines.
Scheme 83: Radical pathway for 3-formylated IP synthesis.
Scheme 84: Pd-catalyzed urea-cyclization reaction for IPs.
Scheme 85: Pd-catalyzed one-pot-tandem amination and intramolecular amidation reaction.
Figure 5: Scope of aniline nucleophiles.
Scheme 86: Pd–Cu-catalyzed Sonogashira coupling reaction.
Scheme 87: One-pot amide coupling reaction for the synthesis of imidazo[4,5-b]pyridines.
Scheme 88: Urea cyclization reaction for the synthesis of two series of pyridines.
Scheme 89: Amidation reaction for the synthesis of imidazo[4,5-b]pyridines.
Figure 6: Amide scope.
Scheme 90: Pd NPs-catalyzed 3-component reaction for the synthesis of 2,3-diarylated IPs.
Scheme 91: Plausible mechanistic pathway for Pd NPs-catalyzed MCR.
Scheme 92: Synthesis of chromenoannulated imidazo[1,2-a]pyridines.
Scheme 93: Mechanism for the synthesis of chromeno-annulated IPs.
Scheme 94: Zinc oxide NRs-catalyzed synthesis of imidazo[1,2-a]azines/diazines.
Scheme 95: Zinc oxide-catalyzed isocyanide based GBB reaction.
Scheme 96: Reaction pathway for ZnO-catalyzed GBB reaction.
Scheme 97: Mechanistic pathway.
Scheme 98: ZnO NRs-catalyzed MCR for the synthesis of imidazo[1,2-a]azines.
Scheme 99: Ugi type GBB three-component reaction.
Scheme 100: Magnetic NPs-catalyzed synthesis of imidazo[1,2-a]pyridines.
Scheme 101: Regioselective synthesis of 2-alkoxyimidazo[1,2-a]pyridines catalyzed by Fe-SBA-15.
Scheme 102: Plausible mechanistic pathway for the synthesis of 2-alkoxyimidazopyridine.
Scheme 103: Iron-catalyzed synthetic approach.
Scheme 104: Iron-catalyzed aminooxygenation reaction.
Scheme 105: Mechanistic pathway.
Scheme 106: Rh(III)-catalyzed double C–H activation of 2-substituted imidazoles and alkynes.
Scheme 107: Plausible reaction mechanism.
Scheme 108: Rh(III)-catalyzed non-aromatic C(sp2)–H bond activation–functionalization for the synthesis of imid...
Scheme 109: Reactivity and selectivity of different substrates.
Scheme 110: Rh-catalyzed direct C–H alkynylation by Li et al.
Scheme 111: Suggested radical mechanism.
Scheme 112: Scandium(III)triflate-catalyzed one-pot reaction and its mechanism for the synthesis of benzimidazo...
Scheme 113: RuCl3-assisted Ugi-type Groebke–Blackburn condensation reaction.
Scheme 114: C-3 aroylation via Ru-catalyzed two-component reaction.
Scheme 115: Regioselective synthetic mechanism.
Scheme 116: La(III)-catalyzed one-pot GBB reaction.
Scheme 117: Mechanistic approach for the synthesis of imidazo[1,2-a]pyridines.
Scheme 118: Synthesis of imidazo[1,2-a]pyridine using LaMnO3 NPs under neat conditions.
Scheme 119: Mechanistic approach.
Scheme 120: One-pot 3-CR for regioselective synthesis of 2-alkoxy-3-arylimidazo[1,2-a]pyridines.
Scheme 121: Formation of two possible products under optimization of the catalysts.
Scheme 122: Mechanistic strategy for NiFe2O4-catalyzed reaction.
Scheme 123: Two-component reaction for synthesizing imidazodipyridiniums.
Scheme 124: Mechanistic scheme for the synthesis of imidazodipyridiniums.
Scheme 125: CuI-catalyzed arylation of imidazo[1,2-a]pyridines.
Scheme 126: Mechanism for arylation reaction.
Scheme 127: Cupric acetate-catalyzed double carbonylation approach.
Scheme 128: Radical mechanism for double carbonylation of IP.
Scheme 129: C–S bond formation reaction catalyzed by cupric acetate.
Scheme 130: Cupric acetate-catalyzed C-3 formylation approach.
Scheme 131: Control experiments for signifying the role of DMSO and oxygen.
Scheme 132: Mechanism pathway.
Scheme 133: Copper bromide-catalyzed CDC reaction.
Scheme 134: Extension of the substrate scope.
Scheme 135: Plausible radical pathway.
Scheme 136: Transannulation reaction for the synthesis of imidazo[1,5-a]pyridines.
Scheme 137: Plausible reaction pathway for denitrogenative transannulation.
Scheme 138: Cupric acetate-catalyzed C-3 carbonylation reaction.
Scheme 139: Plausible mechanism for regioselective C-3 carbonylation.
Scheme 140: Alkynylation reaction at C-2 of 3H-imidazo[4,5-b]pyridines.
Scheme 141: Two-way mechanism for C-2 alkynylation of 3H-imidazo[4,5-b]pyridines.
Scheme 142: Palladium-catalyzed SCCR approach.
Scheme 143: Palladium-catalyzed Suzuki coupling reaction.
Scheme 144: Reaction mechanism.
Scheme 145: A phosphine free palladium-catalyzed synthesis of C-3 arylated imidazopyridines.
Scheme 146: Palladium-mediated Buchwald–Hartwig cross-coupling reaction.
Figure 7: Structure of the ligands optimized.
Scheme 147: Palladium acetate-catalyzed direct arylation of imidazo[1,2-a]pyridines.
Scheme 148: Palladium acetate-catalyzed mechanistic pathway.
Scheme 149: Palladium acetate-catalyzed regioselective arylation reported by Liu and Zhan.
Scheme 150: Mechanism for selective C-3 arylation of IP.
Scheme 151: Pd(II)-catalyzed alkenylation reaction with styrenes.
Scheme 152: Pd(II)-catalyzed alkenylation reaction with acrylates.
Scheme 153: A two way mechanism.
Scheme 154: Double C–H activation reaction catalyzed by Pd(OAc)2.
Scheme 155: Probable mechanism.
Scheme 156: Palladium-catalyzed decarboxylative coupling.
Scheme 157: Mechanistic cycle for decarboxylative arylation reaction.
Scheme 158: Ligand-free approach for arylation of imidazo[1,2-a]pyridine-3-carboxylic acids.
Scheme 159: Mechanism for ligandless arylation reaction.
Scheme 160: NHC-Pd(II) complex assisted arylation reaction.
Scheme 161: C-3 arylation of imidazo[1,2-a]pyridines with aryl bromides catalyzed by Pd(OAc)2.
Scheme 162: Pd(II)-catalyzed C-3 arylations with aryl tosylates and mesylates.
Scheme 163: CDC reaction for the synthesis of imidazo[1,2-a]pyridines.
Scheme 164: Plausible reaction mechanism for Pd(OAc)2-catalyzed synthesis of imidazo[1,2-a]pyridines.
Scheme 165: Pd-catalyzed C–H amination reaction.
Scheme 166: Mechanism for C–H amination reaction.
Scheme 167: One-pot synthesis for 3,6-di- or 2,3,6-tri(hetero)arylimidazo[1,2-a]pyridines.
Scheme 168: C–H/C–H cross-coupling reaction of IPs and azoles catalyzed by Pd(II).
Scheme 169: Mechanistic cycle.
Scheme 170: Rh-catalyzed C–H arylation reaction.
Scheme 171: Mechanistic pathway for C–H arylation of imidazo[1,2-a]pyridine.
Scheme 172: Rh(III)-catalyzed double C–H activation of 2-phenylimidazo[1,2-a]pyridines and alkynes.
Scheme 173: Rh(III)-catalyzed mechanistic pathway.
Scheme 174: Rh(III)-mediated oxidative coupling reaction.
Scheme 175: Reactions showing functionalization of the product obtained by the group of Kotla.
Scheme 176: Mechanism for Rh(III)-catalyzed oxidative coupling reaction.
Scheme 177: Rh(III)-catalyzed C–H activation reaction.
Scheme 178: Mechanistic cycle.
Scheme 179: Annulation reactions of 2-arylimidazo[1,2-a]pyridines and alkynes.
Scheme 180: Two-way reaction mechanism for annulations reaction.
Scheme 181: [RuCl2(p-cymene)]2-catalyzed C–C bond formation reaction.
Scheme 182: Reported reaction mechanism.
Scheme 183: Fe(III) catalyzed C-3 formylation approach.
Scheme 184: SET mechanism-catalyzed by Fe(III).
Scheme 185: Ni(dpp)Cl2-catalyzed KTC coupling.
Scheme 186: Pd-catalyzed SM coupling.
Scheme 187: Vanadium-catalyzed coupling of IP and NMO.
Scheme 188: Mechanistic cycle.
Scheme 189: Selective C3/C5–H bond functionalizations by mono and bimetallic systems.
Scheme 190: rGO-Ni@Pd-catalyzed C–H bond arylation of imidazo[1,2-a]pyridine.
Scheme 191: Mechanistic pathway for heterogeneously catalyzed arylation reaction.
Scheme 192: Zinc triflate-catalyzed coupling reaction of substituted propargyl alcohols.
Synthesis of dipolar molecular rotors as linkers for metal-organic frameworks
- Sebastian Hamer,
- Fynn Röhricht,
- Marius Jakoby,
- Ian A. Howard,
- Xianghui Zhang,
- Christian Näther and
- Rainer Herges
Beilstein J. Org. Chem. 2019, 15, 1331–1338, doi:10.3762/bjoc.15.132
- subsequent direct conversion of the TMS-protected acetylenes to the dicarboxylic acids using a method of Kondo and co-workers [42]. Following this procedure, purification of TMS-protected compounds was more convenient as compared to the tedious work-up with carboxylic acid derivatives directly obtained from
Graphical Abstract
Figure 1: Interactions of a pair of dipolar rotors in different orientations. The axes of the rotors are para...
Figure 2: Structures of molecular dipolar rotors/linker molecules 1–5.
Scheme 1: General synthetic strategy to prepare the dipolar rotors 1–5.
Scheme 2: Synthesis of 3,3'-(2,3-difluoro-1,4-phenylene)dipropiolic acid (1) starting with diiodination of 1,...
Scheme 3: Synthesis of 3,3'-(5,6-Difluoro-2,1,3-benzothiadiazol-4,7-diyl)dipropiolic acid (2) and 3,3'-(5,6-D...
Scheme 4: Synthesis of 3,3'-(5,6-dicyano-1,3-benzodioxole-4,7-diyl)dipropiolic acid (4) and 3,3'-(6,7-dicyano...
Synthesis and selected transformations of 2-unsubstituted 1-(adamantyloxy)imidazole 3-oxides: straightforward access to non-symmetric 1,3-dialkoxyimidazolium salts
- Grzegorz Mlostoń,
- Małgorzata Celeda,
- Katarzyna Urbaniak,
- Marcin Jasiński,
- Vladyslav Bakhonsky,
- Peter R. Schreiner and
- Heinz Heimgartner
Beilstein J. Org. Chem. 2019, 15, 497–505, doi:10.3762/bjoc.15.43
- reactivity analogous to aldonitrones, which enables their conversion via [3 + 2]-cycloadditions with dipolarophiles such as activated ethylenes [8][9], activated acetylenes [10][11] or isocyanates [11][12]. The initially formed [3 + 2]-cycloadducts undergo spontaneous secondary conversions leading to re
Graphical Abstract
Scheme 1: Synthesis of 2-unsubstituted imidazole N-oxides 1 from α-hydroxyiminoketones 2 and formaldimines 3.
Scheme 2: Preparation of adamantyloxyamine (4) and its conversion into N-(adamantyloxy)formaldimine (6a); Ad ...
Scheme 3: Synthesis of 1-(adamantyloxy)imidazole 3-oxides 7a–e and 1-adamantylimidazole 3-oxides 7f,g in acet...
Scheme 4: Deoxygenation of 1-(adamantyloxy)imidazole 3-oxides 7a–d and isomerization of 7b into imidazole-2-o...
Scheme 5: Conversions of imidazole 3-oxides 7a–d into 1-(adamantyloxy)imidazole-2-thiones 10a–d via sulfur tr...
Scheme 6: Syntheses of the non-symmetric 1,3-dialkoxyimidazolium bromides 13a–c and 1-alkyl-3-alkoxyimidazoli...
Scheme 7: Attempted O-adamantylation of imidazole N-oxide 7a with adamantan-1-yl trifluoroacetate and subsequ...
Scheme 8: Synthesis of the symmetric 1,3-di(adamantyloxy)imidazolium bromide (15) and its transformation to 1...
Synthesis and fluorescent properties of N(9)-alkylated 2-amino-6-triazolylpurines and 7-deazapurines
- Andrejs Šišuļins,
- Jonas Bucevičius,
- Yu-Ting Tseng,
- Irina Novosjolova,
- Kaspars Traskovskis,
- Ērika Bizdēna,
- Huan-Tsung Chang,
- Sigitas Tumkevičius and
- Māris Turks
Beilstein J. Org. Chem. 2019, 15, 474–489, doi:10.3762/bjoc.15.41
- the synthetic intermediates obtained in the SNAr reaction (e.g., 6-azido-9-heptyl-2-(piperidin-1-yl)purine (6b)) exists in both tetrazolo- and azido-tautomeric forms in CD3CN solution. The presence of the latter permits the CuAAC reaction with terminal acetylenes and gave a rise to the title compounds
Graphical Abstract
Figure 1: Examples of fluorescent purine/7-deazapurine derivatives.
Scheme 1: General synthetic routes for the compounds 5, 7–9, 10 and 11. Method A: alkyl halogenide, MeCN or D...
Figure 2: 1H NMR spectra of compound 6b in CD3CN at different temperatures (300 MHz, c = 12.5 mg/mL); a, b, c...
Figure 3: Comparison of 1H NMR spectra of compounds 8a and 5 (300 MHz, CDCl3).
Figure 4: a) Experimental UV–vis absorption spectra (lines) with computed theoretical absorption bands (colum...
Figure 5: Photos of compound 8c (A and B) and compound 11c (C and D) in THF, CHCl3, DMSO, MeCN and MeOH befor...
Figure 6: a) Fluorescence spectra of compounds 8c (λexc = 360 nm) and 11c (λexc = 370 nm) in solvents of diff...
Figure 7: Energy diagram for the frontier molecular orbitals of compounds 8a, 8c, 11a and 11c.
Figure 8: Labeled MCF-7 cells using compound 9 (C,D) and unlabeled MCF-7 cells (A,B) in microscope (2 h, c(9)...
Ring-closing-metathesis-based synthesis of annellated coumarins from 8-allylcoumarins
- Christiane Schultze and
- Bernd Schmidt
Beilstein J. Org. Chem. 2018, 14, 2991–2998, doi:10.3762/bjoc.14.278
- [62] of furanyl carbene complexes and acetylenes [63]. Angelicin (3a) was also obtained via RCM of 8-(1-propenyl)-7-vinyloxycoumarin, but the synthesis of this precursor required four steps, starting from umbelliferone, and proceeded only with moderate regioselectivity for the second step [47]. Next
Graphical Abstract
Figure 1: Illustration of coumarin taxonomy.
Scheme 1: Synthesis of oxepin-2-one-annellated coumarins 13 by RCM of acrylates 12.
Scheme 2: Attempted synthesis of pyran-2-one-annellated coumarin 15d via isomerization-RCM.
Scheme 3: Synthesis of aza-annellated coumarin 21 and attempted synthesis of indole 22.
Generation of 1,2-oxathiolium ions from (arysulfonyl)- and (arylsulfinyl)allenes in Brønsted acids. NMR and DFT study of these cations and their reactions
- Stanislav V. Lozovskiy,
- Alexander Yu. Ivanov,
- Olesya V. Khoroshilova and
- Aleksander V. Vasilyev
Beilstein J. Org. Chem. 2018, 14, 2897–2906, doi:10.3762/bjoc.14.268
- explored in organic synthesis for the construction of various molecules [1][2][3][4][5][6][7]. In particular, arylsulfonyl (ArSO2) allenes are usefull building blocks in miscellaneous transformations. For instance, addition of such allenes to Michael acceptors leading to terminal acetylenes has been
Graphical Abstract
Scheme 1: (Arylsulfinyl)allenes 1 and (arylsulfonyl)allenes 2 used in this study.
Figure 1: X-ray crystal structures of compounds 2h (CCDC 1843276), 3e (CCDC 1843277), 5c (CCDC 1580895), 7b (...
Scheme 2: Plausible reaction mechanisms of transformations of allene 2a in Brønsted acids.
Scheme 3: Selective formation of butadienes 3a–h from allenes 2a–h.
Scheme 4: Reactions of allenes 2 in the system HFIP/TfOH followed by interaction with nucleophiles leading to...
Scheme 5: Formation of thiochromene 1,1-dioxides 5a–c from allenes 2a,c,d.
Scheme 6: Formation of (arylsulfonyl)acetones 6a,b from allenes 2h,j in TfOH (100 °C, 0.5 h) followed by hydr...
Scheme 7: Reactions of (arylsulfinyl)allenes 1a,b under superelectrophilic activation.
Transition metal-free oxidative and deoxygenative C–H/C–Li cross-couplings of 2H-imidazole 1-oxides with carboranyl lithium as an efficient synthetic approach to azaheterocyclic carboranes
- Lidia A. Smyshliaeva,
- Mikhail V. Varaksin,
- Pavel A. Slepukhin,
- Oleg N. Chupakhin and
- Valery N. Charushin
Beilstein J. Org. Chem. 2018, 14, 2618–2626, doi:10.3762/bjoc.14.240
- of promising heterocyclic carboranes: (i) condensation of decaborane (B10H14) with substituted acetylenes [27][28][29][30], (ii) carboryne-based cycloaddition reactions [31][32][33], and (iii) C–X/C–M cross coupling of halogenated azaheterocycles (X = Br, Cl, F) with carborane organometallic
Graphical Abstract
Scheme 1: C–H/C–Li cross-coupling reactions of 2H-imidazole 1-oxides 1a–d and carboranyl lithium 2. The react...
Figure 1: The 1H NMR spectra of 1-(5-(4-bromophenyl)-2-ethyl-2-methyl-2H-imidazol-4-yl)-1,2-dicarba-closo-dod...
Figure 2: Fragment of the 2D 1H–13C{1H} HSQC (a) and HMBC (b) spectra of imidazolyl carborane 5d in CDCl3 at ...
Figure 3: Molecular structure of 5d. Selected bond distances (Å) and angles (deg) for molecule 1: C(3)–C(14),...
[3 + 2]-Cycloaddition reaction of sydnones with alkynes
- Veronika Hladíková,
- Jiří Váňa and
- Jiří Hanusek
Beilstein J. Org. Chem. 2018, 14, 1317–1348, doi:10.3762/bjoc.14.113
- )sydnones with DMAD for which positive Hammett ρ-values were observed [54][55]. On the other hand Huisgen and Gotthardt [54] measured bimolecular rate constants for the above-mentioned reaction of 4-methyl-3-phenylsydnone and various acetylenes in p-cymene at 140 °C (Table 2) and found a reactivity sequence
- constants (k, L·mol–1·s–1) measured for the reaction of 4-methyl-3-phenylsydnone and various acetylenes in p-cymene at 140 °C [54]. Photochemical cycloaddition of N-phenylsydnones with DMAD. Thermal cycloaddition of sydnones with terminal alkynes. Thermal cycloaddition of sydnones with internal non
Graphical Abstract
Scheme 1: Thermal reaction of sydnones with symmetrical alkynes.
Scheme 2: Reaction of sydnones with strained cycloalkynes.
Scheme 3: Reaction of sydnones with didehydrobenzenes.
Scheme 4: Formation of isomeric pyrazole dicarboxylates.
Scheme 5: Mechanism of thermal cycloaddition between sydnones and alkynes.
Scheme 6: Mechanism of photochemical reaction of sydnones with symmetrical alkynes.
Scheme 7: HOMO–LUMO diagram for thermal [3 + 2]-cycloaddition of sydnones with alkynes.
Scheme 8: Synthetic strategy leading to 1,2-disubstituted pyrazoles.
Scheme 9: Unsuccessful reaction with phenylpropiolic acid.
Scheme 10: Synthetic strategy leading to 1,4,5-trisubstituted pyrazoles.
Scheme 11: Reaction of sydnones carrying in position 4- six-membered 2-N-heterocyclic ring.
Scheme 12: Strain-promoted sydnone alkyne cycloaddition (SPSAC).
Scheme 13: Synthesis of a key intermediate of niraparib.
Scheme 14: Reaction of sydnones with 1,3-/1,4-benzdiyne equivalents.
Scheme 15: Reaction of sydnones with heterocyclic strained cycloalkynes.
Scheme 16: Mono-copper catalyzed cycloaddition reaction.
Scheme 17: Di-copper catalyzed cycloaddition reaction.
Atom-economical group-transfer reactions with hypervalent iodine compounds
- Andreas Boelke,
- Peter Finkbeiner and
- Boris J. Nachtsheim
Beilstein J. Org. Chem. 2018, 14, 1263–1280, doi:10.3762/bjoc.14.108
- coupled with the alkyne under palladium catalysis. A broad range of TMS-substituted acetylenes 29 was converted efficiently under the optimized reaction conditions, forming the desired arylacetylenes 30 in good yields with high stereoselectivity. The applicable substrate scope is rather broad including
Graphical Abstract
Scheme 1: Overview of different types of iodane-based group-transfer reactions and their atom economy based o...
Scheme 2: (a) Structure of diaryliodonium salts 1. (b) Diarylation of a suitable substrate A with one equival...
Scheme 3: Synthesis of biphenyls 3 and 3’ with symmetrical diaryliodonium salts 1.
Scheme 4: Synthesis of diaryl thioethers 5.
Scheme 5: Synthesis of two distinct S-aryl dithiocarbamates 7 and 7’ from one equivalent of diaryliodonium sa...
Scheme 6: Synthesis of substituted isoindolin-1-ones 9 from 2-formylbenzonitrile 8 and the postulated reactio...
Scheme 7: Domino C-/N-arylation of indoles 10.
Scheme 8: Domino modification of N-heterocycles 12 via in situ-generated directing groups.
Scheme 9: Synthesis of triarylamines 17 through a double arylation of anilines.
Scheme 10: Selective conversion of novel aryl(imidazolyl)iodonium salts 1b to 1,5-disubstituted imidazoles 18.
Scheme 11: Selected examples for the application of cyclic diaryliodonium salts 19.
Scheme 12: Tandem oxidation–arylation sequence with (dicarboxyiodo)benzenes 20.
Scheme 13: Oxidative α-arylation via the transfer of an intact 2-iodoaryl group.
Scheme 14: Tandem ortho-iodination/O-arylation cascade with PIDA derivatives 20b.
Scheme 15: Synthesis of meta-N,N-diarylaminophenols 28 and the postulated mechanism.
Scheme 16: (Dicarboxyiodo)benzene-mediated metal-catalysed C–H amination and arylation.
Scheme 17: Postulated mechanism for the amination–arylation sequence.
Scheme 18: Auto-amination and cross-coupling of PIDA derivatives 20c.
Scheme 19: Tandem C(sp3)–H olefination/C(sp2)–H arylation.
Scheme 20: Atom efficient functionalisations with benziodoxolones 36.
Scheme 21: Atom-efficient synthesis of furans 39 from benziodoxolones 36a and their further derivatisations.
Scheme 22: Oxyalkynylation of diazo compounds 42.
Scheme 23: Enantioselective oxyalkynylation of diazo compounds 42’.
Scheme 24: Iron-catalysed oxyazidation of enamides 45.
Syn-selective silicon Mukaiyama-type aldol reactions of (pentafluoro-λ6-sulfanyl)acetic acid esters with aldehydes
- Anna-Lena Dreier,
- Andrej V. Matsnev,
- Joseph S. Thrasher and
- Günter Haufe
Beilstein J. Org. Chem. 2018, 14, 373–380, doi:10.3762/bjoc.14.25
- [22]. There are not many transformations of aliphatic SF5 compounds described in the literature. Among them are the preparation and derivatization of SF5-aldehydes [23], Diels–Alder reactions [24][25][26], the “click reaction” of SF5-acetylenes with azides to form triazoles [27], and 1,3-dipolar
Graphical Abstract
Scheme 1: Silicon-mediated Mukaiyama-type aldol reaction of octyl 2-(pentafluoro-λ6-sulfanyl)acetate (1) with ...
Figure 1: Newman projections of the syn- and the anti-diastereomeric aldol addition products.
Scheme 2: Mechanism of the formation of aldol addition products.
Scheme 3: Formation of (E)-configured aldol condensation products.
Scheme 4: Anticipated mechanism of formation of aldol condensation products.
Scheme 5: Synthesis of SF5-substituted acetmorpholide 8.
Scheme 6: Intermediate formation of the (Z)-ketene aminal from morpholide 8 with TMSOTf/ Et3N and subsequent ...
Progress in copper-catalyzed trifluoromethylation
- Guan-bao Li,
- Chao Zhang,
- Chun Song and
- Yu-dao Ma
Beilstein J. Org. Chem. 2018, 14, 155–181, doi:10.3762/bjoc.14.11
- Trifluoromethylated acetylenes were widely used in medicinal, agrochemical, and material science. In 2010, Qing and coworkers [60] firstly reported a copper-mediated trifluoromethylation of terminal alkynes using TMSCF3 as a trifluoromethyl source. (Scheme 39). At the beginning of the experiment, undesired diyne
Graphical Abstract
Figure 1: Selected examples of pharmaceutical and agrochemical compounds containing the trifluoromethyl group....
Scheme 1: Introduction of a diamine into copper-catalyzed trifluoromethylation of aryl iodides.
Scheme 2: Addition of a Lewis acid into copper-catalyzed trifluoromethylation of aryl iodides and the propose...
Scheme 3: Trifluoromethylation of heteroaromatic compounds using S-(trifluoromethyl)diphenylsulfonium salts a...
Scheme 4: The preparation of a new trifluoromethylation reagent and its application in trifluoromethylation o...
Scheme 5: Trifluoromethylation of aryl iodides using CF3CO2Na as a trifluoromethyl source.
Scheme 6: Trifluoromethylation of aryl iodides using MTFA as a trifluoromethyl source.
Scheme 7: Trifluoromethylation of aryl iodides using CF3CO2K as a trifluoromethyl source.
Scheme 8: Trifluoromethylation of aryl iodides and heteroaryl bromides using [Cu(phen)(O2CCF3)] as a trifluor...
Scheme 9: Trifluoromethylation of aryl iodides with DFPB and the proposed mechanism.
Scheme 10: Trifluoromethylation of aryl iodides using TCDA as a trifluoromethyl source. Reaction conditions: [...
Scheme 11: The mechanism of trifluoromethylation using Cu(II)(O2CCF2SO2F)2 as a trifluoromethyl source.
Scheme 12: Trifluoromethylation of benzyl bromide reported by Shibata’s group.
Scheme 13: Trifluoromethylation of allylic halides and propargylic halides reported by the group of Nishibayas...
Scheme 14: Trifluoromethylation of propargylic halides reported by the group of Nishibayashi.
Scheme 15: Trifluoromethylation of alkyl halides reported by Nishibayashi’s group.
Scheme 16: Trifluoromethylation of pinacol esters reported by the group of Gooßen.
Scheme 17: Trifluoromethylation of primary and secondary alkylboronic acids reported by the group of Fu.
Scheme 18: Trifluoromethylation of boronic acid derivatives reported by the group of Liu.
Scheme 19: Trifluoromethylation of organotrifluoroborates reported by the group of Huang.
Scheme 20: Trifluoromethylation of aryl- and vinylboronic acids reported by the group of Shibata.
Scheme 21: Trifluoromethylation of arylboronic acids via the merger of photoredox and Cu catalysis.
Scheme 22: Trifluoromethylation of arylboronic acids reported by Sanford’s group. Isolated yield. aYields dete...
Scheme 23: Trifluoromethylation of arylboronic acids and vinylboronic acids reported by the group of Beller. Y...
Scheme 24: Copper-mediated Sandmeyer type trifluoromethylation using Umemoto’s reagent as a trifluoromethylati...
Scheme 25: Copper-mediated Sandmeyer type trifluoromethylation using TMSCF3 as a trifluoromethylation reagent ...
Scheme 26: One-pot Sandmeyer trifluoromethylation reported by the group of Gooßen.
Scheme 27: Copper-catalyzed trifluoromethylation of arenediazonium salts in aqueous media.
Scheme 28: Copper-mediated Sandmeyer trifluoromethylation using Langlois’ reagent as a trifluoromethyl source ...
Scheme 29: Trifluoromethylation of terminal alkenes reported by the group of Liu.
Scheme 30: Trifluoromethylation of terminal alkenes reported by the group of Wang.
Scheme 31: Trifluoromethylation of tetrahydroisoquinoline derivatives reported by Li and the proposed mechanis...
Scheme 32: Trifluoromethylation of phenol derivatives reported by the group of Hamashima.
Scheme 33: Trifluoromethylation of hydrazones reported by the group of Baudoin and the proposed mechanism.
Scheme 34: Trifluoromethylation of benzamides reported by the group of Tan.
Scheme 35: Trifluoromethylation of heteroarenes and electron-deficient arenes reported by the group of Qing an...
Scheme 36: Trifluoromethylation of N-aryl acrylamides using CF3SO2Na as a trifluoromethyl source.
Scheme 37: Trifluoromethylation of aryl(heteroaryl)enol acetates using CF3SO2Na as the source of CF3 and the p...
Scheme 38: Trifluoromethylation of imidazoheterocycles using CF3SO2Na as a trifluoromethyl source and the prop...
Scheme 39: Copper-mediated trifluoromethylation of terminal alkynes using TMSCF3 as a trifluoromethyl source a...
Scheme 40: Improved copper-mediated trifluoromethylation of terminal alkynes reported by the group of Qing.
Scheme 41: Copper-catalyzed trifluoromethylation of terminal alkynes reported by the group of Qing.
Scheme 42: Copper-catalyzed trifluoromethylation of terminal alkynes using Togni’s reagent and the proposed me...
Scheme 43: Copper-catalyzed trifluoromethylation of terminal alkynes using Umemoto’s reagent reported by the g...
Scheme 44: Copper-catalyzed trifluoromethylation of 3-arylprop-1-ynes reported by Xiao and Lin and the propose...
Synthesis and application of trifluoroethoxy-substituted phthalocyanines and subphthalocyanines
- Satoru Mori and
- Norio Shibata
Beilstein J. Org. Chem. 2017, 13, 2273–2296, doi:10.3762/bjoc.13.224
- modification and purification are easy. For example, the synthesis of unsymmetrical TFEO-Pcs, which are also referred to as A3B type phthalocyanines, and their cross-coupling reaction catalyzed by palladium between A3B type TFEO-Pcs and acetylenes have been reported (Scheme 3) [66][67]. A3B type
Graphical Abstract
Scheme 1: Synthesis of trifluoroethoxy-substituted phthalocyanine.
Scheme 2: Synthesis of trifluoroethoxy-substituted binuclear phthalocyanine 5 in Solkane® 365 mfc.
Scheme 3: Synthesis of trifluoroethoxy-substituted unsymmetrical phthalocyanines.
Scheme 4: Synthesis of trifluoroethoxy-substituted phthalocyanine dimers linked at the β-position.
Figure 1: Structure of trifluoroethoxy-substituted phthalocyanine dimers linked at the α-position.
Figure 2: Structure of trifluoroethoxy-substituted dimer via a diacetylene linker.
Figure 3: UV–vis spectra of 9 (A) and 5 (B).
Figure 4: Structure of binuclear phthalocyanines linked by a triazole linker.
Figure 5: Structure of trinuclear phthalocyanines linked by a triazole linker, and windmill-like molecular st...
Scheme 5: Synthesis of trifluoroethoxy-substituted phthalocyanines conjugated with peptides.
Scheme 6: Synthesis of trifluoroethoxy-substituted phthalocyanines conjugated with deoxyribonucleosides.
Scheme 7: Synthesis of trifluoroethoxy-substituted phthalocyanines conjugated with cyclodextrin.
Figure 6: Direction of energy transfer of phthalocyanine–fullerene conjugates.
Scheme 8: Synthesis of fluoropolymer-bearing phthalocyanine side groups.
Scheme 9: Synthesis of trifluoroethoxy-substituted double-decker type phthalocyanines.
Scheme 10: Synthesis of trifluoroethoxy-substituted subphthalocyanine.
Figure 7: Structure of axial ligand substituted subphthalocyanine hybrid dyes.
Scheme 11: Synthesis of subphthalocyanine homodimers.
Scheme 12: Synthesis of subphthalocyanine heterodimers.
Figure 8: Energy transfer between subphthalocyanine units.
Figure 9: Structure of phthalocyanine and subphthalocyanine benzene-fused homodimers.
Scheme 13: Synthesis of a phthalocyanine and subphthalocyanine benzene-fused heterodimer.
Figure 10: X-ray crystallography of Pc-subPc (left) and UV–vis spectra of benzene-fused dimers.
Mechanochemical synthesis of small organic molecules
- Tapas Kumar Achar,
- Anima Bose and
- Prasenjit Mal
Beilstein J. Org. Chem. 2017, 13, 1907–1931, doi:10.3762/bjoc.13.186
- palladium salts (Pd(OAc)2 or Pd(PPh3)4) and DABCO (1,4-diazabicyclo[2.2.2]octane) various acetylenes and aryl halides were coupled to obtain the Sonogashira coupling products in excellent yields (near quantitative, Scheme 10a). The reactions were reported for aliphatic alkynes as well. In Scheme 10b, an
- triazole moiety (Scheme 37a) using benzyl halides, sodium azide and a terminal alkyne via an alumina-supported copper catalyst. Using 10 mol % of Cu/Al2O3, differently substituted phenyl acetylenes and aliphatic alkynes led to 70–96% yield of triazoles [152]. Phenyl boronic acids were also used to
Graphical Abstract
Scheme 1: Mechanochemical aldol condensation reactions [48].
Scheme 2: Enantioselective organocatalyzed aldol reactions under mechanomilling. a) Based on binam-(S)-prolin...
Scheme 3: Mechanochemical Michael reaction [51].
Scheme 4: Mechanochemical organocatalytic asymmetric Michael reaction [52].
Scheme 5: Mechanochemical Morita–Baylis–Hillman (MBH) reaction [53].
Scheme 6: Mechanochemical Wittig reactions [55].
Scheme 7: Mechanochemical Suzuki reaction [56].
Scheme 8: Mechanochemical Suzuki–Miyaura coupling by LAG [57].
Scheme 9: Mechanochemical Heck reaction [59].
Scheme 10: a) Sonogashira coupling under milling conditions. b) The representative example of a double Sonogas...
Scheme 11: Copper-catalyzed CDC reaction under mechanomilling [67].
Scheme 12: Asymmetric alkynylation of prochiral sp3 C–H bonds via CDC [68].
Scheme 13: Fe(III)-catalyzed CDC coupling of 3-benzylindoles [69].
Scheme 14: Mechanochemical synthesis of 3-vinylindoles and β,β-diindolylpropionates [70].
Scheme 15: Mechanochemical C–N bond construction using anilines and arylboronic acids [78].
Scheme 16: Mechanochemical amidation reaction from aromatic aldehydes and N-chloramine [79].
Scheme 17: Mechanochemical CDC between benzaldehydes and benzyl amines [81].
Scheme 18: Mechanochemical protection of -NH2 and -COOH group of amino acids [85].
Scheme 19: Mechanochemical Ritter reaction [87].
Scheme 20: Mechanochemical synthesis of dialkyl carbonates [90].
Scheme 21: Mechanochemical transesterification reaction using basic Al2O3 [91].
Scheme 22: Mechanochemical carbamate synthesis [92].
Scheme 23: Mechanochemical bromination reaction using NaBr and oxone [96].
Scheme 24: Mechanochemical aryl halogenation reactions using NaX and oxone [97].
Scheme 25: Mechanochemical halogenation reaction of electron-rich arenes [88,98].
Scheme 26: Mechanochemical aryl halogenation reaction using trihaloisocyanuric acids [100].
Scheme 27: Mechanochemical fluorination reaction by LAG method [102].
Scheme 28: Mechanochemical Ugi reaction [116].
Scheme 29: Mechanochemical Passerine reaction [116].
Scheme 30: Mechanochemical synthesis of α-aminonitriles [120].
Scheme 31: Mechanochemical Hantzsch pyrrole synthesis [121].
Scheme 32: Mechanochemical Biginelli reaction by subcomponent synthesis approach [133].
Scheme 33: Mechanochemical asymmetric multicomponent reaction[134].
Scheme 34: Mechanochemical Paal–Knorr pyrrole synthesis [142].
Scheme 35: Mechanochemical synthesis of benzothiazole using ZnO nano particles [146].
Scheme 36: Mechanochemical synthesis of 1,2-di-substituted benzimidazoles [149].
Scheme 37: Mechanochemical click reaction using an alumina-supported Cu-catalyst [152].
Scheme 38: Mechanochemical click reaction using copper vial [155].
Scheme 39: Mechanochemical indole synthesis [157].
Scheme 40: Mechanochemical synthesis of chromene [158].
Scheme 41: Mechanochemical synthesis of azacenes [169].
Scheme 42: Mechanochemical oxidative C-P bond formation [170].
Scheme 43: Mechanochemical C–chalcogen bond formation [171].
Scheme 44: Solvent-free synthesis of an organometallic complex.
Scheme 45: Selective examples of mechano-synthesis of organometallic complexes. a) Halogenation reaction of Re...
Scheme 46: Mechanochemical activation of C–H bond of unsymmetrical azobenzene [178].
Scheme 47: Mechanochemical synthesis of organometallic pincer complex [179].
Scheme 48: Mechanochemical synthesis of tris(allyl)aluminum complex [180].
Scheme 49: Mechanochemical Ru-catalyzed olefin metathesis reaction [181].
Scheme 50: Rhodium(III)-catalyzed C–H bond functionalization under mechanochemical conditions [182].
Scheme 51: Mechanochemical Csp2–H bond amidation using Ir(III) catalyst [183].
Scheme 52: Mechanochemical Rh-catalyzed Csp2–X bond formation [184].
Scheme 53: Mechanochemical Pd-catalyzed C–H activation [185].
Scheme 54: Mechanochemical Csp2–H bond amidation using Rh catalyst.
Scheme 55: Mechanochemical synthesis of indoles using Rh catalyst [187].
Scheme 56: Mizoroki–Heck reaction of aminoacrylates with aryl halide in a ball-mill [58].
Scheme 57: IBX under mechanomilling conditions [8].
Scheme 58: Thiocarbamoylation of anilines; trapping of reactive aryl-N-thiocarbamoylbenzotriazole intermediate...
Transition-metal-free one-pot synthesis of alkynyl selenides from terminal alkynes under aerobic and sustainable conditions
- Adrián A. Heredia and
- Alicia B. Peñéñory
Beilstein J. Org. Chem. 2017, 13, 910–918, doi:10.3762/bjoc.13.92
- acetylenes. Keywords: alkynyl selenide; electrophilic cyclization; nucleophilic substitution; potassium selenocyanate; terminal alkynes; Introduction Alkynyl selenides, as many other selenium compounds, have potential anti-oxidant activities, and may play a role in certain diseases such as cancer, heart
Graphical Abstract
Scheme 1: One-pot synthesis of vinyl and alkynyl selenides.
Scheme 2: Effect of t-BuOK on the formation of n-octyl alkynyl selenide 5a.
Scheme 3: Effect of reactants concentration on alkynyl selenide formation.
Scheme 4: Synthesis of N-ethyl-2-(n-octylselanyl)-1H-indole (9) and 3-iodo-2-(n-octylselanyl)benzofuran (10).
Scheme 5: Control reactions and mechanistic study.
Scheme 6: Proposed mechanism for the formation of selenides 5.
Scheme 7: Proposed mechanism for the formation of indole 9.
Nucleophilic and electrophilic cyclization of N-alkyne-substituted pyrrole derivatives: Synthesis of pyrrolopyrazinone, pyrrolotriazinone, and pyrrolooxazinone moieties
- Işıl Yenice,
- Sinan Basceken and
- Metin Balci
Beilstein J. Org. Chem. 2017, 13, 825–834, doi:10.3762/bjoc.13.83
- presence of silver nitrate. The synthesized acetylenes 10a,b and commercially available acetylenes 10c,d were converted into bromoalkyne derivatives 11a–d according to the literature procedure (Scheme 1) [29][30]. After the successful generation of alkynyl bromides 11a–d, the next step was the synthesis of
Graphical Abstract
Figure 1: Structures of some natural products containing pyrazinone and aminotriazonone skeletons.
Figure 2: Structures of some natural products containing a pyrrolopyrazinone moiety.
Figure 3: N-alkyne substituted pyrrole esters 7a–d.
Scheme 1: Synthesis of N-alkyne substituted methyl 1H-pyrrole-2-carboxylate derivatives 7a–d.
Scheme 2: Nucleophilic cyclization reaction of compounds 7a–d and acetylation of 12c.
Figure 4: Correlations of olefinic proton in 12c and methylene protons in 13c and 16 with the relevant carbon...
Figure 5: Single-crystal X-ray structure of 12c shown with 40% probability displacement ellipsoids.
Scheme 3: Synthesis of 16.
Figure 6: The structure of allene 17 formed during the reaction of 7d with a base.
Scheme 4: Proposed reaction mechanism of nucleophilic cyclization reaction of 7.
Scheme 5: Electrophilic cyclization reactions of 19a–c with iodine.
Figure 7: Single-crystal X-ray structure of 19c shown with 40% probability displacement ellipsoids.
Scheme 6: Proposed reaction mechanism of electrophilic cyclization reaction of 7c.
Figure 8: Potential energy profile related to the formation of pyrrolooxazinone 19c in the polarizable continu...
New approach toward the synthesis of deuterated pyrazolo[1,5-a]pyridines and 1,2,4-triazolo[1,5-a]pyridines
- Aleksey Yu. Vorob’ev,
- Vyacheslav I. Supranovich,
- Gennady I. Borodkin and
- Vyacheslav G. Shubin
Beilstein J. Org. Chem. 2017, 13, 800–805, doi:10.3762/bjoc.13.80
- An efficient and operationally simple synthesis of 7-deuteropyrazolo[1,5-a]pyridine and 7-deutero-1,2,4-triazolo[1,5-a]pyridine derivatives using α-H/D exchange of 1-aminopyridinium cations in basic D2O followed by a 1,3-cycloaddition of acetylenes and nitriles is presented. A high regioselectivity
- -1,2,4-triazolo[1,5-a]pyridine derivatives by H/D exchange of 1-aminopyridinium cations followed by the reaction with acetylenes and nitriles. Results and Discussion N-Aminopyridinium salts are easily available via direct N-amination of parent pyridines. Salt 1a was prepared by N-amination of pyridine
- from N-aminopyridium salts through an H/D exchange in basic D2O solution followed by the cycloaddition reaction with acetylenes (Scheme 1). In the first step, the H/D exchange in 1a has been performed with a 0.67 M solution of K2CO3 in D2O at 80 °C for 5 min. After D2O evaporation and the reaction with
Graphical Abstract
Figure 1: pKa values for N-aminopyridinium cation hydrogen atoms according to DFT M06-2X 6-31+G(d,p) calculat...
Scheme 1: H/D exchange of N-aminopyridinium salts 1a–c and their reaction with acetylenes.
Scheme 2: Possible pathways for the formation of 8.
Figure 2: Relative stability of 3-CO2Et-substituted dihydropyrazolo[1,5-a]pyridines by the M06-2X 6-31+G(d,p)...
Scheme 3: Synthesis of deutero 1,2,4-triazolo[1,5-a]pyridines.
Isoxazole derivatives as new nitric oxide elicitors in plants
- Anca Oancea,
- Emilian Georgescu,
- Florentina Georgescu,
- Alina Nicolescu,
- Elena Iulia Oprita,
- Catalina Tudora,
- Lucian Vladulescu,
- Marius-Constantin Vladulescu,
- Florin Oancea and
- Calin Deleanu
Beilstein J. Org. Chem. 2017, 13, 659–664, doi:10.3762/bjoc.13.65
- -deficient alkene led to the intermediate bromoisoxazoline from which, by loss of HBr, a 3,5-disubstituted isoxazole derivative is formed as major regioisomer [34]. Based on the copper(I)-catalyzed click reactions of organic azides with terminal acetylenes [35], different copper(I)-catalyzed synthetic
Graphical Abstract
Scheme 1: Synthetic route to 3,5-disubstituted isoxazoles.
Dimerization reactions of aryl selenophen-2-yl-substituted thiocarbonyl S-methanides as diradical processes: a computational study
- Michael L. McKee,
- Grzegorz Mlostoń,
- Katarzyna Urbaniak and
- Heinz Heimgartner
Beilstein J. Org. Chem. 2017, 13, 410–416, doi:10.3762/bjoc.13.44
- mechanisms in [3 + 2]-cycloadditions have intensively been studied [16] and recently, a computational study on their appearance in reactions of substituted acetylenes with nitrile oxides has been published [17]. Experimental The Gaussian 09 program system was used for all calculations [18]. The M06-2X
Graphical Abstract
Scheme 1: Generation and typical reactions of the reactive dialkyl and diaryl thiocarbonyl S-methanides 1.
Figure 1: Structures of the reactive intermediates as a diradical 6 or a zwitterion 7 in the course of the di...
Scheme 2: The in situ generation of phenyl selenophen-2-yl S-methanide (8) and its competitive reactions: 1,3...
Figure 2: Potential 1,3-dipolar electrocyclization of thiocabonyl S-methanide 8A. Computed enthalpies (free e...
Figure 3: Stepwise radical dimerization of the reactive thiocarbonyl S-methanide 8. Computed enthalpies (free...
Figure 4: Potential competitive cyclization reactions of the intermediate diradical 12.
Figure 5: a) Spin densities in the conformers 12F and 12G of diradical 12. b) Heteroatom effect on the magnit...
Sydnone C-4 heteroarylation with an indolizine ring via Chichibabin indolizine synthesis
- Florin Albota,
- Mino R. Caira,
- Constantin Draghici,
- Florea Dumitrascu and
- Denisa E. Dumitrescu
Beilstein J. Org. Chem. 2016, 12, 2503–2510, doi:10.3762/bjoc.12.245
- activated acetylenes, the hybrid structures 1 containing a pyrroloazine (pyrroloisoquinoline or pyrrolophthalazine) connected to the sydnone ring through a keto group [5]. As a result, it was of interest to prepare analogous compounds containing a pyrroloazine directly attached to the C-4 position of a
Graphical Abstract
Figure 1: Sydnone-pyrroloazines hybrids 1, indolizine (2), sydnone 3, indolizines attached directly to C-4 of...
Scheme 1: Synthesis of pyridinium bromides 8 and sydnone-indolizine hybrids 9 through the Chichibabin reactio...
Figure 2: The molecular structure of 9d with thermal ellipsoids drawn at the 50% probability level. (a) Inver...
Figure 3: Centrosymmetric C–H···O hydrogen bonded dimeric motif in the crystal of 9d.
Scheme 2: The synthesis and mechanism of formation of sydnone-indolizines 12.
Figure 4: Molecular structure of 12c with atoms represented as thermal ellipsoids at the 50% probability leve...
Figure 5: Intramolecular distortion in 12c.
Practical synthetic strategies towards lipophilic 6-iodotetrahydroquinolines and -dihydroquinolines
- David R. Chisholm,
- Garr-Layy Zhou,
- Ehmke Pohl,
- Roy Valentine and
- Andrew Whiting
Beilstein J. Org. Chem. 2016, 12, 1851–1862, doi:10.3762/bjoc.12.174
- , phosphine additives and strong heating or microwave conditions in order to effect coupling with most acetylenes. Accordingly, it was anticipated that the aryl iodides would be more versatile due to their greater propensity to undergo oxidative additions. Therefore, in this paper we report herein the
Graphical Abstract
Figure 1: Tetrahydroquinoline (THQ) and dihydroquinoline (DHQ) scaffolds to be synthesised.
Scheme 1: Proposed retrosynthesis scheme to access N-isopropyl-THQ 2.
Scheme 2: Synthesis of THQ 3 by initial N-alkylations, followed by PPA-mediated cyclisation.
Scheme 3: Bromination of 3 and attempted halogen exchange of the intermediate 7.
Scheme 4: Synthesis of THQ 10, by initial aza-Michael addition, followed by formation of the tertiary alcohol ...
Scheme 5: Synthesis of THQ 14 by initial acylation, cyclisation with H2SO4 and reduction with borane·dimethyl...
Scheme 6: N-Alkylation of 13 and 14.
Scheme 7: Facile route for the synthesis of 20a.
Scheme 8: Synthesis of THQ 21 and DHQ 22 using borane·dimethyl sulphide complex or DIBAL, respectively.
Figure 2: Simulated structure of 22 indicates a flattened quinoline-like structure. Hartree–Fock calculations...
Scheme 9: Postulated mechanism for the formation of 22 using DIBAL.
Figure 3: Combined, normalised absorption and emission spectra of 28 in chloroform. Absorption spectrum was r...
Scheme 10: Miyaura borylation of 21 and 22 to give crystalline boronic esters 29 and 30.
Figure 4: Comparison of the crystal structures of 29 (left) and 30 (right) as viewed along the plane of the a...
Figure 5: Combined, normalised absorption and emission spectra of 30 in diethyl ether. Absorption spectrum wa...
Multicomponent reactions: A simple and efficient route to heterocyclic phosphonates
- Mohammad Haji
Beilstein J. Org. Chem. 2016, 12, 1269–1301, doi:10.3762/bjoc.12.121
- aldehydes 224 generated terminal acetylenes 226 which cyclized with the second molecule of phosphonate 225 in the presence of Cu(I) to afford (5-methyl-1H-pyrazol-3-yl)phosphonates 230 in 46–81% yields (Scheme 46) [84]. Also, a domino reaction based on the dual reactivity of BOR as a homologation reagent as
- 1,2-dihydropyridine-3-phosphonate 259. Yavari et al. have described the phosphorylation of benzothiazole (263) and isoquinoline (246) through a one-pot three-component reaction with activated acetylenes 260 and diphenyl phosphonate (261) under solvent-free conditions at room temperature (Scheme 54
Graphical Abstract
Scheme 1: The Biginelli condensation.
Scheme 2: The Biginelli reaction of β-ketophosphonates catalyzed by ytterbium triflate.
Scheme 3: Trimethylchlorosilane-mediated Biginelli reaction of diethyl (3,3,3-trifluoropropyl-2-oxo)phosphona...
Scheme 4: Biginelli reaction of dialkyl (3,3,3-trifluoropropyl-2-oxo)phosphonate with trialkyl orthoformates ...
Scheme 5: p-Toluenesulfonic acid-promoted Biginelli reaction of β-ketophosphonates, aryl aldehydes and urea.
Scheme 6: General Kabachnik–Fields reaction for the synthesis of α-aminophosphonates.
Scheme 7: Phthalocyanine–AlCl catalyzed Kabachnik–Fields reaction of N-Boc-piperidin-4-one with diethyl phosp...
Scheme 8: Kabachnik–Fields reaction of isatin with diethyl phosphite and benzylamine.
Scheme 9: Magnetic Fe3O4 nanoparticle-supported phosphotungstic acid-catalyzed Kabachnik–Fields reaction of i...
Scheme 10: The Mg(ClO4)2-catalyzed Kabachnik–Fields reaction of 1-tosylpiperidine-4-one.
Scheme 11: An asymmetric version of the Kabachnik–Fields reaction for the synthesis of α-amino-3-piperidinylph...
Scheme 12: A classical Kabachnik–Fields reaction followed by an intramolecular ring-closing reaction for the s...
Scheme 13: Synthesis of (S)-piperidin-2-phosphonic acid through an asymmetric Kabachnik–Fields reaction.
Scheme 14: A modified diastereoselective Kabachnik–Fields reaction for the synthesis of isoindolin-1-one-3-pho...
Scheme 15: A microwave-assisted Kabachnik–Fields reaction toward isoindolin-1-ones.
Scheme 16: The synthesis of 3-arylmethyleneisoindolin-1-ones through a Horner–Wadsworth–Emmons reaction of Kab...
Scheme 17: An efficient one-pot method for the synthesis of ethyl (2-alkyl- and 2-aryl-3-oxoisoindolin-1-yl)ph...
Scheme 18: FeCl3 and PdCl2 co-catalyzed three-component reaction of 2-alkynylbenzaldehydes, anilines, and diet...
Scheme 19: Three-component reaction of 6-methyl-3-formylchromone (75) with hydrazine derivatives or hydroxylam...
Scheme 20: Three-component reaction of 6-methyl-3-formylchromone (75) with thiourea, guanidinium carbonate or ...
Scheme 21: Three-component reaction of 6-methyl-3-formylchromone (75) with 1,4-bi-nucleophiles in the presence...
Scheme 22: One-pot three-component reaction of 2-alkynylbenzaldehydes, amines, and diethyl phosphonate.
Scheme 23: Lewis acid–surfactant combined catalysts for the one-pot three-component reaction of 2-alkynylbenza...
Scheme 24: Lewis acid catalyzed cyclization of different Kabachnik–Fields adducts.
Scheme 25: Three-component synthesis of N-arylisoquinolone-1-phosphonates 119.
Scheme 26: CuI-catalyzed three-component tandem reaction of 2-(2-formylphenyl)ethanones with aromatic amines a...
Scheme 27: Synthesis of 1,5-benzodiazepin-2-ylphosphonates via ytterbium chloride-catalyzed three-component re...
Scheme 28: FeCl3-catalyzed four-component reaction for the synthesis of 1,5-benzodiazepin-2-ylphosphonates.
Scheme 29: Synthesis of indole bisphosphonates through a modified Kabachnik–Fields reaction.
Scheme 30: Synthesis of heterocyclic bisphosphonates via Kabachnik–Fields reaction of triethyl orthoformate.
Scheme 31: A domino Knoevenagel/phospha-Michael process for the synthesis of 2-oxoindolin-3-ylphosphonates.
Scheme 32: Intramolecular cyclization of phospha-Michael adducts to give dihydropyridinylphosphonates.
Scheme 33: Synthesis of fused phosphonylpyrans via intramolecular cyclization of phospha-Michael adducts.
Scheme 34: InCl3-catalyzed three-component synthesis of (2-amino-3-cyano-4H-chromen-4-yl)phosphonates.
Scheme 35: Synthesis of phosphonodihydropyrans via a domino Knoevenagel/hetero-Diels–Alder process.
Scheme 36: Multicomponent synthesis of phosphonodihydrothiopyrans via a domino Knoevenagel/hetero-Diels–Alder ...
Scheme 37: One-pot four-component synthesis of 1,2-dihydroisoquinolin-1-ylphosphonates under multicatalytic co...
Scheme 38: CuI-catalyzed four-component reactions of methyleneaziridines towards alkylphosphonates.
Scheme 39: Ruthenium–porphyrin complex-catalyzed three-component synthesis of aziridinylphosphonates and its p...
Scheme 40: Copper(I)-catalyzed three-component reaction towards 1,2,3-triazolyl-5-phosphonates.
Scheme 41: Three-component reaction of acylphosphonates, isocyanides and dialkyl acetylenedicarboxylate to aff...
Scheme 42: Synthesis of (4-imino-3,4-dihydroquinazolin-2-yl)phosphonates via an isocyanide-based three-compone...
Scheme 43: Silver-catalyzed three-component synthesis of (2-imidazolin-4-yl)phosphonates.
Scheme 44: Three-component synthesis of phosphonylpyrazoles.
Scheme 45: One-pot three-component synthesis of 3-carbo-5-phosphonylpyrazoles.
Scheme 46: A one-pot two-step method for the synthesis of phosphonylpyrazoles.
Scheme 47: A one-pot method for the synthesis of (5-vinylpyrazolyl)phosphonates.
Scheme 48: Synthesis of 1H-pyrrol-2-ylphosphonates via the [3 + 2] cycloaddition of phosphonate azomethine yli...
Scheme 49: Three-component synthesis of 1H-pyrrol-2-ylphosphonates.
Scheme 50: The classical Reissert reaction.
Scheme 51: One-pot three-component synthesis of N-phosphorylated isoquinolines.
Scheme 52: One-pot three-component synthesis of 1-acyl-1,2-dihydroquinoline-2-phosphonates and 2-acyl-1,2-dihy...
Scheme 53: Three-component reaction of pyridine derivatives with ethyl propiolate and dialkyl phosphonates.
Scheme 54: Three-component reactions for the phosphorylation of benzothiazole and isoquinoline.
Scheme 55: Three-component synthesis of diphenyl [2-(aminocarbonyl)- or [2-(aminothioxomethyl)-1,2-dihydroisoq...
Scheme 56: Three-component stereoselective synthesis of 1,2-dihydroquinolin-2-ylphosphonates and 1,2-dihydrois...
Scheme 57: Diphosphorylation of diazaheterocyclic compounds via a tandem 1,4–1,2 addition of dimethyl trimethy...
Scheme 58: Multicomponent reaction of alkanedials, acetamide and acetyl chloride in the presence of PCl3 and a...
Scheme 59: An oxidative domino three-component synthesis of polyfunctionalized pyridines.
Scheme 60: A sequential one-pot three-component synthesis of polysubstituted pyrroles.
Scheme 61: Three-component decarboxylative coupling of proline with aldehydes and dialkyl phosphites for the s...
Scheme 62: Three-component domino aza-Wittig/phospha-Mannich sequence for the phosphorylation of isatin deriva...
Scheme 63: Stereoselective synthesis of phosphorylated trans-1,5-benzodiazepines via a one-pot three-component...
Scheme 64: One-pot three-component synthesis of phosphorylated 2,6-dioxohexahydropyrimidines.
