Search results
Search for "benzoic acid" in Full Text gives 163 result(s) in Beilstein Journal of Organic Chemistry.
A new approach to silicon rhodamines by Suzuki–Miyaura coupling – scope and limitations
- Thines Kanagasundaram,
- Antje Timmermann,
- Carsten S. Kramer and
- Klaus Kopka
Beilstein J. Org. Chem. 2019, 15, 2569–2576, doi:10.3762/bjoc.15.250
- employed methods: synthesis of the phenyl-substituted silicon rhodamine 22 by Suzuki cross coupling affords the product in a similar yield compared to the addition of phenyllithium to xanthone 12 or the attack of the double metallated bis-aniline 4 (R1 = R2 = Me, M = Mg) to the benzoic acid methyl ester
Graphical Abstract
Scheme 1: Different synthetic approaches to silicon rhodamine dyes.
Scheme 2: Previous work from Calitree [29] and Urano [22,28] on the Suzuki–Miyaura coupling of triflates, derived from x...
Scheme 3: Optimization of cross-coupling conditions of triflate 21, derived from Si-xanthone 12, with boron s...
Scheme 4: Coupling reactions of silicon xanthone 12 with different boron species (23b–30b, 31).
Perspective isomorphs – a new classification of molecular structures based on artistic and chemical concepts
- Jannis Neumann,
- Ansgar Schnurr and
- Hermann A. Wegner
Beilstein J. Org. Chem. 2019, 15, 2319–2326, doi:10.3762/bjoc.15.224
- , however, be placed into a different PI class, when viewed from a different angle. This way, they are perspective isomorphe with 4-fluorobiphenyl or benzoic acid. Nomenclature/coding of perspective isomorphs In order to make the concept of perspective isomorphs practicable and unmistakably understandable
- to a group on the left: 1,2-dihydroxybenzene, 1,2-difluorobenzene, naphthalene. Molecules that can be allocated to a group on the right: diphenylacetylene, 4-fluorobiphenyl, benzoic acid. Molecules that can be allocated to both groups: benzene (not shown), phenol, fluorobenzene (the arrows in red and
Graphical Abstract
Figure 1: Methane, fluoromethane, and difluoromethane in Lewis representation (top, left to right), in ball a...
Figure 2: Multiple allocations of molecules to PI classes. Molecules that can be allocated to a group on the ...
Figure 3: Left: benzene from two different angles, PI code of benzene: PI = 1/2D/C3H3/cX1-1-2-3-X2-X3-X1/h1-3...
Figure 4: The atom carbon by Patrick Borchers (left) and Christoph Kern (right).
Figure 5: Artistic interpretation by Jette Flügge of the atoms hydrogen, carbon, nitrogen, oxygen, and fluori...
Figure 6: Hangings of methane (CH4), fluoromethane (CH3F), and difluoromethane (CH2F2) (from left to right) b...
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
- functionalization reactions. Aryl C–H fluorination with various directing groups: With Pd(OTf)2(MeCN)4 and N-methyl-2-pyrrolidinone (NMP) used as the catalyst system, in 2011 the Yu group [57] described the ortho-fluorination of benzoic acid substrates with a directing group, an electron-deficient removable acidic
- amide (Scheme 19). With this method, both mono- and difluorinated benzoic acid derivatives can be selectively obtained in high yields. In 2014, Pu and co-workers [58] devised the regioselective Pd(PPh3)4-catalyzed electrophilic ortho-fluorination of 2-arylbenzothiazoles with NFSI and ʟ-proline as the
- transformation is proposed in Scheme 33 below. Notably, Cu acts as both a mediator and an oxidizer in this reaction. In the same year, Daugulis et al. [78] presented a Cu-catalyzed selective fluorination of benzoic acid derivatives and benzylamine derivatives assisted by an aminoquinoline auxiliary. With a CuI
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.
Friedel–Crafts approach to the one-pot synthesis of methoxy-substituted thioxanthylium salts
- Kenta Tanaka,
- Yuta Tanaka,
- Mami Kishimoto,
- Yujiro Hoshino and
- Kiyoshi Honda
Beilstein J. Org. Chem. 2019, 15, 2105–2112, doi:10.3762/bjoc.15.208
- the product 3a in 82% yield (Table 1, entries 10–12). Decreasing the amount of TfOH did not improve the yield (Table 1, entry 13). It is suggested that the cyclization and dehydration were efficiently promoted at high temperature. Fortunately, when the reaction was carried out with benzoic acid, which
- is a more easily available substrate in comparison with benzyl chloride, the desired product was obtained in good yield. It was found that the reaction can be applied to not only benzoyl chloride but also to benzoic acid. With the optimized conditions in hand, we investigated the generality of diaryl
Graphical Abstract
Scheme 1: The representative synthesis of thioxanthylium salts.
Figure 1: The generality of diaryl sulfide 1 and benzoyl chloride 2. aThe reaction was carried out with 1a (2...
Figure 2: The UV–vis spectra of thioxanthylium salt (0.1 mM) in CH3CN.
Figure 3: Frontier orbitals of thioxanthylium salts, calculated by DFT at the B3LYP/6-31G(d,p) level of Orca....
Figure 4: UV–vis spectra of thioxanthylium salts 3b and 4b (0.1 mM) in CH3CN.
Figure 5: Structure of thioxanthylium salt 4.
Figure 6: Cyclic voltammograms of thioxanthylium salts 3b and 4b.
A metal-free approach for the synthesis of amides/esters with pyridinium salts of phenacyl bromides via oxidative C–C bond cleavage
- Kesari Lakshmi Manasa,
- Yellaiah Tangella,
- Namballa Hari Krishna and
- Mallika Alvala
Beilstein J. Org. Chem. 2019, 15, 1864–1871, doi:10.3762/bjoc.15.182
- work-up procedures and the requirement of stoichiometric amounts of coupling reagents. On the other hand, benzoylation reactions are usually performed with benzoyl chloride or benzoic anhydride which results in the formation of a substantial amount of undesired chemical waste. Moreover, these benzoic
- acid derivatives are commonly lachrymatory and are inconvenient to handle and store. Over the past decades, the thermodynamic stability of C–C bonds has attracted considerable attention of the synthesis community for the reorganization of organic compound by a sequential C–C cleavage and formation of
Graphical Abstract
Scheme 1: Comparison of our work with previous studies.
Scheme 2: Scope of pyridinium salts and benzylamine substrates. Reaction conditions: 1 (1 mmol), 2 (1 mmol), ...
Scheme 3: Scope of pyridinium salts and benzyl alcohol substrates. Reaction conditions: 1 (1 mmol), 4 (1 mmol...
Scheme 4: Scope of pyridinium salts, primary and secondary amine substrates. Reaction conditions: 1 (1 mmol), ...
Scheme 5: Control experiments for the oxidative cleavage of C–C bonds.
Scheme 6: Plausible reaction mechanism for the synthesis of N-alkylated benzamides 3.
Enantioselective PCCP Brønsted acid-catalyzed aza-Piancatelli rearrangement
- Gabrielle R. Hammersley,
- Meghan F. Nichol,
- Helena C. Steffens,
- Jose M. Delgado,
- Gesine K. Veits and
- Javier Read de Alaniz
Beilstein J. Org. Chem. 2019, 15, 1569–1574, doi:10.3762/bjoc.15.160
- hydrogen bond group afforded the best selectivity (7k). To simplify the purification process, all acid products were transformed into the corresponding methyl ester in situ using (trimethylsilyl)diazomethane. A slight drop in enantioselectivity is observed when the benzoic acid group was moved to the meta
Graphical Abstract
Figure 1: Proposed mechanism of the asymmetric aza-Piancatelli reaction.
Scheme 1: Asymmetric aza-Piancatelli rearrangement with a range of substituted anilines. *To simplify the pur...
Scheme 2: Asymmetric aza-Piancatelli rearrangement with a range of substituted furylcarbinols. *To simplify t...
Multicomponent reactions (MCRs): a useful access to the synthesis of benzo-fused γ-lactams
- Edorta Martínez de Marigorta,
- Jesús M. de Los Santos,
- Ana M. Ochoa de Retana,
- Javier Vicario and
- Francisco Palacios
Beilstein J. Org. Chem. 2019, 15, 1065–1085, doi:10.3762/bjoc.15.104
- acid derivative as one of the substrates of the reaction, together with an amine and a third reagent that provides the carbon atom needed to complete the cyclic moiety. Thus, Shi et al. [76] reacted benzoic acid derivatives 1, amides 2 and DMSO (3) in the presence of DDQ as oxidant and without any
- alkynylpalladium complex 25 in the proposed pathway. Other benzoic acid derivatives such as those bearing a formyl substituent at the ortho position also take part in several multicomponent cyclizations leading to isoindolinones. Thus, 2-formylbenzoate 29, primary amines 2 and terminal alkynes 18 react under
- of the reactive aryne 80 which is first trapped with the nucleophilic isocyanide to form 81 and then with the electrophilic CO2 (78), to furnish an intermediate benzoic acid derivative 82. Intramolecular cyclization would produce the corresponding isobenzofurane 83, which alternatively, could also be
Graphical Abstract
Figure 1: γ-Lactam-derived structures considered in this review.
Figure 2: Alkaloids containing an isoindolinone moiety.
Figure 3: Alkaloids containing the 2-oxindole ring system.
Figure 4: Drugs and biological active compounds containing an isoindolinone moiety.
Figure 5: Drugs and biologically active compounds bearing a 2-oxindole skeleton.
Scheme 1: Three-component reaction of benzoic acid 1, amides 2 and DMSO (3).
Scheme 2: Copper-catalysed three-component reaction of 2-iodobenzoic acids 10, alkynylcarboxylic acids 11 and...
Scheme 3: Proposed mechanism for the formation of methylene isoindolinones 13.
Scheme 4: Copper-catalysed three-component reaction of 2-iodobenzamide 17, terminal alkyne 18 and pyrrole or ...
Scheme 5: Palladium-catalysed three-component reaction of ethynylbenzamides 21, secondary amines 22 and CO (23...
Scheme 6: Proposed mechanism for the formation of methyleneisoindolinones 24.
Scheme 7: Copper-catalysed three-component reaction of formyl benzoate 29, amines 2 and alkynes 18.
Scheme 8: Copper-catalysed three-component reaction of formylbenzoate 29, amines 2 and ketones 31.
Scheme 9: Non-catalysed (A) and phase-transfer catalysed (B) three-component reactions of formylbenzoic acids ...
Scheme 10: Proposed mechanism for the formation of isoindolinones 36.
Scheme 11: Three-component reaction of formylbenzoic acid 33, amines 2 and fluorinated silyl ethers 39.
Scheme 12: Three-component Ugi reaction of 2-formylbenzoic acid (33), diamines 41 and isocyanides 42.
Scheme 13: Non-catalysed (A, B) and chiral phosphoric acid promoted (C) three-component Ugi reactions of formy...
Scheme 14: Proposed mechanism for the enantioselective formation of isoindolinones 46.
Scheme 15: Three-component reaction of benzoic acids 33 or 54, amines 2 and TMSCN (52).
Scheme 16: Several variations of the three-component reaction of formylbenzoic acids 33, amines 2 and isatoic ...
Scheme 17: Proposed mechanism for the synthesis of isoindoloquinazolinones 57.
Scheme 18: Three-component reaction of isobenzofuranone 61, amines 2 and isatoic anhydrides 56.
Scheme 19: Palladium-catalysed three-component reaction of 2-aminobenzamides 59, 2-bromobenzaldehydes 62 and C...
Scheme 20: Proposed mechanism for the palladium-catalysed synthesis of isoindoloquinazolinones 57.
Scheme 21: Four-component reaction of 2-vinylbenzoic acids 67, aryldioazonium tetrafluoroborates 68, DABCO·(SO2...
Scheme 22: Plausible mechanism for the formation of isoindolinones 71.
Scheme 23: Three-component reaction of trimethylsilylaryltriflates 77, isocyanides 42 and CO2 (78).
Scheme 24: Plausible mechanism for the three-component synthesis of phthalimides 79.
Scheme 25: Copper-catalysed three-component reaction of 2-formylbenzonitriles 85, arenes 86 and diaryliodonium...
Scheme 26: Copper-catalysed three-component reaction of 2-formylbenzonitriles 85, diaryliodonium salts 87 and ...
Scheme 27: Proposed mechanism for the formation of 2,3-diarylisoindolinones 88, 89 and 92.
Scheme 28: Palladium-catalysed three-component reaction of chloroquinolinecarbaldehydes 97 with isocyanides 42...
Scheme 29: Palladium-catalysed three-component reaction of imines 99 with CO (23) and ortho-iodoarylimines 100....
Scheme 30: Palladium-catalysed three-component reaction of amines 2 with CO (23) and aryl iodide 105.
Scheme 31: Three-component reaction of 2-ethynylanilines 109, perfluoroalkyl iodides 110 and carbon monoxide (...
Scheme 32: Ultraviolet-induced three-component reaction of N-(2-iodoaryl)acrylamides 113, DABCO·(SO2)2 (69) an...
Scheme 33: Proposed mechanism for the preparation of oxindoles 115.
Scheme 34: Three-component reaction of acrylamide 113, CO (23) and 1,4-benzodiazepine 121.
Scheme 35: Multicomponent reaction of sulfonylacrylamides 123, aryldiazonium tetrafluoroborates 68 and DABCO·(...
Scheme 36: Proposed mechanism for the preparation of oxindoles 124.
Scheme 37: Three-component reaction of N-arylpropiolamides 128, aryl iodides 129 and boronic acids 130.
Scheme 38: Proposed mechanism for the formation of diarylmethylene- and diarylallylideneoxindoles 131 and 132.
Scheme 39: Three-component reaction of cyclohexa-1,3-dione (136), amines 2 and alkyl acetylenedicarboxylates 1...
Scheme 40: Proposed mechanism for the formation of 2-oxindoles 138.
Mechanochemical synthesis of poly(trimethylene carbonate)s: an example of rate acceleration
- Sora Park and
- Jeung Gon Kim
Beilstein J. Org. Chem. 2019, 15, 963–970, doi:10.3762/bjoc.15.93
- milling vessel was placed in a vibrational ball mill and vibrated at 30 Hz. After 2 hours, the vessel was opened and benzoic acid (10 mg) was added followed by an additional 5 minutes of milling to quench the polymerization. To avoid data inconsistency due to inhomogeneity, all material was dissolved in
Graphical Abstract
Scheme 1: Fast trimethylene carbonate polymerization using a solvent-free ball-milling approach.
Figure 1: IR thermometer images showing reactor temperatures at the end of the two individual ball-milling re...
Synthesis of pyrrolidine-based hamamelitannin analogues as quorum sensing inhibitors in Staphylococcus aureus
- Jakob Bouton,
- Kristof Van Hecke,
- Reuven Rasooly and
- Serge Van Calenbergh
Beilstein J. Org. Chem. 2018, 14, 2822–2828, doi:10.3762/bjoc.14.260
- -propanediol (16), which was selectively monoprotected in high yield as TBS ether (Scheme 3) [25]. The remaining alcohol was then substituted for a phthalimide via Mitsunobu reaction. Phthalimide deprotection, acylation with benzoic acid, and removal of the silyl protecting group furnished 10. Fragments 9 and
Graphical Abstract
Figure 1: Structures of hamamelitannin (1), lead compound 2 and target compounds 3.
Scheme 1: Proposed strategy for the synthesis of the target analogues.
Scheme 2: Synthesis of fragment 9. Reagents and conditions: a) phthalimide, Pd2(allyl)2Cl2, ligand 15, Na2CO3...
Scheme 3: Synthesis of fragment 10. Reagents and conditions: a) TBSCl, NaH, THF, rt; b) phthalimide, PPh3, DE...
Scheme 4: Coupling of 9 and 10 and attempted ring-closing metathesis. Reagents and conditions: a) PPh3, DEAD,...
Scheme 5: Synthesis of alternative eastern fragment 23. Reagents and conditions: a) TBSCl, imidazole, CH2Cl2,...
Scheme 6: Synthesis of 4. Reagents and conditions: a) PPh3, DEAD, THF, 0 °C to rt; b) Grubbs–Hoveyda II (5 mo...
Scheme 7: Late stage functionalization of the pyrrolidine nitrogen. Reagents and conditions: A) (masked) alde...
Figure 2: Molecular X-ray structure of 3a, showing thermal displacement ellipsoids at the 50% probability lev...
Synthesis of a tyrosinase inhibitor by consecutive ethenolysis and cross-metathesis of crude cashew nutshell liquid
- Jacqueline Pollini,
- Valentina Bragoni and
- Lukas J. Gooßen
Beilstein J. Org. Chem. 2018, 14, 2737–2744, doi:10.3762/bjoc.14.252
- conducted with crude CNSL, it would lead to the shortened derivatives of all unsaturated components. We reasoned that it might be possible to selectively precipitate the 2-hydroxy-6-(non-8-enyl)benzoic acid (2) from this product mixture and use this as a substrate for a consecutive cross-metathesis with 1
- single run. One-pot cross-metathesis/hydrogenation We next sought for suitable conditions that would allow the cross-metathesis of 2 with 1-hexene to give 2-hydroxy-6-(tridec-8-enyl)benzoic acid (5). When performing the hexenolysis of 2 with 7 equivalents of 1-hexene using 1 mol % of Ru-1 in
- -metathesis and hydrogenation was developed for the synthesis of the tyrosinase inhibitor 3 from the non-edible waste product CNSL. The key step to this process is the ethenolysis of crude CNSL followed by a selective precipitation of 2-hydroxy-6-(non-8-enyl)benzoic acid (2), which transforms the complex
Graphical Abstract
Scheme 1: Targeted conversion of CNSL into a tyrosinase inhibitor.
Scheme 2: Previous synthesis of 2-hydroxy-6-tridecylbenzoic acid by Fu et al.
Scheme 3: Ethenolysis of the crude CNSL.
Figure 1: State-of-the-art metathesis catalysts.
Scheme 4: Overall process in a preparative scale.
The design and synthesis of an antibacterial phenothiazine–siderophore conjugate
- Abed Tarapdar,
- James K. S. Norris,
- Oliver Sampson,
- Galina Mukamolova and
- James T. Hodgkinson
Beilstein J. Org. Chem. 2018, 14, 2646–2650, doi:10.3762/bjoc.14.242
- . However, as our final conjugate contains an aromatic halide we wanted to avoid hydrogenation as the final step and we instead chose to use the para-methoxybenzyl (PMB) protecting group which can be removed under acidic conditions. PMB-protected benzoic acid building block 7 was prepared following a
Graphical Abstract
Figure 1: NDH-2 is a validated target for 1 with an MIC of 1.1 µg/mL against M. tuberculosis.
Scheme 1: Synthesis of phenothiazine-PEG-amine component.
Scheme 2: Synthesis of the azotochelin siderophore component.
Scheme 3: Final conjugation and deprotection to yield a phenothiazine siderophore conjugate.
Quinolines from the cyclocondensation of isatoic anhydride with ethyl acetoacetate: preparation of ethyl 4-hydroxy-2-methylquinoline-3-carboxylate and derivatives
- Nicholas G. Jentsch,
- Jared D. Hume,
- Emily B. Crull,
- Samer M. Beauti,
- Amy H. Pham,
- Julie A. Pigza,
- Jacques J. Kessl and
- Matthew G. Donahue
Beilstein J. Org. Chem. 2018, 14, 2529–2536, doi:10.3762/bjoc.14.229
- acids with triphosgene. Substituted 2-methyl-4-hydroxyquinolines from isatoic anhydrides and ethyl acetoacetate. Mechanistic hypothesis for the cyclocondensation reaction. Quinoline synthesis with ethyl acetylpyruvate. Elaboration of the benzoic acid ethyl ester to the acetic acid residue. Umpolung
Graphical Abstract
Figure 1: Investigational non-catalytic HIV-1 Integrase inhibitors.
Scheme 1: Boehringer Ingelheim retrosynthesis of quinoline 1.
Scheme 2: Quinoline ring condensation strategies.
Scheme 3: Isatoic anhydrides from anthranilic acids with triphosgene.
Scheme 4: Substituted 2-methyl-4-hydroxyquinolines from isatoic anhydrides and ethyl acetoacetate.
Scheme 5: Mechanistic hypothesis for the cyclocondensation reaction.
Scheme 6: Quinoline synthesis with ethyl acetylpyruvate.
Scheme 7: Elaboration of the benzoic acid ethyl ester to the acetic acid residue.
Scheme 8: Umpolung addition of ethoxycarbonyl via a MAC strategy.
Cobalt- and rhodium-catalyzed carboxylation using carbon dioxide as the C1 source
- Tetsuaki Fujihara and
- Yasushi Tsuji
Beilstein J. Org. Chem. 2018, 14, 2435–2460, doi:10.3762/bjoc.14.221
- carboxylation of aryl halides and pseudohalides using CO2 is an important reaction to yield benzoic acid derivatives. In 2009, Martin reported the Pd-catalyzed carboxylation of aryl bromides using ZnEt2 as the reductant [31]. In 2012, we first reported the Ni-catalyzed carboxylation of aryl chlorides and vinyl
- the ligand and AlMe2(OEt) as a reducing agent in a mixture of DMA and 1,1,3,3-tetramethylurea (TMU) as a solvent. Under the reaction conditions, benzene (32a) was converted into benzoic acid (33a, TON: 37) at 85 °C. The monosubstituted arenes such as toluene (32b), fluorobenzene (32c), and
Graphical Abstract
Scheme 1: Optimization of the Co-catalyzed carboxylation of 1a.
Scheme 2: Co-catalyzed carboxylation of propargyl acetates 1.
Scheme 3: Plausible reaction mechanism for the Co-catalyzed carboxylation of propargyl acetates 1.
Scheme 4: Optimization of the Co-catalyzed carboxylation of 3a.
Scheme 5: Co-catalyzed carboxylation of vinyl triflates 3.
Scheme 6: Co-catalyzed carboxylation of a sterically hindered aryl triflate 5.
Scheme 7: Optimization of the Co-catalyzed carboxylation of 7a.
Scheme 8: Scope of the reductive carboxylation of α,β-unsaturated nitriles 7.
Scheme 9: Scope of the carboxylation of α,β-unsaturated carboxamides 9.
Scheme 10: Optimization of the Co-catalyzed carboxylation of 11a.
Scheme 11: Scope of the carboxylation of allylarenes 11.
Scheme 12: Scope of the carboxylation of 1,4-diene derivatives 14.
Scheme 13: Plausible reaction mechanism for the Co-catalyzed C(sp3)–H carboxylation of allylarenes.
Scheme 14: Optimization of the Co-catalyzed carboxyzincation of 16a.
Scheme 15: Derivatization of the carboxyzincated product.
Scheme 16: Co-catalyzed carboxyzincation of alkynes 16.
Scheme 17: Plausible reaction mechanism for the Co-catalyzed carboxyzincation of alkynes 16.
Scheme 18: Co-catalyzed four-component coupling of alkynes 16, acrylates 18, CO2, and zinc.
Scheme 19: Proposed reaction mechanism for the Co-catalyzed four-component coupling.
Scheme 20: Visible-light-driven hydrocarboxylation of alkynes.
Scheme 21: Visible-light-driven synthesis of γ-hydroxybutenolides from ortho-ester-substituted aryl alkynes.
Scheme 22: One-pot synthesis of coumarines and 2-quinolones via hydrocarboxylation/alkyne isomerization/cycliz...
Scheme 23: Proposed reaction mechanism for the Co-catalyzed carboxylative cyclization of ortho-substituted aro...
Scheme 24: Rh-catalyzed carboxylation of arylboronic esters 25.
Scheme 25: Rh-catalyzed carboxylation of alkenylboronic esters 27.
Scheme 26: Plausible reaction mechanism for the Rh-catalyzed carboxylation of arylboronic esters 25.
Scheme 27: Ligand effect on the Rh-catalyzed carboxylation of 2-phenylpyridine 29a.
Scheme 28: Rh-catalyzed chelation-assisted C(sp2)–H bond carboxylation with CO2.
Scheme 29: Reaction mechanism for the Rh-catalyzed C(sp2)–H carboxylation of 2-pyridylarenes 29.
Scheme 30: Carboxylation of C(sp2)–H bond with CO2.
Scheme 31: Carboxylation of C(sp2)–H bond with CO2.
Scheme 32: Reaction mechanism for the Rh-catalyzed C(sp2)–H carboxylation of 2-arylphenols 34.
Scheme 33: Hydrocarboxylation of styrene derivatives with CO2.
Scheme 34: Hydrocarboxylation of α,β-unsaturated esters with CO2.
Scheme 35: Asymmetric hydrocarboxylation of α,β-unsaturated esters with CO2.
Scheme 36: Proposed reaction mechanism for the Rh-catalyzed hydrocarboxylation of C–C double bonds with CO2.
Scheme 37: Visible-light-driven hydrocarboxylation with CO2.
Scheme 38: Visible-light-driven Rh-catalyzed hydrocarboxylation of C–C double bonds with CO2.
Scheme 39: Optimization of reaction conditions on the Rh-catalyzed [2 + 2 + 2] cycloaddition of diyne 42a and ...
Scheme 40: [2 + 2 + 2] Cycloaddition of diyne and CO2.
Scheme 41: Proposed reaction pathways for the Rh-catalyzed [2 + 2 + 2] cycloaddition of diyne and CO2.
Synthesis of diamido-bridged bis-pillar[5]arenes and tris-pillar[5]arenes for construction of unique [1]rotaxanes and bis-[1]rotaxanes
- Ying Han,
- Li-Ming Xu,
- Cui-Yun Nie,
- Shuo Jiang,
- Jing Sun and
- Chao-Guo Yan
Beilstein J. Org. Chem. 2018, 14, 1660–1667, doi:10.3762/bjoc.14.142
- sequential alkylation of ω-bromoalkoxy-substituted pillar[5]arenes with methyl or ethyl p-hydroxybenzoate followed by a hydrolytic reaction under basic conditions. Under catalysis of HOBt/EDCl, the amidation reaction of pillar[5]arene mono(oxybutoxy)benzoic acid with monoamido-functionalized pillar[5]arenes
- ]arene di(oxybutoxy)benzoic acid with monoamido-functionalized pillar[5]arenes resulted in the diamido-bridged tris-pillar[5]arenes, which successfully form the unique bis-[1]rotaxanes bearing longer than diaminopropylene diamido bridges. Keywords: bis-[1]rotaxane; mechanically interlocked molecule
- have a longer chain functionalized group and a large macrocycle, which enabled them to be a good candidate as an efficient terminal stopper for the construction of rotaxanes. Therefore, the amidation reaction of pillar[5]arene mono(oxybutoxy)benzoic acid 3a with our previously reported amido
Graphical Abstract
Scheme 1: Synthesis of pillar[5]arene mono(oxyalkoxy)benzoic acids 3a–c.
Figure 1: single crystal structure of pillar[5]arene 2a.
Figure 2: Single crystal structure of pillar[5]arene 2f.
Scheme 2: Synthesis of diamido-bridged bis-pillar[5]arenes 5a–d.
Figure 3: The 2D NOSEY spectrum of bis-pillar[5]arene 5d.
Scheme 3: Synthesis of pillar[5]arene di(oxyalkoxy)benzoic acid 8.
Figure 4: Single crystal structure of pillar[5]arene 7.
Scheme 4: Synthesis of diamido-bridged tris-pillar[5]arenes 9a–d.
Figure 5: The 2D NOSEY spectra of tris-pillar[5]arene 9d.
Anomeric modification of carbohydrates using the Mitsunobu reaction
- Julia Hain,
- Patrick Rollin,
- Werner Klaffke and
- Thisbe K. Lindhorst
Beilstein J. Org. Chem. 2018, 14, 1619–1636, doi:10.3762/bjoc.14.138
- , conveniently, mildly and on large-scale using Ph3P, with either DIAD or DEAD and a carboxylic acid in THF at either –50 °C or at room temperature”. Hence, several protected mono- and disaccharides, such as 1–4 (Scheme 3) were selectively esterified with simple benzoic acid to give 5–7 and 9, respectively. In
Graphical Abstract
Scheme 1: Left: The Mitsunobu reaction is essentially a nucleophilic substitution of alcohols occurring with ...
Scheme 2: Mechanistic considerations on the Mitsunobu reaction with carbohydrate hemiacetals (depicted in sim...
Scheme 3: Anomeric esterification using the Mitsunobu procedure [29].
Scheme 4: Conversion of allyl glucuronate into various 1-O-esterified allyl glucuronates using anomeric Mitsu...
Scheme 5: Synthesis of anomeric glycosyl esters as substrates for Au-catalyzed glycosylation [40].
Scheme 6: Correlation between pKa value of the employed acids (or alcohol) and the favoured anomeric configur...
Scheme 7: Synthesis of the β-mannosyl phosphates for the synthesis of HBP 43 by anomeric phosphorylation acco...
Scheme 8: Synthesis of phenyl glycosides 44 and 45 from unprotected sugars [24].
Scheme 9: Synthesis of azobenzene mannosides 47 and 48 without protecting group chemistry [46].
Scheme 10: Synthesis of various aryl sialosides using Mitsunobu glycosylation [25].
Scheme 11: Mitsunobu synthesis of different jadomycins [54,55]. BOM: benzyloxymethyl.
Scheme 12: Stereoselectivity in the Mitsunobu synthesis of catechol glycosides in the gluco- and manno-series [56]....
Scheme 13: Formation of a 1,2-cis glycoside 80 assisted by steric hindrance of the β-face of the disaccharide ...
Scheme 14: Stereoselective β-D-mannoside synthesis [60].
Scheme 15: TIPS-assisted synthesis of 1,2-cis arabinofuranosides [63]. TIPS: triisopropylsilyl.
Scheme 16: The Mitsunobu reaction with glycals leads to interesting rearrangement products [69].
Scheme 17: Synthesis of disaccharides using mercury(II) bromide as co-activator in the Mitsunobu reaction [75].
Scheme 18: Synthesis of various fructofuranosides according to Mitsunobu and proposed neighbouring group parti...
Scheme 19: The Mitsunobu reaction allows stereoslective acetalization of dihydroartemisinin [77].
Scheme 20: Synthesis of alkyl thioglycosides by Mitsunobu reaction [81].
Scheme 21: Preparation of iminoglycosylphthalimide 115 from 114 [85].
Scheme 22: Mitsunobu reaction as a key step in the total synthesis of aurantoside G [87].
Scheme 23: Utilization of an N–H acid in the Mitsunobu reaction [88].
Scheme 24: Mitsunobu reaction with 1H-tetrazole [89].
Scheme 25: Formation of a rebeccamycin analogue using the Mitsunobu reaction [101].
Scheme 26: Synthesis of carbohydrates with an alkoxyamine bond [114].
Scheme 27: Synthesis of glycosyl fluorides and glycosyl azides according to Mitsunobu [118,119].
Scheme 28: Anomeric oxidation under Mitsunobu conditions [122].
Recent applications of chiral calixarenes in asymmetric catalysis
- Mustafa Durmaz,
- Erkan Halay and
- Selahattin Bozkurt
Beilstein J. Org. Chem. 2018, 14, 1389–1412, doi:10.3762/bjoc.14.117
- ). The corresponding tetrahydropyridine derivatives 124 were obtained in good to excellent yields but the enantioselectivity remained moderate. Calixarene phosphonic acid (cR,pR)-121 was also tested in the asymmetric ring opening of several cyclic meso epoxides 125 with benzoic acid (Scheme 41). Good
Graphical Abstract
Figure 1: Inherently chiral calix[4]arene-based phase-transfer catalysts.
Scheme 1: Asymmetric alkylations of 3 catalyzed by (±)-1 and (±)-2 under phase-transfer conditions.
Scheme 2: Synthesis of chiral calix[4]arene-based phase-transfer catalyst 7 and structure of O’Donnell’s N-be...
Scheme 3: Asymmetric alkylation of glycine derivative 3 catalyzed by calixarene-based phase-transfer catalyst ...
Figure 2: Calix[4]arene-amides used as phase-transfer catalysts.
Scheme 4: Phase-transfer alkylation of 3 catalyzed by calixarene-triamide 12.
Scheme 5: Synthesis of inherently chiral calix[4]arenes 20a/20b substituted at the lower rim. Reaction condit...
Scheme 6: Asymmetric Henry reaction between 21 and 22 catalyzed by 20a/20b.
Figure 3: Proposed transition state model of asymmetric Henry reaction.
Scheme 7: Synthesis of enantiomerically pure phosphinoferrocenyl-substituted calixarene ligands 27–29.
Scheme 8: Asymmetric coupling reaction of aryl boronates and aryl halides in the presence of calixarene mono ...
Scheme 9: Asymmetric allylic alkylation in the presence of calix[4]arene ligand (S,S)-29.
Figure 4: Structure of inherently chiral oxazoline calix[4]arenes applied in the palladium-catalyzed Tsuji–Tr...
Scheme 10: Asymmetric Tsuji–Trost reaction in the presence of calix[4]arene ligands 36–39.
Figure 5: BINOL-derived calix[4]arene-diphosphite ligands.
Scheme 11: Asymmetric hydrogenation of 41a and 41b catalyzed by in situ-generated catalysts comprised of [Rh(C...
Figure 6: Inherently chiral calix[4]arene 43 containing a diarylmethanol structure.
Scheme 12: Asymmetric Michael addition reaction of 44 with 45 catalyzed by 43.
Figure 7: Calix[4]arene-based chiral primary amine–thiourea catalysts.
Scheme 13: Asymmetric Michael addition of 48 with 49 catalyzed by 47a and 47b.
Scheme 14: Enantioselective Michael addition of 51 to 52 catalyzed by calix[4]arene thioureas.
Scheme 15: Synthesis of calix[4]arene-based tertiary amine–thioureas 54–56.
Scheme 16: Asymmetric Michael addition of 34 and 57 to nitroalkenes 49 catalyzed by 54b.
Scheme 17: Synthesis of p-tert-butylcalix[4]arene bis-squaramide derivative 64.
Scheme 18: Asymmetric Michael addition catalyzed by 64.
Scheme 19: Synthesis of chiral p-tert-butylphenol analogue 68.
Figure 8: Novel prolinamide organocatalysts based on the calix[4]arene scaffold.
Scheme 20: Asymmetric aldol reactions of 72 with 70 and 71 catalyzed by 69b.
Scheme 21: Synthesis of p-tert-butylcalix[4]arene-based chiral organocatalysts 75 and 78 derived from L-prolin...
Scheme 22: Synthesis of upper rim-functionalized calix[4]arene-based L-proline derivative 83.
Scheme 23: Synthesis and proposed structure of Calix-Pro-MN (86).
Figure 9: Calix[4]arene-based L-proline catalysts containing ester, amide and acid units.
Scheme 24: Synthesis of calix[4]arene-based prolinamide 92.
Scheme 25: Calixarene-based catalysts for the aldol reaction of 21 with 70.
Scheme 26: Asymmetric aldol reactions of 72 with cyclic ketones catalyzed by calix[4]arene-based chiral organo...
Figure 10: A proposed structure for catalyst 92 in H2O.
Scheme 27: Synthetic route for organocatalyst 98.
Scheme 28: Asymmetric aldol reactions catalyzed by 99.
Figure 11: Proposed catalytic environment for catalyst 99 in the presence of water.
Scheme 29: Asymmetric aldol reactions between 94 and 72 catalyzed by 55a.
Scheme 30: Enantioselective Biginelli reactions catalyzed by 69f.
Scheme 31: Synthesis of calix[4]arene–(salen) complexes.
Scheme 32: Enantioselective epoxidation of 108 catalyzed by 107a/107b.
Scheme 33: Synthesis of inherently chiral calix[4]arene catalysts 111 and 112.
Scheme 34: Enantioselective MPV reduction.
Scheme 35: Synthesis of chiral calix[4]arene ligands 116a–c.
Scheme 36: Asymmetric MPV reduction with chiral calix[4]arene ligands.
Scheme 37: Chiral AlIII–calixarene complexes bearing distally positioned chiral substituents.
Scheme 38: Asymmetric MPV reduction in the presence of chiral calix[4]arene diphosphites.
Scheme 39: Synthesis of enantiomerically pure inherently chiral calix[4]arene phosphonic acid.
Scheme 40: Asymmetric aza-Diels–Alder reactions catalyzed by (cR,pR)-121.
Scheme 41: Asymmetric ring opening of epoxides catalyzed by (cR,pR)-121.
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
- -iodobenzoic acid is formed as a quantitative waste product, thus lowering the atom efficiency of these transformations. An atom-economical application of benziodoxolones 36 would involve the utilization of the nucleophilic properties of the released benzoic acid 37, after the initial electrophilic group
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.
Selective carboxylation of reactive benzylic C–H bonds by a hypervalent iodine(III)/inorganic bromide oxidation system
- Toshifumi Dohi,
- Shohei Ueda,
- Kosuke Iwasaki,
- Yusuke Tsunoda,
- Koji Morimoto and
- Yasuyuki Kita
Beilstein J. Org. Chem. 2018, 14, 1087–1094, doi:10.3762/bjoc.14.94
- acids, such as propionic acid, cyclohexyl carboxylic acid, pivalic acid, and benzoic acid, were also possible by simply replacing PIDA with iodosobenzene (Scheme 3). Here, the addition of 3 Å molecular sieves was essential for removing water derived from the iodosobenzene and to suppress the benzylic
Graphical Abstract
Scheme 1: Hypervalent iodine(III)-induced benzylic C–H functionalization for oxidative coupling with carboxyl...
Scheme 2: Radical reactivities of the I(III)–Br bond generated from PIDA.
Scheme 3: Benzylic C–H carboxylations by the iodosobenzene/NaBr system.
Scheme 4: Outline of the proposed reaction mechanism for the PIDA/NaBr system.
Scheme 5: Reaction of benzyl bromide 2h’ under radical C–H acetoxylation conditions.
Preparation, structure, and reactivity of bicyclic benziodazole: a new hypervalent iodine heterocycle
- Akira Yoshimura,
- Michael T. Shea,
- Cody L. Makitalo,
- Melissa E. Jarvi,
- Gregory T. Rohde,
- Akio Saito,
- Mekhman S. Yusubov and
- Viktor V. Zhdankin
Beilstein J. Org. Chem. 2018, 14, 1016–1020, doi:10.3762/bjoc.14.87
- and N,N-dimethyl-4-aminopyridine (DMAP) in chloroform solution under reflux conditions afforded the desired product 11a in good yield. As expected, the reactions of benzoic acid (9b) with benzyl alcohol (10a) or 1-pentanol (10b) under the same conditions gave the corresponding esters 11b or 11c in
Graphical Abstract
Scheme 1: Representative examples of benziodoxoles and benziodazoles.
Scheme 2: Preparation of bicyclic benziodazole 7a.
Figure 1: X-ray crystal structure of compound 7a. Ellipsoids are drawn to the 50% probability level. Selected...
Scheme 3: Benziodadiazole 7a mediated oxidatively assisted esterification and amidation reactions.
Anodic oxidation of bisamides from diaminoalkanes by constant current electrolysis
- Tatiana Golub and
- James Y. Becker
Beilstein J. Org. Chem. 2018, 14, 861–868, doi:10.3762/bjoc.14.72
- comparison to the above results, oxidation of II-3 on a Pt anode (Table 2, entries 3 and 4) affords similar products but with less selectivity because of the formation of an additional fragmentation product, benzoic acid (II-3e) in 10–20% yield. Other anodes were tested as well (Table 2, entries 5–7) at an
- undergoes methoxylation in methanol, as described in Scheme 11. Plausible mechanisms for the formation of various fragmentation products are described in Scheme 12. Actually whenever benzoic acid or methyl benzoate were formed (top of Scheme 12), the corresponding aldehyde from the other part of the
Graphical Abstract
Scheme 1: Anodic oxidation of amides.
Scheme 2: Anodic oxidation of an amide in the presence of alkene.
Scheme 3: Intramolecular cyclization via anodic oxidation of an eneamide.
Scheme 4: Anodic bond cleavages in amides of type Ph2CHCONHAr.
Scheme 5: Type of products obtained (n = 0, 1, 2).
Scheme 6: Synthesized cyclic N-acyl and N-sulfonyl piperidines for electrolysis.
Scheme 7: Type of bisamides (derived from diamines) studied (n = 2, 3, 4).
Scheme 8: Type of products obtained from anodic oxidation of II-3.
Scheme 9: Anodic splitting of C–C bond in bisamides in the presence of LiClO4 electrolyte.
Scheme 10: Anodic splitting of C–C bond in bisamides in the presence of Et4NBF4 electrolyte.
Scheme 11: A suggested mechanism for anodic methoxylation of amides.
Scheme 12: Mechanisms of formation of fragmentation products.
Synthesis and stability of strongly acidic benzamide derivatives
- Frederik Diness,
- Niels J. Bjerrum and
- Mikael Begtrup
Beilstein J. Org. Chem. 2018, 14, 523–530, doi:10.3762/bjoc.14.38
- stability under acidic and basic conditions are also reported. Keywords: benzoic acid; cross-coupling; hydrolysis; SNAr; trifluoromethanesulfonamide; Introduction Very strong organic acids are interesting as catalysts for chemical reactions [1][2] and for facilitation of proton conduction [3]. In order to
- ) or trifluoroacetic acid (3) are not readily modified, and changing substituents on these acids will heavily impact their pKa value (Figure 1). In contrast, halogenated benzoic acid derivatives are easily functionalized through cross-coupling [4][5] or nucleophilic aromatic substitution reactions
- (SNAr) [6][7]. Benzoic acids (e.g., 2) are relatively weak acids, even with highly electron-withdrawing substituents on the aromatic core [8]. Very strong benzoic acid derivatives (e.g., 4 and 6) have been synthesized by replacing one or both of the oxygens of the carboxylate group with the
Graphical Abstract
Figure 1: Acid strength (pKa) of various organic acids in acetonitrile or water (nr = not reported) [12-14].
Figure 2: Examples of functional molecules containing an N-triflylbenzamide.
Scheme 1: Synthesis of the strongly acidic benzamide derivatives.
Scheme 2: SNAr reactions of fluoro-substituted benzamide derivatives.
Scheme 3: Cross-coupling reactions of N-triflylbenzoic acid derivatives.
Scheme 4: Hydrolysis rates of the 4-bromobenzoic acid derivatives.
Figure 3: Content (percent) of super acids (0.5 mg/mL) over time (hours) in H3PO4/H2O/MeOH 17:3:20 at 50 °C.
5-Aminopyrazole as precursor in design and synthesis of fused pyrazoloazines
- Ranjana Aggarwal and
- Suresh Kumar
Beilstein J. Org. Chem. 2018, 14, 203–242, doi:10.3762/bjoc.14.15
- products in small amounts namely 3(5)-methyl-5(3)-phenyl-1H-pyrazole (121) obtained by CN bond cleavage and benzoic acid (122) was also observed (Scheme 33). The structure of the regioisomer was established unequivocally by performing 1H,13C-HMQC, 1H,13C- and 1H,15N-HMBC experiments. Aqueous mediated
Graphical Abstract
Figure 1: Selected examples of drugs with fused pyrazole rings.
Figure 2: Typical structures of some fused pyrazoloazines from 5-aminopyrazoles.
Scheme 1: Regiospecific synthesis of 4 and 6-trifluoromethyl-1H-pyrazolo[3,4-b]pyridines.
Scheme 2: Synthesis of pyrazolo[3,4-b]pyridine-6-carboxylates.
Scheme 3: Synthesis of 1,4,6-triaryl-1H-pyrazolo[3,4-b]pyridines with ionic liquid .
Scheme 4: Synthesis of coumarin-based isomeric tetracyclic pyrazolo[3,4-b]pyridines.
Scheme 5: Synthesis of 6-substituted pyrazolo[3,4-b]pyridines under Heck conditions.
Scheme 6: Microwave-assisted palladium-catalyzed synthesis of pyrazolo[3,4-b]pyridines.
Scheme 7: Acid-catalyzed synthesis of pyrazolo[3,4-b]pyridines via enaminones.
Scheme 8: Synthesis of pyrazolo[3,4-b]pyridines via aza-Diels–Alder reaction.
Scheme 9: Synthesis of macrocyclane fused pyrazolo[3,4-b]pyridine derivatives.
Scheme 10: Three-component synthesis of 4,7-dihydro-1H-pyrazolo[3,4-b]pyridine derivatives.
Scheme 11: Ultrasonicated synthesis of spiro[indoline-3,4'-pyrazolo[3,4-b]pyridine]-2,6'(1'H)-diones.
Scheme 12: Synthesis of spiro[indoline-3,4'-pyrazolo[3,4-b]pyridine] derivatives under conventional heating co...
Scheme 13: Nanoparticle-catalyzed synthesis of pyrazolo[3,4-b]pyridine-spiroindolinones.
Scheme 14: Microwave-assisted multicomponent synthesis of spiropyrazolo[3,4-b]pyridines.
Scheme 15: Unexpected synthesis of naphthoic acid-substituted pyrazolo[3,4-b]pyridines.
Scheme 16: Multicomponent synthesis of variously substituted pyrazolo[3,4-b]pyridine derivatives.
Scheme 17: Three-component synthesis of 4,7-dihydropyrazolo[3,4-b]pyridines and pyrazolo[3,4-b]pyridines.
Scheme 18: Synthesis of pyrazolo[3,4-b]pyridine-5-spirocycloalkanediones.
Scheme 19: Ultrasound-mediated three-component synthesis of pyrazolo[3,4-b]pyridines.
Scheme 20: Multicomponent synthesis of 4-aryl-3-methyl-1-phenyl-4,6,8,9-tetrahydropyrazolo [3,4-b]thiopyrano[4...
Scheme 21: Synthesis of 2,3-dihydrochromeno[4,3-d]pyrazolo[3,4-b]pyridine-1,6-diones.
Scheme 22: FeCl3-catalyzed synthesis of o-hydroxyphenylpyrazolo[3,4-b]pyridine derivatives.
Scheme 23: Ionic liquid-mediated synthesis of pyrazolo[3,4-b]pyridines.
Scheme 24: Microwave-assisted synthesis of pyrazolo[3,4-b]pyridines.
Scheme 25: Multicomponent synthesis of pyrazolo[3,4-b]pyridine-5-carbonitriles.
Scheme 26: Unusual domino synthesis of 4,7-dihydropyrazolo[3,4-b]pyridine-5-nitriles.
Scheme 27: Synthesis of 4,5,6,7-tetrahydro-4H-pyrazolo[3,4-b]pyridines under conventional heating and ultrasou...
Scheme 28: L-Proline-catalyzed synthesis of of pyrazolo[3,4-b]pyridine.
Scheme 29: Microwave-assisted synthesis of 5-aminoarylpyrazolo[3,4-b]pyridines.
Scheme 30: Microwave-assisted multi-component synthesis of pyrazolo[3,4-e]indolizines.
Scheme 31: Synthesis of fluoropropynyl and fluoroalkyl substituted pyrazolo[1,5-a]pyrimidine.
Scheme 32: Acid-catalyzed synthesis of pyrazolo[1,5-a]pyrimidine derivatives.
Scheme 33: Chemoselective and regiospecific synthesis of 2-(3-methylpyrazol-1’-yl)-5-methylpyrazolo[1,5-a]pyri...
Scheme 34: Regioselective synthesis of 7-trifluoromethylpyrazolo[1,5-a]pyrimidines.
Scheme 35: Microwave-assisted synthesis of 7-trifluoromethylpyrazolo[1,5-a]pyrimidine carboxylates.
Scheme 36: Microwave and ultrasound-assisted synthesis of 7-trifluoromethylpyrazolo[1,5-a]pyrimidines.
Scheme 37: Base-catalyzed unprecedented synthesis of pyrazolo[1,5-a]pyrimidines via C–C bond cleavage.
Scheme 38: Synthesis of aminobenzothiazole/piperazine linked pyrazolo[1,5-a]pyrimidines.
Scheme 39: Synthesis of aminoalkylpyrazolo[1,5-a]pyrimidine-7-amines.
Scheme 40: Synthesis of pyrazolo[1,5-a]pyrimidines from condensation of 5-aminopyrazole 126 and ethyl acetoace...
Scheme 41: Synthesis of 7-aminopyrazolo[1,5-a]pyrimidines.
Scheme 42: Unexpected synthesis of 7-aminopyrazolo[1,5-a]pyrimidines under solvent free and solvent-mediated c...
Scheme 43: Synthesis of N-(4-aminophenyl)-7-aryloxypyrazolo[1,5-a]pyrimidin-5-amines.
Scheme 44: Base-catalyzed synthesis of 5,7-diarylpyrazolo[1,5-a]pyrimidines.
Scheme 45: Synthesis of 6,7-dihydropyrazolo[1,5-a]pyrimidines in PEG-400.
Scheme 46: Synthesis of 7-heteroarylpyrazolo[1,5-a]pyrimidine-3-carboxamides.
Scheme 47: Synthesis of 7-heteroarylpyrazolo[1,5-a]pyrimidine derivatives under conventional heating and micro...
Scheme 48: Synthesis of N-aroylpyrazolo[1,5-a]pyrimidine-5-amines.
Scheme 49: Regioselective synthesis of ethyl pyrazolo[1,5-a]pyrimidine-7-carboxylate.
Scheme 50: Sodium methoxide-catalyzed synthesis of 3-cyano-6,7-diarylpyrazolo[1,5-a]pyrimidines.
Scheme 51: Synthesis of various pyrazolo[3,4-d]pyrimidine derivatives.
Scheme 52: Synthesis of hydrazinopyrazolo[3,4-d]pyrimidine derivatives.
Scheme 53: Synthesis of N-arylidinepyrazolo[3,4-d]pyrimidin-5-amines.
Scheme 54: Synthesis of pyrazolo[3,4-d]pyrimidinyl-4-amines.
Scheme 55: Iodine-catalyzed synthesis of pyrazolo[3,4-d]pyrimidinones.
Scheme 56: Synthesis of ethyl 6-amino-2H-pyrazolo[3,4-d]pyrimidine-4-carboxylate.
Scheme 57: Synthesis of 4-substituted-(3,6-dihydropyran-4-yl)-1H-pyrazolo[3,4-d]pyrimidines.
Scheme 58: Synthesis of 1-(2,4-dichlorophenyl)pyrazolo[3,4-d]pyrimidin-4-yl carboxamides.
Scheme 59: Synthesis of 5-(1,3,4-thidiazol-2-yl)pyrazolo[3,4-d]pyrimidine.
Scheme 60: One pot POCl3-catalyzed synthesis of 1-arylpyrazolo[3,4-d]pyrimidin-4-ones.
Scheme 61: Synthesis of 4-amino-N1,C3-dialkylpyrazolo[3,4-d]pyrimidines under Suzuki conditions.
Scheme 62: Microwave-assisted synthesis of pyrazolo[3,4-b]pyrazines.
Scheme 63: Synthesis and derivatization of pyrazolo[3,4-b]pyrazine-5-carbonitriles.
Scheme 64: Synthesis of 2-thioxo-pyrazolo[1,5-a][1,3,5]triazin-4-ones.
Scheme 65: Synthesis of 2,3-dihydropyrazolo[1,5-a][1,3,5]triazin-4(1H)-one.
Scheme 66: Synthesis of pyrazolo[1,5-a][1,3,5]triazine-8-carboxylic acid ethyl ester.
Scheme 67: Microwave-assisted synthesis of 4,7-dihetarylpyrazolo[1,5-a][1,3,5]triazines.
Scheme 68: Alternative synthetic route to 4,7-diheteroarylpyrazolo[1,5-a][1,3,5]triazines.
Scheme 69: Synthesis of 4-aryl-2-ethylthio-7-methylpyrazolo[1,5-a][1,3,5]triazines.
Scheme 70: Microwave-assisted synthesis of 4-aminopyrazolo[1,5-a][1,3,5]triazine.
Scheme 71: Synthesis of pyrazolo[3,4-d][1,2,3]triazines from pyrazol-5-yl diazonium salts.
Scheme 72: Synthesis of 2,5-dihydropyrazolo[3,4-e][1,2,4]triazines.
Scheme 73: Synthesis of pyrazolo[5,1-c][1,2,4]triazines via diazopyrazolylenaminones.
Scheme 74: Synthesis of pyrazolo[5,1-c][1,2,4]triazines in presence of sodium acetate.
Scheme 75: Synthesis of various 7-diazopyrazolo[5,1-c][1,2,4]triazine derivatives.
Scheme 76: One pot synthesis of pyrazolo[5,1-c][1,2,4]triazines.
Scheme 77: Synthesis of 4-amino-3,7,8-trinitropyrazolo-[5,1-c][1,2,4]triazines.
Scheme 78: Synthesis of tricyclic pyrazolo[5,1-c][1,2,4]triazines by azocoupling reaction.
Photocatalytic formation of carbon–sulfur bonds
- Alexander Wimmer and
- Burkhard König
Beilstein J. Org. Chem. 2018, 14, 54–83, doi:10.3762/bjoc.14.4
- metal-free method for the synthesis of benzothiophenes via a photocatalyzed tandem addition/cyclization reaction (Scheme 11) [41]. Aryl thiols were coupled with dimethyl acetylenedicarboxylate, applying 9-mesityl-10-methylacridinium perchlorate (Acr+-Mes ClO4−) as organic photocatalyst and benzoic acid
Graphical Abstract
Scheme 1: General overview over the sulfur-based substrates and reactive intermediates that are discussed in ...
Scheme 2: Photoredox-catalyzed radical thiol–ene reaction, applying [Ru(bpz)3](PF6)2 as photocatalyst.
Scheme 3: Photoredox-catalyzed thiol–ene reaction of aliphatic thiols with alkenes enabled by aniline derivat...
Scheme 4: Photoredox-catalyzed radical thiol–ene reaction for the postfunctionalization of polymers (a) and n...
Scheme 5: Photoredox-catalyzed thiol–ene reaction enabled by bromotrichloromethane as redox additive.
Scheme 6: Photoredox-catalyzed preparation of β-ketosulfoxides with Eosin Y as organic dye as photoredox cata...
Scheme 7: Greaney’s photocatalytic radical thiol–ene reaction, applying TiO2 nanoparticles as photocatalyst.
Scheme 8: Fadeyi’s photocatalytic radical thiol–ene reaction, applying Bi2O3 as photocatalyst.
Scheme 9: Ananikov’s photocatalytic radical thiol-yne reaction, applying Eosin Y as photocatalyst.
Scheme 10: Organocatalytic visible-light photoinitiated thiol–ene coupling, applying phenylglyoxylic acid as o...
Scheme 11: Xia’s photoredox-catalyzed synthesis of 2,3-disubstituted benzothiophenes, applying 9-mesityl-10-me...
Scheme 12: Wang’s metal-free photoredox-catalyzed radical thiol–ene reaction, applying 9-mesityl-10-methylacri...
Scheme 13: Visible-light benzophenone-catalyzed metal- and oxidant-free radical thiol–ene reaction.
Scheme 14: Visible-light catalyzed C-3 sulfenylation of indole derivatives using Rose Bengal as organic dye.
Scheme 15: Photocatalyzed radical thiol–ene reaction and subsequent aerobic sulfide-oxidation with Rose Bengal...
Scheme 16: Photoredox-catalyzed synthesis of diaryl sulfides.
Scheme 17: Photocatalytic cross-coupling of aryl thiols with aryl diazonium salts, using Eosin Y as photoredox...
Scheme 18: Photocatalyzed cross-coupling of aryl diazonium salts with cysteines in batch and in a microphotore...
Scheme 19: Fu’s [Ir]-catalyzed photoredox arylation of aryl thiols with aryl halides.
Scheme 20: Fu’s photoredox-catalyzed difluoromethylation of aryl thiols.
Scheme 21: C–S cross-coupling of thiols with aryl iodides via [Ir]-photoredox and [Ni]-dual-catalysis.
Scheme 22: C–S cross-coupling of thiols with aryl bromides, applying 3,7-bis-(biphenyl-4-yl)-10-(1-naphthyl)ph...
Scheme 23: Collin’s photochemical dual-catalytic cross-coupling of thiols with bromoalkynes.
Scheme 24: Visible-light-promoted C–S cross-coupling via intermolecular electron donor–acceptor complex format...
Scheme 25: Li’s visible-light photoredox-catalyzed thiocyanation of indole derivatives with Rose Bengal as pho...
Scheme 26: Hajra’s visible-light photoredox-catalyzed thiocyanation of imidazoheterocycles with Eosin Y as pho...
Scheme 27: Wang’s photoredox-catalyzed thiocyanation reaction of indoles, applying heterogeneous TiO2/MoS2 nan...
Scheme 28: Yadav’s photoredox-catalyzed α-C(sp3)–H thiocyanation reaction for tertiary amines, applying Eosin ...
Scheme 29: Yadav’s photoredox-catalyzed synthesis of 5-aryl-2-imino-1,3-oxathiolanes.
Scheme 30: Yadav’s photoredox-catalyzed synthesis of 1,3-oxathiolane-2-thiones.
Scheme 31: Li’s photoredox catalysis for the preparation of 2-substituted benzothiazoles, applying [Ru(bpy)3](...
Scheme 32: Lei’s external oxidant-free synthesis of 2-substituted benzothiazoles by merging photoredox and tra...
Scheme 33: Metal-free photocatalyzed synthesis of 2-aminobenzothiazoles, applying Eosin Y as photocatalyst.
Scheme 34: Metal-free photocatalyzed synthesis of 1,3,4-thiadiazoles, using Eosin Y as photocatalyst.
Scheme 35: Visible-light photoredox-catalyzed preparation of benzothiophenes with Eosin Y.
Scheme 36: Visible-light-induced KOH/DMSO superbase-promoted preparation of benzothiophenes.
Scheme 37: Jacobi von Wangelin’s photocatalytic approach for the synthesis of aryl sulfides, applying Eosin Y ...
Scheme 38: Visible-light photosensitized α-C(sp3)–H thiolation of aliphatic ethers.
Scheme 39: Visible-light photocatalyzed cross-coupling of alkyl and aryl thiosulfates with aryl diazonium salt...
Scheme 40: Visible-light photocatalyzed, controllable sulfenylation and sulfoxidation with organic thiosulfate...
Scheme 41: Rastogi’s photoredox-catalyzed methylsulfoxidation of aryl diazonium salts, using [Ru(bpy)3]Cl2 as ...
Scheme 42: a) Visible-light metal-free Eosin Y-catalyzed procedure for the preparation of vinyl sulfones from ...
Scheme 43: Visible-light photocatalyzed cross-coupling of sodium sulfinates with secondary enamides.
Scheme 44: Wang’s photocatalyzed oxidative cyclization of phenyl propiolates with sulfinic acids, applying Eos...
Scheme 45: Lei’s sacrificial oxidant-free synthesis of allyl sulfones by merging photoredox and transition met...
Scheme 46: Photocatalyzed Markovnikov-selective radical/radical cross-coupling of aryl sulfinic acids and term...
Scheme 47: Visible-light Eosin Y induced cross-coupling of aryl sulfinic acids and styrene derivatives, afford...
Scheme 48: Photoredox-catalyzed bicyclization of 1,7-enynes with sulfinic acids, applying Eosin Y as photocata...
Scheme 49: Visible-light-accelerated C–H-sulfinylation of arenes and heteroarenes.
Scheme 50: Visible-light photoredox-catalyzed β-selenosulfonylation of electron-rich olefins, applying [Ru(bpy)...
Scheme 51: Photocatalyzed preparation of β-chlorosulfones from the respective olefins and p-toluenesulfonyl ch...
Scheme 52: a) Photocatalyzed preparation of β-amidovinyl sulfones from sulfonyl chlorides. b) Preparation of β...
Scheme 53: Visible-light photocatalyzed sulfonylation of aliphatic tertiary amines, applying [Ru(bpy)3](PF6)2 ...
Scheme 54: Reiser’s visible-light photoredox-catalyzed preparation of β-hydroxysulfones from sulfonyl chloride...
Scheme 55: a) Sun’s visible-light-catalyzed approach for the preparation of isoquinolinonediones, applying [fac...
Scheme 56: Visible-light photocatalyzed sulfonylation/cyclization of vinyl azides, applying [Ru(bpy)3]Cl2 as p...
Scheme 57: Visible-light photocatalyzed procedure for the formation of β-ketosulfones from aryl sulfonyl chlor...
Scheme 58: Zheng’s method for the sulfenylation of indole derivatives, applying sulfonyl chlorides via visible...
Scheme 59: Cai’s visible-light induced synthesis of β-ketosulfones from sulfonyl hydrazines and alkynes.
Scheme 60: Photoredox-catalyzed approach for the preparation of vinyl sulfones from sulfonyl hydrazines and ci...
Scheme 61: Jacobi von Wangelin’s visible-light photocatalyzed chlorosulfonylation of anilines.
Scheme 62: Three-component photoredox-catalyzed synthesis of N-amino sulfonamides, applying PDI as organic dye....
Scheme 63: Visible-light induced preparation of complex sulfones from oximes, silyl enol ethers and SO2.
Dialkyl dicyanofumarates and dicyanomaleates as versatile building blocks for synthetic organic chemistry and mechanistic studies
- Grzegorz Mlostoń and
- Heinz Heimgartner
Beilstein J. Org. Chem. 2017, 13, 2235–2251, doi:10.3762/bjoc.13.221
- [64]. The yields of the products are in the range of 57–72%. A different type of heterocyclization was reported in the reactions of carbohydrazides 67 derived from benzoic acid and some hetarylcarboxylic acids with E-1a [65][66]. In these cases, the formation of mixtures of two products is described
Graphical Abstract
Figure 1: Dialkyl dicyanofumarates E-1 and dicyanomaleates Z-1.
Scheme 1: Methods for the synthesis of dialkyl dicyanofumarates E-1 from alkyl cyanoacetates 2.
Scheme 2: Methods for the synthesis of dialkyl dicyanofumarates E-1 from alkyl bromoacetates 3.
Scheme 3: Reaction of dimethyl dicyanofumarate (E-1b) with dimethoxycarbene [(MeO)2C:] generated in situ from...
Scheme 4: Cyclopropanation of diethyl dicyanofumarate (E-1a) through reaction with the thiophene derived sulf...
Scheme 5: Cyclopropanation of dimethyl dicyanofumarate (E-1b) through a stepwise reaction with the in situ ge...
Scheme 6: The [2 + 2]-cycloadditions of dimethyl dicyanofumarate (E-1b) with electron-rich ethylenes 20 and 22...
Scheme 7: The [2 + 2]-cycloaddition of isomeric dimethyl dicyanofumarate (E-1b) and dicyanomaleate (Z-1b) wit...
Scheme 8: Non-concerted [2 + 2]-cycloaddition between E-1b and bicyclo[2.1.0]pentene (27).
Scheme 9: Stepwise [3 + 2]-cycloadditions of some thiocarbonyl S-methanides with dialkyl dicyanofumarates E-1...
Scheme 10: Stepwise [3 + 2]-cycloadditions of dimethyl dicyanofumarate (E-1b) and dimethyl dicyanomaleate (Z-1b...
Scheme 11: [3 + 2]-Cycloaddition of diazomethane with dimethyl dicyanofumarate (E-1b) leading to 1H-pyrazole d...
Scheme 12: Reversible Diels–Alder reaction of fulvenes 36 with diethyl dicyanofumarate (E-1a).
Scheme 13: [4 + 2]-Cycloaddition of 9,10-dimethylanthracene (39b) and E-1a.
Scheme 14: Stepwise [4 + 2]-cycloaddition of dimethyl dicyanofumarate (E-1b) with electron-rich 1,1-dimethoxy-...
Scheme 15: Formal [4 + 2]-cycloaddition of 3,4-di(α-styryl)furan (47) with dimethyl dicyanofumarate (E-1b).
Scheme 16: Acid-catalyzed Michael addition of enolizable ketones of type 49 to E-1.
Scheme 17: Reaction of diethyl dicyanofumarate (E-1a) with ammonia NH3.
Scheme 18: Reaction of dialkyl dicyanofumarates E-1 with primary and secondary amines.
Scheme 19: Reaction of dialkyl dicyanofumarates E-1 with 1-azabicyclo[1.1.0]butanes 55.
Scheme 20: Formation of pyrazole derivatives in the reaction of hydrazines with E-1.
Scheme 21: Formation of 5-aminopyrazole-3,4-dicarboxylate 65 via heterocyclization reactions.
Scheme 22: Reactions of aryl- and hetarylcarbohydrazides 67 with E-1a.
Scheme 23: Multistep reaction leading to perhydroquinoxaline derivative 73.
Scheme 24: Synthesis of ethyl 7-aminopteridin-6-carboxylates 75 via a domino reaction.
Scheme 25: Synthesis of morhpolin-2-ones 80 from E-1 and β-aminoalcohols 78 through an initial aza-Michael add...
Scheme 26: Reaction of 3-amino-5-arylpyrazoles 81 with dialkyl dicyanofumarates E-1 via competitive nucleophil...
Scheme 27: Heterocyclization reaction of thiosemicarbazone 86 with E-1a.
Scheme 28: Formation of diethyl 4-cyano-5-oxotetrahydro-4H-chromene-3,4-dicarboxylate (90) from E-1a via heter...
Scheme 29: Reaction of dialkyl dicyanofumarates E-1 with cysteamine (92).
Scheme 30: Formation of disulfides through reaction of thiols with E-1a.
Scheme 31: Formation of CT salts of E-1 with Mn2+ and Cr2+ metallocenes through one-electron transfer.
Scheme 32: Oxidation of diethyl dicyanofumarate (E-1a) with H2O2 to give oxirane 101.
Scheme 33: The aziridination of E-1b through nitrene addition.
Synthesis of benzannelated sultams by intramolecular Pd-catalyzed arylation of tertiary sulfonamides
- Valentin A. Rassadin,
- Mirko Scholz,
- Anastasiia A. Klochkova,
- Armin de Meijere and
- Victor V. Sokolov
Beilstein J. Org. Chem. 2017, 13, 1932–1939, doi:10.3762/bjoc.13.187
- distilled dioxane, the sultams 10d and 10e were isolated in 78 and 86% yield, respectively. However, when commercial dioxane was used, both sulfonamide 8d as well as 8e gave the same product, namely the benzoic acid derivative 10h in 65 and 71% yield, respectively. Apparently, the commercial dioxane
Graphical Abstract
Scheme 1: A previous and a new approach to arene-annelated sultams.
Scheme 2: Pd-catalyzed cyclization of (2-iodophenyl)sulfonamides 3 and 5.
Scheme 3: Preparation of 4-methoxybenzyl-protected methyl 2-(N-o-iodoarylsulfamoyl)acetates 8. Reagents and c...
Scheme 4: Synthesis of arene-annelated sultams 10 by Pd-catalyzed intramolecular arylation of a C–H acidic me...
Figure 1: Structure of methyl 5-chloro-1-(4-methoxybenzyl)-1,3-dihydrobenzo[c]isothiazole-3-carboxylate-2,2-d...
Scheme 5: Palladium-catalyzed transformation of N-(2-iodophenyl)-N-(4-methoxybenzyl-benzylsulfonamide 12. Ar ...
Scheme 6: Palladium-catalyzed intramolecular arylation to yield a benzannelated six-membered sultam 21. Ar = ...
Scheme 7: An attempted and a successful removal of the PMB group from the sultam 10a.
Figure 2: Structure of methyl 1-(4-methoxybenzyl)-3-(nitrooxy)-1,3-dihydrobenzo[c]isothiazole-3-carboxylate-2...
