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Search for "nucleophilic addition" in Full Text gives 258 result(s) in Beilstein Journal of Organic Chemistry. Showing first 200.
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
- -2-carbaldehyde on the other hand resulted in appreciable yields under similar reaction conditions. The authors have successfully constructed a big library of 28 compounds with varying structure. In 2013, Gao et al. have exploited the TM-catalyzed nucleophilic addition reactions of haloalkynes 5
- single-electron transfer (SET) with CuI followed by hydride abstraction/intramolecular nucleophilic addition and loss of a proton forming the desired compound 49 (Scheme 19). Cu(I)-catalyzed intramolecular oxidative C–H amidation of N-pyridylenaminones 61 for the synthesis of imidazo[1,2-a]pyridine
- towards differently substituted reacting compounds. Acetophenones bearing EWGs reacted faster than those with EDGs as these groups might be unfavorable for the nucleophilic addition step during the reaction (Figure 3). The advantageous point of the protocol involves the recovery and reusability of the
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.
A novel three-component reaction between isocyanides, alcohols or thiols and elemental sulfur: a mild, catalyst-free approach towards O-thiocarbamates and dithiocarbamates
- András György Németh,
- György Miklós Keserű and
- Péter Ábrányi-Balogh
Beilstein J. Org. Chem. 2019, 15, 1523–1533, doi:10.3762/bjoc.15.155
- elemental sulfur and NaH generates a polysulfide anion that is able to attack the carbenoid carbon atom of isocyanide 1a yielding the isothiocyanate intermediate 8. Then, the present nucleophile (NuH, alcohol or thiol) undergoes a nucleophilic addition on 8 providing thiocarbamate 3a. Conclusion In summary
Graphical Abstract
Scheme 1: Synthetic routes to O-thiocarbamates and dithiocarbamates.
Scheme 2: Substrate scope of isocyanides. aReaction conditions: 1 (1 mmol), S8 (2 mmol), 2a (2mmol), NaH (2 m...
Scheme 3: Substrate scope of alcohols. Reaction conditions: 1a (1 mmol), S8 (2 mmol), 2 (2mmol), NaH (2 mmol)...
Scheme 4: Substrate scope of thiols. Reaction conditions: 1a (1 mmol), S8 (1.2 mmol), 4 (2 mmol), NaOH (2 mmo...
Scheme 5: Scaled-up synthesis for 3a.
Scheme 6: Multicomponent domino synthesis of quinazolinone 7.
Scheme 7: Control experiments.
Scheme 8: Proposed mechanism.
Efficient synthesis of pyrazolopyridines containing a chromane backbone through domino reaction
- Razieh Navari,
- Saeed Balalaie,
- Saber Mehrparvar,
- Fatemeh Darvish,
- Frank Rominger,
- Fatima Hamdan and
- Sattar Mirzaie
Beilstein J. Org. Chem. 2019, 15, 874–880, doi:10.3762/bjoc.15.85
- hexamethylenedisalazane is necessary. However, in this approach, the nucleophilic addition on the nitrile group and the cyclization was achieved without the addition of a catalyst [44]. This reaction possesses a highly atom economical character and requires only triethylamine (40 mol %) as a base in EtOH and provides
Graphical Abstract
Figure 1: Selected examples of bioactive molecules based on the pyrazolopyridine framework.
Scheme 1: Synthesis of pyrazolopyridines containing chromone 4a–m through a multicomponent reaction.
Figure 2: ORTEP Structure of compound 4a and intermolecular hydrogen bonding; the ellipsoid probability level...
Figure 3: Structures of synthesized pyrazolopyridines 4a–m. Reaction conditions: 3-formylchromone derivatives...
Scheme 2: The proposed mechanism for the synthesis of pyrazolopyridines derivatives 4a–m and 5a–d.
Figure 4: Structures of synthesized compounds 5a–d.
Synthesis of a novel category of pseudo-peptides using an Ugi three-component reaction of levulinic acid as bifunctional substrate, amines, and amino acid-based isocyanides
- Maryam Khalesi,
- Azim Ziyaei Halimehjani and
- Jürgen Martens
Beilstein J. Org. Chem. 2019, 15, 852–857, doi:10.3762/bjoc.15.82
- component that leads to the formation of an imine intermediate A. The formed Schiff base is in equilibrium with its iminium cation B as a result of an intramolecular proton exchange with the carboxylic acid moiety which activates the iminium ion for the nucleophilic addition of isocyanide. Consequently, the
- electrophilic centre of the iminium ion in B is subjected to a nucleophilic attack of the isocyanide to furnish the intermediate C. Then, a second nucleophilic addition takes place at this nitrilium intermediate C with an intramolecular nucleophilic addition of the carboxylate anion. The final step is an acyl
Graphical Abstract
Scheme 1: Synthesis of amino acid-based isocyanides starting from α-amino acids.
Scheme 2: Synthesis of pseudo-peptides using levulinic acid, isocyanide esters and amines.
Figure 1: Synthesis of functionalized 5-membered lactams using Ugi reaction. aIsolated yield for mixture of d...
Scheme 3: Proposed mechanism for Ugi-4C-3CR.
Figure 2: ORTEP representation of compound (R*,S*)-4a with thermal ellipsoids at 50% probability. Opposite en...
Sigmatropic rearrangements of cyclopropenylcarbinol derivatives. Access to diversely substituted alkylidenecyclopropanes
- Guillaume Ernouf,
- Jean-Louis Brayer,
- Christophe Meyer and
- Janine Cossy
Beilstein J. Org. Chem. 2019, 15, 333–350, doi:10.3762/bjoc.15.29
- formation of the gem-dichloro-α-lactam intermediate 17f which would undergo ring opening by nucleophilic addition of pyrrolidine followed by hydrolysis of the resulting α,α-dichloro-α-aminoacetamide 18f (Scheme 12). To access aminocyclopropanes, the hydrogenation of (arylmethylene)cyclopropane 13f was
Graphical Abstract
Scheme 1: Representative strategies for the formation of alkylidenecyclopropanes from cyclopropenes and scope...
Scheme 2: [2,3]-Sigmatropic rearrangement of phosphinites 2a–h.
Scheme 3: [2,3]-Sigmatropic rearrangement of a phosphinite derived from enantioenriched cyclopropenylcarbinol...
Scheme 4: Selective reduction of phosphine oxide (E)-3f.
Scheme 5: Attempted thermal [2,3]-sigmatropic rearrangement of phosphinite 6a.
Scheme 6: Computed activation barriers and free enthalpies.
Scheme 7: [2,3]-Sigmatropic rearrangement of phosphinites 6a–j.
Scheme 8: Proposed mechanism for the Lewis base-catalyzed rearrangement of phosphinites 6.
Scheme 9: [3,3]-Sigmatropic rearrangement of tertiary cyclopropenylcarbinyl acetates 10a–c.
Scheme 10: [3,3]-Sigmatropic rearrangement of secondary cyclopropenylcarbinyl esters 10d–h.
Scheme 11: [3,3]-Sigmatropic rearrangement of trichoroacetimidates 12a–i.
Scheme 12: Reaction of trichloroacetamide 13f with pyrrolidine.
Scheme 13: Catalytic hydrogenation of (arylmethylene)cyclopropropane 13f.
Scheme 14: Instability of trichloroacetimidates 21a–c derived from cyclopropenylcarbinols 20a–c.
Scheme 15: [3,3]-Sigmatropic rearrangement of cyanate 27 generated from cyclopropenylcarbinyl carbamate 26.
Scheme 16: Synthesis of alkylidene(aminocyclopropane) derivatives 30–37 from carbamate 26.
Scheme 17: Scope of the dehydration–[3,3]-sigmatropic rearrangement sequence of cyclopropenylcarbinyl carbamat...
Scheme 18: Formation of trifluoroacetamide 50 from carbamate 49.
Scheme 19: Formation of alkylidene[(N-trifluoroacetylamino)cyclopropanes] 51–54.
Scheme 20: Diastereoselective hydrogenation of alkylidenecyclopropane 51.
Scheme 21: Ireland–Claisen rearrangement of cyclopropenylcarbinyl glycolates 56a–l.
Scheme 22: Synthesis and Ireland–Claisen rearrangement of glycolate 61 possessing gem-diester substitution at ...
Scheme 23: Synthesis of alkylidene(gem-difluorocyclopropanes) 66a–h, and 66k–n from propargyl glycolates 64a–n....
Scheme 24: Ireland–Claisen rearrangement of N,N-diBoc glycinates 67a and 67b.
Scheme 25: Diastereoselective hydrogenation of alkylidenecyclopropanes 58a and 74.
Scheme 26: Synthesis of functionalized gem-difluorocyclopropanes 76 and 77 from alkylidenecyclopropane 66a.
Scheme 27: Access to oxa- and azabicyclic compounds 78–80.
Regioselective addition of Grignard reagents to N-acylpyrazinium salts: synthesis of substituted 1,2-dihydropyrazines and Δ5-2-oxopiperazines
- Valentine R. St. Hilaire,
- William E. Hopkins,
- Yenteeo S. Miller,
- Srinivasa R. Dandepally and
- Alfred L. Williams
Beilstein J. Org. Chem. 2019, 15, 72–78, doi:10.3762/bjoc.15.8
- nucleophilic addition of bis(trimethylsilyl)ketene acetals to pyrazines activated with methyl chloroformate was found to afford polycyclic γ-lactones in moderate yields [3][10][11]. The work by Garduño-Alva and co-workers demonstrated that these TMS-ketene acetals can be regioselectively added to substituted N
- the nucleophilic addition of Grignard reagents to N-acylpyrazinium salts. A literature search showed this organometallic reagent reacting with pyrazine N-oxides towards the one-pot synthesis of N-Boc-protected N-hydroxy-substituted piperazines in good yields [6]. Methylmagnesium iodide was observed
Graphical Abstract
Figure 1: Regioselective addition of Grignard reagents to mono- and disubstituted pyrazinium salts (yields re...
N-Arylphenothiazines as strong donors for photoredox catalysis – pushing the frontiers of nucleophilic addition of alcohols to alkenes
- Fabienne Speck,
- David Rombach and
- Hans-Achim Wagenknecht
Beilstein J. Org. Chem. 2019, 15, 52–59, doi:10.3762/bjoc.15.5
- broaden the substrate scope for the nucleophilic addition of methanol to styrenes through photoredox catalysis. These N-phenylphenothiazines differ by their electron-donating and electron-withdrawing substituents at the phenyl group, covering both, σ and π-type groups, in order to modulate their
- (without considering the solvent term) [29] we estimated the excited state potential of these catalysts to be as low as Ered(X+·/X*) ≈ −2.9 to −3.0 V (vs SCE). The proposed photoredox catalytic mechanism (Figure 4) for the nucleophilic addition of methanol to olefins starts with photoinduced electron
Graphical Abstract
Figure 1: Reduction potentials (vs SCE) of common photoredox catalysts, pyrene 16 and phenothiazine 2, in com...
Figure 2: Acceptor or donor-modified phenothiazines 1–11 as potential photoredox catalysts.
Figure 3: Normalized UV–vis absorption spectra above 290 nm of N-phenylphenothiazines 1–11 (left) and represe...
Figure 4: Proposed mechanism for the photoredox-catalyzed addition of methanol to α-methylstyrene (13a). (ET ...
Mn-mediated sequential three-component domino Knoevenagel/cyclization/Michael addition/oxidative cyclization reaction towards annulated imidazo[1,2-a]pyridines
- Olga A. Storozhenko,
- Alexey A. Festa,
- Delphine R. Bella Ndoutoume,
- Alexander V. Aksenov,
- Alexey V. Varlamov and
- Leonid G. Voskressensky
Beilstein J. Org. Chem. 2018, 14, 3078–3087, doi:10.3762/bjoc.14.287
- second step, target product 5a was not observed, and compound 22 was isolated in trace amounts. Its formation may be explained by an initial nucleophilic addition of water to intermediate chromene 3, oxidation to keto-derivative and condensation with nitromethane (Scheme 6, reaction 2, IV). Conclusion In
Graphical Abstract
Figure 1: Biologically relevant imidazo[1,2-a]pyridines and chromenes.
Scheme 1: Domino formation of imidazopyridines and current work.
Scheme 2: Scope of the reaction between N-(cyanomethyl)pyridinium chloride, o-hydroxybenzaldehydes, and nitro...
Scheme 3: Scope of the reaction of o-hydroxybenzaldehydes with N-(cyanomethyl)pyridinium chloride and indoles...
Scheme 4: Scope of the nucleophiles in the reaction of o-hydroxyarylaldehydes with N-(cyanomethyl)pyridinium ...
Scheme 5: N-(Cyanomethyl)thieno[2,3-c]pyridinium chloride (15) and 6-(cyanomethyl)-1-methyl-1H-pyrrolo[2,3-c]...
Figure 2: General view of the molecule 7b in the crystal state (CCDC 1849215). Anisotropic displacement param...
Scheme 6: The presumed mechanism for the formation of target chromenoimidazopyridines (reaction 1) and additi...
Synthesis of indole–cycloalkyl[b]pyridine hybrids via a four-component six-step tandem process
- Muthumani Muthu,
- Rakkappan Vishnu Priya,
- Abdulrahman I. Almansour,
- Raju Suresh Kumar and
- Raju Ranjith Kumar
Beilstein J. Org. Chem. 2018, 14, 2907–2915, doi:10.3762/bjoc.14.269
- condensation–nucleophilic addition to carbonyl–Michael addition–N-cyclization–elimination–air oxidation sequence to afford structurally intriguing indole–cycloalkyl[b]pyridine-3-carbonitrile hybrid heterocycles in excellent yields. Keywords: cycloalkyl[b]pyridine-3-carbonitrile; cyclododecanone; 3-(1H-indol-3
- –cycloalkyl[b]pyridine-3-carbonitrile hybrid heterocycles have been achieved through a facile one-pot four-component strategy. This reaction occurred through a six-step tandem Hantzsch-like process involving Knoevenagel–Michael–nucleophilic addition–intramolecular cyclization–elimination–oxidative
Graphical Abstract
Figure 1: Examples of biologically important cycloalkyl-fused pyridines.
Scheme 1: Synthesis of 3-oxopropanenitriles 3.
Scheme 2: Proposed mechanism for the formation of 7f.
Scheme 3: Synthesis of indole–cyclododeca[b]pyridine-3-carbonitriles 7 and 14.
Figure 2: Axial chirality due to restricted C–C bond rotation (representative cases).
Figure 3: ORTEP diagram of 12r.
Scheme 4: Synthesis of indole–cycloalkyl[b]pyridine-3-carbonitrile hybrids 15–18.
Figure 4: ORTEP diagram of 16f.
Hydroarylations by cobalt-catalyzed C–H activation
- Rajagopal Santhoshkumar and
- Chien-Hong Cheng
Beilstein J. Org. Chem. 2018, 14, 2266–2288, doi:10.3762/bjoc.14.202
- undergoes oxidative addition with arylpyridine to generate I1. Then, elimination of neopentane (R–H) by reductive elimination gives cobaltacycle I2. Nucleophilic addition of I2 to imines, followed by transmetallation with a Grignard reagent and protonation provide the desired hydroarylation product 57. In
- addition to imines, aziridines were also amenable to the cobalt-catalyzed hydroarylation reaction (Scheme 36) [96]. Treatment of 2-phenylpyridines 3 with varies aryl-substituted aziridines gave 1,1-diarylethane derivatives 58 in a highly regioselective manner. It is noteworthy that nucleophilic addition
Graphical Abstract
Scheme 1: Cobalt-catalyzed C–H carbonylation.
Scheme 2: Hydroarylation by C–H activation.
Scheme 3: Pathways for cobalt-catalyzed hydroarylations.
Scheme 4: Co-catalyzed hydroarylation of alkynes with azobenzenes.
Scheme 5: Co-catalyzed hydroarylation of alkynes with 2-arylpyridines.
Scheme 6: Co-catalyzed addition of azoles to alkynes.
Scheme 7: Co-catalyzed addition of indoles to alkynes.
Scheme 8: Co-catalyzed hydroarylation of alkynes with imines.
Scheme 9: A plausible pathway for Co-catalyzed hydroarylation of alkynes.
Scheme 10: Co-catalyzed anti-selective C–H addition to alkynes.
Scheme 11: Co(III)-catalyzed hydroarylation of alkynes with indoles.
Scheme 12: Co(III)-catalyzed branch-selective hydroarylation of alkynes.
Scheme 13: Co(III)-catalyzed hydroarylation of terminal alkynes with arenes.
Scheme 14: Co(III)-catalyzed hydroarylation of alkynes with amides.
Scheme 15: Co(III)-catalyzed C–H alkenylation of arenes.
Scheme 16: Co-catalyzed alkylation of substituted benzamides with alkenes.
Scheme 17: Co-catalyzed switchable hydroarylation of styrenes with 2-aryl pyridines.
Scheme 18: Co-catalyzed linear-selective hydroarylation of alkenes with imines.
Scheme 19: Co-catalyzed linearly-selective hydroarylation of alkenes with N–H imines.
Scheme 20: Co-catalyzed branched-selective hydroarylation of alkenes with imines.
Scheme 21: Mechanism of Co-catalyzed hydroarylation of alkenes.
Scheme 22: Co-catalyzed intramolecular hydroarylation of indoles.
Scheme 23: Co-catalyzed asymmetric hydroarylation of alkenes with indoles.
Scheme 24: Co-catalyzed hydroarylation of alkenes with heteroarenes.
Scheme 25: Co(III)-catalyzed hydroarylation of activated alkenes with 2-phenyl pyridines.
Scheme 26: Co(III)-catalyzed C–H alkylation of arenes.
Scheme 27: Co(III)-catalyzed C2-alkylation of indoles.
Scheme 28: Co(III)-catalyzed switchable hydroarylation of alkyl alkenes with indoles.
Scheme 29: Co(III)-catalyzed C2-allylation of indoles.
Scheme 30: Co(III)-catalyzed ortho C–H alkylation of arenes with maleimides.
Scheme 31: Co(III)-catalyzed hydroarylation of maleimides with arenes.
Scheme 32: Co(III)-catalyzed hydroarylation of allenes with arenes.
Scheme 33: Co-catalyzed hydroarylative cyclization of enynes with carbonyl compounds.
Scheme 34: Mechanism for the Co-catalyzed hydroarylative cyclization of enynes with carbonyl compounds.
Scheme 35: Co-catalyzed addition of 2-arylpyridines to aromatic aldimines.
Scheme 36: Co-catalyzed addition of 2-arylpyridines to aziridines.
Scheme 37: Co(III)-catalyzed hydroarylation of imines with arenes.
Scheme 38: Co(III)-catalyzed addition of arenes to ketenimines.
Scheme 39: Co(III)-catalyzed three-component coupling.
Scheme 40: Co(III)-catalyzed hydroarylation of aldehydes.
Scheme 41: Co(III)-catalyzed addition of arenes to isocyanates.
Synthesis of 1,4-imino-L-lyxitols modified at C-5 and their evaluation as inhibitors of GH38 α-mannosidases
- Maroš Bella,
- Sergej Šesták,
- Ján Moncoľ,
- Miroslav Koóš and
- Monika Poláková
Beilstein J. Org. Chem. 2018, 14, 2156–2162, doi:10.3762/bjoc.14.189
- be achieved via nucleophilic addition of MeMgBr to an aldehyde obtained by the oxidation of alcohol 7. Despite this fact, we did not manage the preparation of the aldehyde by the oxidation of alcohol 7 probably due to its instability [33]. However, similar aldehyde 17 bearing a Cbz protecting group
Graphical Abstract
Figure 1: Structures of GMIIb inhibitors.
Scheme 1: Synthesis of pyrrolidines 2a and 3a.
Scheme 2: Synthesis of pyrrolidines 2b,c and 3b,c.
Scheme 3: Synthesis of pyrrolidines 4.
Scheme 4: Synthesis of pyrrolidines 5.
Figure 2: Molecular structure (OLEX2 drawing with adjacent ChemDraw image) of compound 20. Atomic displacemen...
Studies towards the synthesis of hyperireflexolide A
- G. Hari Mangeswara Rao
Beilstein J. Org. Chem. 2018, 14, 2106–2111, doi:10.3762/bjoc.14.185
- of the proposed synthetic sequence. Future studies will include the stereoselective epoxidation of 11 followed by opening of the epoxide and lactonization or 1,4-nucleophilic addition to the α,β-unsaturated ketone 11 followed by epoxidation of the resulted enolate with subsequent lactonization to
Graphical Abstract
Figure 1: Hyperireflexolide A.
Scheme 1: Retrosynthetic strategy.
Scheme 2: Hydrolysis of dimethyl ketal 5.
Scheme 3: Alkylation of γ-lactone-fused β-ketoester 6.
Scheme 4: Synthesis of α,β-unsaturated ketone 11.
Functionalization of graphene: does the organic chemistry matter?
- Artur Kasprzak,
- Agnieszka Zuchowska and
- Magdalena Poplawska
Beilstein J. Org. Chem. 2018, 14, 2018–2026, doi:10.3762/bjoc.14.177
- ], the approach to the synthesis of the material has not been given in some cases; in other words, the researchers have not always discussed whether the process is based on the non-covalent adsorption of the reactant or whether it follows the nucleophilic addition to GO’s epoxides. On the basis of the
Graphical Abstract
Figure 1: Partial structure [7,8] of the (a) graphene oxide (GO) and (b) reduced graphene oxide (RGO).
Figure 2: Mechanism of the amidation/esterification-type reactions with the GO/RGO using carbodiimide and N-h...
Figure 3: Mechanism of the Steglich esterification with the GO/RGO: (a) acid–base reaction of the carboxyl gr...
Figure 4: Mechanism of the epoxide ring opening reaction with the GO/RGO.
Figure 5: Generation of the free amine (nucleophile) from the corresponding amine hydrohalide using an acid–b...
Figure 6: Mechanism of amidation/esterification-type reactions with the GO/RGO using 1,1’-carbonyldiimidazole...
Figure 7: Mechanism of the covalent functionalization of graphene-family material applying diazonium salts ch...
Cobalt-catalyzed nucleophilic addition of the allylic C(sp3)–H bond of simple alkenes to ketones
- Tsuyoshi Mita,
- Masashi Uchiyama,
- Kenichi Michigami and
- Yoshihiro Sato
Beilstein J. Org. Chem. 2018, 14, 2012–2017, doi:10.3762/bjoc.14.176
- regeneration of I. Alkoxide VI is converted to homoallylic alcohol 3aa by usual work-up. Conclusion In conclusion, we have successfully developed a cobalt-catalyzed nucleophilic addition of the C(sp3)–H bond of simple alkenes to ketones. This novel transformation could realize perfect branch selectivity for
Graphical Abstract
Figure 1: Precedent examples of catalytic allylic C(sp3)–H additions to carbonyl electrophiles.
Figure 2: Substrate scope for acetophenone derivatives. aPreparative scale synthesis using 1 mmol of 2a.
Figure 3: Substrate scope for α-olefins.
Figure 4: A possible catalytic cycle.
β-Hydroxy sulfides and their syntheses
- Mokgethwa B. Marakalala,
- Edwin M. Mmutlane and
- Henok H. Kinfe
Beilstein J. Org. Chem. 2018, 14, 1668–1692, doi:10.3762/bjoc.14.143
- group from succinimide 103 to the chiral pre-catalyst 104 to generate the active species 110 (Scheme 40). Reaction of the alkene with the active species 110 results to the formation of the thiiranium intermediate 111, which then undergoes a stereoselective nucleophilic addition to provide the thioethers
Graphical Abstract
Figure 1: Some sulfur-containing natural products.
Figure 2: Some natural products incorporating β-hydroxy sulfide moieties.
Figure 3: Some synthetic β-hydroxy sulfides of clinical value.
Scheme 1: Alumina-mediated synthesis of β-hydroxy sulfides, ethers, amines and selenides from epoxides.
Scheme 2: β-Hydroxy sulfide syntheses by ring opening of epoxides under different Lewis and Brønsted acid and...
Scheme 3: n-Bu3P-catalyzed thiolysis of epoxides and aziridines to provide the corresponding β-hydroxy and β-...
Scheme 4: Zinc(II) chloride-mediated thiolysis of epoxides.
Scheme 5: Thiolysis of epoxides and one-pot oxidation to β-hydroxy sulfoxides under microwave irradiation.
Scheme 6: Gallium triflate-catalyzed ring opening of epoxides and one-pot oxidation.
Scheme 7: Thiolysis of epoxides and one-pot oxidation to β-hydroxy sulfoxides using Ga(OTf)3 as a catalyst.
Scheme 8: Ring opening of epoxide using ionic liquids under solvent-free conditions.
Scheme 9: N-Bromosuccinimide-catalyzed ring opening of epoxides.
Scheme 10: LiNTf2-mediated epoxide opening by thiophenol.
Scheme 11: Asymmetric ring-opening of cyclohexene oxide with various thiols catalyzed by zinc L-tartrate.
Scheme 12: Catalytic asymmetric ring opening of symmetrical epoxides with t-BuSH catalyzed by (R)-GaLB (43) wi...
Scheme 13: Asymmetric ring opening of meso-epoxides by p-xylenedithiol catalyzed by a (S,S)-(salen)Cr complex.
Scheme 14: Desymmetrization of meso-epoxide with thiophenol derivatives.
Scheme 15: Enantioselective ring-opening reaction of meso-epoxides with ArSH catalyzed by a C2-symmetric chira...
Scheme 16: Enantioselective ring-opening reaction of stilbene oxides with ArSH catalyzed by a C2-symmetric chi...
Scheme 17: Asymmetric desymmetrization of meso-epoxides using BINOL-based Brønsted acid catalysts.
Scheme 18: Lithium-BINOL-phosphate-catalyzed desymmetrization of meso-epoxides with aromatic thiols.
Scheme 19: Ring-opening reactions of cyclohexene oxide with thiols by using CPs 1-Eu and 2-Tb.
Scheme 20: CBS-oxazaborolidine-catalyzed borane reduction of β-keto sulfides.
Scheme 21: Preparation of β-hydroxy sulfides via connectivity.
Scheme 22: Baker’s yeast-catalyzed reduction of sulfenylated β-ketoesters.
Scheme 23: Sodium-mediated ring opening of epoxides.
Scheme 24: Disulfide bond cleavage-epoxide opening assisted by tetrathiomolybdate.
Scheme 25: Proposed reaction mechanism of disulfide bond cleavage-epoxide opening assisted by tetrathiomolybda...
Scheme 26: Cyclodextrin-catalyzed difunctionalization of alkenes.
Scheme 27: Zinc-catalyzed synthesis of β-hydroxy sulfides from disulfides and alkenes.
Scheme 28: tert-Butyl hydroperoxide-catalyzed hydroxysulfurization of alkenes.
Scheme 29: Proposed mechanism of the radical hydroxysulfurization.
Scheme 30: Rongalite-mediated synthesis of β-hydroxy sulfides from styrenes and disulfides.
Scheme 31: Proposed mechanism of Rongalite-mediated synthesis of β-hydroxy sulfides from styrenes and disulfid...
Scheme 32: Copper(II)-catalyzed synthesis of β-hydroxy sulfides 15e,f from alkenes and basic disulfides.
Scheme 33: CuI-catalyzed acetoxysulfenylation of alkenes.
Scheme 34: CuI-catalyzed acetoxysulfenylation reaction mechanism.
Scheme 35: One-pot oxidative 1,2-acetoxysulfenylation of Baylis–Hillman products.
Scheme 36: Proposed mechanism for the oxidative 1,2-acetoxysulfination of Baylis–Hillman products.
Scheme 37: 1,2-Acetoxysulfenylation of alkenes using DIB/KI.
Scheme 38: Proposed reaction mechanism of the diacetoxyiodobenzene (DIB) and KI-mediated 1,2-acetoxysulfenylat...
Scheme 39: Catalytic asymmetric thiofunctionalization of unactivated alkenes.
Scheme 40: Proposed catalytic cycle for asymmetric sulfenofunctionalization.
Scheme 41: Synthesis of thiosugars using intramolecular thiol-ene reaction.
Scheme 42: Synthesis of leukotriene C-1 by Corey et al.: (a) N-(trifluoroacetyl)glutathione dimethyl ester (3 ...
Scheme 43: Synthesis of pteriatoxins with epoxide thiolysis to attain β-hydroxy sulfides. Reagents: (a) (1) K2...
Scheme 44: Synthesis of peptides containing a β-hydroxy sulfide moiety.
Scheme 45: Synthesis of diltiazem (12) using biocatalytic resolution of an epoxide followed by thiolysis.
Hypervalent organoiodine compounds: from reagents to valuable building blocks in synthesis
- Gwendal Grelier,
- Benjamin Darses and
- Philippe Dauban
Beilstein J. Org. Chem. 2018, 14, 1508–1528, doi:10.3762/bjoc.14.128
- transformations involving stoichiometric amounts of λ3- or λ5-iodanes, thus, has been improved by designing tandem reactions that allows for incorporating the aryl motif into the products through a subsequent one-pot nucleophilic addition or catalytic coupling reaction. This review summarizes the main
- to the triple bond of 22 to give the intermediate 26, followed by the reductive elimination of the trivalent iodine motif to afford the palladium-vinylidene 27. This would undergo a nucleophilic addition of the imine and a subsequent proto-demetallation to give enamine 29. A series of rearrangements
Graphical Abstract
Scheme 1: Strategies to address the issue of sustainability with polyvalent organoiodine reagents.
Scheme 2: Functionalization of ketones and alkenes with IBX.
Scheme 3: Functionalization of pyrroles with DMP.
Scheme 4: Catalytic benzoyloxy-trifluoromethylation reported by Szabó.
Scheme 5: Catalytic benzoyloxy-trifluoromethylation reported by Mideoka.
Scheme 6: Catalytic 1,4-benzoyloxy-trifluoromethylation of dienes.
Scheme 7: Catalytic benzoyloxy-trifluoromethylation of allylamines.
Scheme 8: Catalytic benzoyloxy-trifluoromethylation of enynes.
Scheme 9: Catalytic benzoyloxy-trifluoromethylation of allenes.
Scheme 10: Alkynylation of N-(aryl)imines with EBX for the formation of furans.
Scheme 11: Catalytic benzoyloxy-alkynylation of diazo compounds.
Scheme 12: Catalytic asymmetric benzoyloxy-alkynylation of diazo compounds.
Scheme 13: Catalytic 1,2-benzoyloxy-azidation of alkenes.
Scheme 14: Catalytic 1,2-benzoyloxy-azidation of enamides.
Scheme 15: Catalytic 1,2-benzoyloxy-iodination of alkenes.
Scheme 16: Seminal study with cyclic diaryl-λ3-iodane.
Scheme 17: Synthesis of alkylidenefluorenes from cyclic diaryl-λ3-iodanes.
Scheme 18: Synthesis of alkyne-substituted alkylidenefluorenes.
Scheme 19: Synthesis of phenanthrenes from cyclic diaryl-λ3-iodanes.
Scheme 20: Synthesis of dibenzocarbazoles from cyclic diaryl-λ3-iodanes.
Scheme 21: Synthesis of triazolophenantridines from cyclic diaryl-λ3-iodanes.
Scheme 22: Synthesis of functionalized benzoxazoles from cyclic diaryl-λ3-iodanes.
Scheme 23: Sequential difunctionalization of cyclic diaryl-λ3-iodanes.
Scheme 24: Double Suzuki–Miyaura coupling reaction of cyclic diaryl-λ3-iodanes.
Scheme 25: Synthesis of a δ-carboline from cyclic diaryl-λ3-iodane.
Scheme 26: Synthesis of N-(aryl)carbazoles from cyclic diaryl-λ3-iodanes.
Scheme 27: Synthesis of carbazoles from cyclic diaryl-λ3-iodanes.
Scheme 28: Synthesis of carbazoles and acridines from cyclic diaryl-λ3-iodanes.
Scheme 29: Synthesis of dibenzothiophenes from cyclic diaryl-λ3-iodanes.
Scheme 30: Synthesis of various sulfur heterocycles from cyclic diaryl-λ3-iodanes.
Scheme 31: Synthesis of dibenzothioheterocycles from cyclic diaryl-λ3-iodanes.
Scheme 32: Synthesis of dibenzosulfides and dibenzoselenides from cyclic diaryl-λ3-iodanes.
Scheme 33: Synthesis of dibenzosulfones from cyclic diaryl-λ3-iodanes.
Scheme 34: Seminal study with linear diaryl-λ3-iodanes.
Scheme 35: N-Arylation of benzotriazole with symmetrical diaryl-λ3-iodanes.
Scheme 36: Tandem catalytic C–H/N–H arylation of indoles with diaryl-λ3-iodanes.
Scheme 37: Tandem N-arylation/C(sp2)–H arylation with diaryl-λ3-iodanes.
Scheme 38: Catalytic intermolecular diarylation of anilines with diaryl-λ3-iodanes.
Scheme 39: Catalytic synthesis of diarylsulfides with diaryl-λ3-iodanes.
Scheme 40: α-Arylation of enolates using [bis(trifluoroacetoxy)iodo]arenes.
Scheme 41: Mechanism of the α-arylation using [bis(trifluoroacetoxy)iodo]arene.
Scheme 42: Catalytic nitrene additions mediated by [bis(acyloxy)iodo]arenes.
Scheme 43: Tandem of C(sp3)–H amination/sila-Sonogashira–Hagihara coupling.
Scheme 44: Tandem reaction using a λ3-iodane as an oxidant, a substrate and a coupling partner.
Scheme 45: Synthesis of 1,2-diarylated acrylamidines with ArI(OAc)2.
Synthesis of chiral 3-substituted 3-amino-2-oxindoles through enantioselective catalytic nucleophilic additions to isatin imines
- Hélène Pellissier
Beilstein J. Org. Chem. 2018, 14, 1349–1369, doi:10.3762/bjoc.14.114
- imines published since the beginning of 2015. Keywords: asymmetric synthesis; chiral 3-amino-2-oxindoles; chirality; isatin imines; nucleophilic addition; Introduction Chiral oxindoles represent an important class of products widely present in nature and exhibiting many biological activities. Among
Graphical Abstract
Scheme 1: Mannich reaction of N-Boc-isatin imines with ethyl nitroacetate (2) catalyzed by a cinchona alkaloi...
Scheme 2: Mannich reaction of N-Boc-isatin imines with 1,3-dicarbonyl compounds catalyzed by a cinchona alkal...
Scheme 3: Mannich reaction of N-alkoxycarbonylisatin imines with acetylacetone catalyzed by a cinchona alkalo...
Scheme 4: Mannich reaction of isatin-derived benzhydrylketimines with trimethylsiloxyfuran catalyzed by a pho...
Scheme 5: Mannich reaction of N-Boc-isatin imines with acetaldehyde catalyzed by a primary amine.
Scheme 6: Mannich reaction of N-Cbz-isatin imines with aldehydes catalyzed by L-diphenylprolinol trimethylsil...
Scheme 7: Addition of dimedone-derived enaminones to N-Boc-isatin imines catalyzed by a phosphoric acid.
Scheme 8: Addition of hydroxyfuran-2-one-derived enaminones to N-Boc-isatin imines catalyzed by a phosphoric ...
Scheme 9: Zinc-catalyzed Mannich reaction of N-Boc-isatin imines with silyl ketene imines.
Scheme 10: Tin-catalyzed Mannich reaction of N-arylisatin imines with an alkenyl trichloroacetate.
Scheme 11: Aza-Morita–Baylis–Hillman reaction of N-Boc-isatin imines with acrolein catalyzed by β-isocupreidin...
Scheme 12: Aza-Morita–Baylis–Hillman reaction of N-Boc-isatin imines with acrolein (35) catalyzed by α-isocupr...
Scheme 13: Aza-Morita–Baylis–Hillman reaction of N-Boc-isatin imines with maleimides catalyzed by β-isocupreid...
Scheme 14: Aza-Morita–Baylis–Hillman reaction of N-Boc-isatin imines with nitroolefins catalyzed by a cinchona...
Scheme 15: Friedel–Crafts reactions of N-Boc-isatin imines with 1 and 2-naphthols catalyzed by a cinchona alka...
Scheme 16: Friedel–Crafts reactions of N-alkoxycarbonyl-isatin imines with 1 and 2-naphthols catalyzed by a ci...
Scheme 17: Friedel–Crafts reaction of N-Boc-isatin imines with 6-hydroxyquinolines catalyzed by a cinchona alk...
Scheme 18: Aza-Henry reaction of N-Boc-isatin imines with nitromethane catalyzed by a bifunctional guanidine.
Scheme 19: Domino addition/cyclization reaction of N-Boc-isatin imines with 1,4-dithiane-2,5-diol (53) catalyz...
Scheme 20: Nickel-catalyzed additions of methanol and cumene hydroperoxide to N-Boc-isatin imines.
Scheme 21: Palladium-catalyzed addition of arylboronic acids to N-tert-butylsulfonylisatin imines.
A survey of chiral hypervalent iodine reagents in asymmetric synthesis
- Soumen Ghosh,
- Suman Pradhan and
- Indranil Chatterjee
Beilstein J. Org. Chem. 2018, 14, 1244–1262, doi:10.3762/bjoc.14.107
- aminoarylation of alkenes 53 to produce 54 (Scheme 11). The presence of a silyloxy group is essential to achieve high enantioselectivity in case of the oxyarylation [49]. The Lewis acid activates the hypervalent chiral iodine reagent and then adds to the alkene system. The nucleophilic addition of the internal
- oxy/amino group followed by the nucleophilic addition of the aryl group delivers the desired products 54. The key to success also lies on the enantiotopic face discrimination of the alkene by the lactate-based chiral iodine reagent. This difunctionalization strategy was further showcased by Muñiz et
Graphical Abstract
Scheme 1: An overview of different chiral iodine reagents or precursors thereof.
Scheme 2: Asymmetric oxidation of sulfides by chiral hypervalent iodine reagents.
Scheme 3: Oxidative dearomatization of naphthol derivatives by Kita et al.
Scheme 4: [4 + 2] Diels–Alder dimerization reported by Birman et al.
Scheme 5: m-CPBA guided catalytic oxidative naphthol dearomatization.
Scheme 6: Oxidative dearomatization of phenolic derivatives by Ishihara et al.
Scheme 7: Oxidative spirocyclization applying precatalyst 11 developed by Ciufolini et al.
Scheme 8: Asymmetric hydroxylative dearomatization.
Scheme 9: Enantioselective oxylactonization reported by Fujita et al.
Scheme 10: Dioxytosylation of styrene (47) by Wirth et al.
Scheme 11: Oxyarylation and aminoarylation of alkenes.
Scheme 12: Asymmetric diamination of alkenes.
Scheme 13: Stereoselective oxyamination of alkenes reported by Wirth et al.
Scheme 14: Enantioselective and regioselective aminofluorination by Nevado et al.
Scheme 15: Fluorinated difunctionalization reported by Jacobsen et al.
Scheme 16: Aryl rearrangement reported by Wirth et al.
Scheme 17: α-Arylation of β-ketoesters.
Scheme 18: Asymmetric α-oxytosylation of carbonyls.
Scheme 19: Asymmetric α-oxygenation and α-amination of carbonyls reported by Wirth et al.
Scheme 20: Asymmetric α-functionalization of ketophenols using chiral quaternary ammonium (hypo)iodite salt re...
Scheme 21: Oxidative Intramolecular coupling by Gong et al.
Scheme 22: α-Sulfonyl and α-phosphoryl oxylation of ketones reported by Masson et al.
Scheme 23: α-Fluorination of β-keto esters.
Scheme 24: Alkynylation of β-ketoesters and amides catalyzed by phase-transfer catalyst.
Scheme 25: Alkynylation of β-ketoesters and dearomative alkynylation of phenols.
Stereoselective nucleophilic addition reactions to cyclic N-acyliminium ions using the indirect cation pool method: Elucidation of stereoselectivity by spectroscopic conformational analysis and DFT calculations
- Koichi Mitsudo,
- Junya Yamamoto,
- Tomoya Akagi,
- Atsuhiro Yamashita,
- Masahiro Haisa,
- Kazuki Yoshioka,
- Hiroki Mandai,
- Koji Ueoka,
- Christian Hempel,
- Jun-ichi Yoshida and
- Seiji Suga
Beilstein J. Org. Chem. 2018, 14, 1192–1202, doi:10.3762/bjoc.14.100
Graphical Abstract
Scheme 1: Generation and reaction of cationic species generated by “indirect cation pool” methods.
Figure 1: (a) 1H NMR of N-acyliminium ion C1 in CD2Cl2 at −80 °C (600 MHz). (b) Preferred conformation of C1.
Figure 2: (a) 1H NMR spectrum of C3 in CD2Cl2 at −60 °C (400 MHz). (b) Preferred conformation of C3.
Figure 3: (a) 1H NMR spectrum of C5 in CD2Cl2 at −60 °C (400 MHz). (b) Preferred conformation of C5.
Figure 4: Summary of the conformations of N-acyliminium ions C1–C6.
Figure 5: Stevens’ hypothesis on the tendency of the addition of nucleophiles to N-acyliminium ions. The subs...
Figure 6: A plausible mechanism of the observed diastereoselective reaction of the N-acyliminium ions.
Figure 7: Comparison of ΔG for the pseudo-equatorial and pseudo-axial conformations of C1–C6 at the B3LYP/6-3...
One hundred years of benzotropone chemistry
- Arif Dastan,
- Haydar Kilic and
- Nurullah Saracoglu
Beilstein J. Org. Chem. 2018, 14, 1120–1180, doi:10.3762/bjoc.14.98
- as a fairly air-stable red-brown solid. b. Nucleophilic addition to 4,5-benzotropone (11): Ried’s group realized the reaction of 4,5-benzotropone (11) and its derivatives with lithium acetylide as a nucleophile between −50 and −32 °C [130]. While the possible 1,4-conjugate addition product 149 was
Graphical Abstract
Scheme 1: Tropone (1), tropolone (2) and their resonance structures.
Figure 1: Natural products containing a tropone nucleus.
Figure 2: Possible isomers 11–13 of benzotropone.
Scheme 2: Synthesis of benzotropones 11 and 12.
Scheme 3: Oxidation products of benzotropylium fluoroborate (16).
Scheme 4: Oxidation of 7-bromo-5H-benzo[7]annulene (22).
Scheme 5: Synthesis of 4,5-benzotropone (11) using o-phthalaldehyde (27).
Scheme 6: Synthesis of 4,5-benzotropone (11) starting from oxobenzonorbornadiene 31.
Scheme 7: Acid-catalyzed cleavage of oxo-bridge of 34.
Scheme 8: Synthesis of 4,5-benzotropone (11) from o-xylylene dibromide (38).
Scheme 9: Synthesis of 4,5-benzotropone (11) via the carbene adduct 41.
Scheme 10: Heck coupling strategy for the synthesis of 11.
Scheme 11: Synthesis of benzofulvalenes via carbonyl group of 4,5-benzotropone (11).
Figure 3: Some cycloheptatrienylium cations.
Scheme 12: Synthesis of condensation product 63 and its subsequent oxidative cyclization products.
Figure 4: A novel series of benzo[7]annulenes prepared from 4,5-benzotropone (11).
Scheme 13: Preparation of substituted benzo[7]annulene 72 using the Mukaiyama-Michael reaction.
Figure 5: Possible benzo[7]annulenylidenes 73–75.
Scheme 14: Thermal and photochemical decomposition of 7-diazo-7H-benzo[7]annulene (76) and the trapping of int...
Scheme 15: Synthesis of benzoheptafulvalene 86.
Scheme 16: Synthesis of 7-(diphenylmethylene)-7H-benzo[7]annulene (89).
Scheme 17: Reaction of 4,5-benzotropone (11) with dimethyl diazomethane.
Scheme 18: Synthesis of dihydrobenzomethoxyazocine 103.
Scheme 19: Synthesis and reducibility of benzo-homo-2-methoxyazocines.
Scheme 20: Synthesis of 4,5-benzohomotropones 104 and 115 from 4,5-benzotropones 11 and 113.
Scheme 21: A catalytic deuterogenation of 4,5-benzotropone (11) and synthesis of 5-monosubstituted benzo[7]ann...
Scheme 22: Synthesis of methyl benzo[7]annulenes 131 and 132.
Scheme 23: Ambident reactivity of halobenzo[7]annulenylium cations 133a/b.
Scheme 24: Preparation of benzo[7]annulenylidene–iron complexes 147.
Scheme 25: Synthesis of 1-ethynylbenzotropone (150) and the etheric compound 152 from 4,5-benzotropone (11) wi...
Scheme 26: Thermal decomposition of 4,5-benzotropone (11).
Scheme 27: Reaction of 4,5-benzotropone (11) with 1,2-ethanediol and 1,2-ethanedithiol.
Scheme 28: Conversions of 1-benzosuberone (162) to 2,3-benzotropone (12).
Scheme 29: Synthesis strategies for 2,3-bezotropone (12) using 1-benzosuberones.
Scheme 30: Oxidation-based synthesis of 2,3-benzotropone (12) via 1-benzosuberone (162).
Scheme 31: Synthesis of 2,3-benzotropone (12) from α-tetralone (171) via ring-expansion.
Scheme 32: Preparation of 2,3-benzotropone (12) by using of benzotropolone 174.
Figure 6: Benzoheptafulvenes as condensation products of 2,3-benzotropone (12).
Scheme 33: Conversion of 2,3-benzotropone (12) to tosylhydrazone salt 182 and gem-dichloride 187.
Figure 7: Benzohomoazocines 191–193 and benzoazocines 194–197.
Scheme 34: From 2,3-benzotropone (12) to carbonium ions 198–201.
Scheme 35: Cycloaddition reactions of 2,3-benzotropone (12).
Scheme 36: Reaction of 2,3-benzotropone (12) with various reagents and compounds.
Figure 8: 3,4-Benzotropone (13) and its resonance structure.
Scheme 37: Synthesis of 6,7-benzobicyclo[3.2.0]hepta-3,6-dien-2-one (230).
Figure 9: Photolysis and thermolysis products of 230.
Figure 10: Benzotropolones and their tautomeric structures.
Scheme 38: Synthesis strategies of 4,5-benzotropolone (238).
Scheme 39: Synthesis protocol for 2-hydroxy-4,5-benzotropone (238) using oxazole-benzo[7]annulene 247.
Figure 11: Some quinoxaline and pyrazine derivatives 254–256 prepared from 4,5-benzotropolone (238).
Scheme 40: Nitration product of 4,5-benzotropolone (238) and its isomerization to 1-nitro-naphthoic acid (259)....
Scheme 41: Synthesis protocol for 6-hydroxy-2,3-benzotropone (239) from benzosuberone (162).
Scheme 42: Various reactions via 6-hydroxy-2,3-benzotropone (239).
Scheme 43: Photoreaction of 6-hydroxy-2,3-benzotropone (239).
Scheme 44: Synthesis of 7-hydroxy-2,3-benzotropone (241) from benzosuberone (162).
Scheme 45: Synthesis strategy for 7-hydroxy-2,3-benzotropone (241) from ketone 276.
Scheme 46: Synthesis of 7-hydroxy-2,3-benzotropone (241) from β-naphthoquinone (280).
Scheme 47: Synthesis of 7-hydroxy-2,3-benzotropone (241) from bicyclic endoperoxide 213.
Scheme 48: Synthesis of 7-hydroxy-2,3-benzotropone (241) by ring-closing metathesis.
Figure 12: Various monosubstitution products 289–291 of 7-hydroxy-2,3-benzotropone (241).
Scheme 49: Reaction of 7-hydroxy-2,3-benzotropone (241) with various reagents.
Scheme 50: Synthesis of 4-hydroxy-2,3-benzotropones 174 and 304 from diketones 300/301.
Scheme 51: Catalytic hydrogenation of diketones 300 and 174.
Scheme 52: Synthesis of halo-benzotropones from alkoxy-naphthalenes 306, 307 and 310.
Figure 13: Unexpected byproducts 313–315 during synthesis of chlorobenzotropone 309.
Figure 14: Some halobenzotropones and their cycloadducts.
Scheme 53: Multisep synthesis of 2-chlorobenzotropone 309.
Scheme 54: A multistep synthesis of 2-bromo-benzotropone 26.
Scheme 55: A multistep synthesis of bromo-2,3-benzotropones 311 and 316.
Scheme 56: Oxidation reactions of 8-bromo-5H-benzo[7]annulene (329) with some oxidants.
Scheme 57: Synthesis of 2-bromo-4,5-benzotropone (26).
Scheme 58: Synthesis of 6-chloro-2,3-benzotropone (335) using LiCl and proposed intermediate 336.
Scheme 59: Reaction of 7-bromo-2,3-benzotropone (316) with methylamine.
Scheme 60: Reactions of bromo-2,3-benzotropones 26 and 311 with dimethylamine.
Scheme 61: Reactions of bromobenzotropones 311 and 26 with NaOMe.
Scheme 62: Reactions of bromobenzotropones 26 and 312 with t-BuOK in the presence of DPIBF.
Scheme 63: Cobalt-catalyzed reductive cross-couplings of 7-bromo-2,3-benzotropone (316) with cyclic α-bromo en...
Figure 15: Cycloadduct 357 and its di-π-methane rearrangement product 358.
Scheme 64: Catalytic hydrogenation of 2-chloro-4,5-benzotropone (311).
Scheme 65: Synthesis of dibromo-benzotropones from benzotropones.
Scheme 66: Bromination/dehydrobromination of benzosuberone (162).
Scheme 67: Some transformations of isomeric dibromo-benzotropones 261A/B.
Scheme 68: Transformations of benzotropolone 239B to halobenzotropolones 369–371.
Figure 16: Bromobenzotropolones 372–376 and 290 prepared via bromination/dehydrobromination strategy.
Scheme 69: Synthesis of some halobenzotropolones 289, 377 and 378.
Figure 17: Bromo-chloro-derivatives 379–381 prepared via chlorination.
Scheme 70: Synthesis of 7-iodo-3,4-benzotropolone (382).
Scheme 71: Hydrogenation of bromobenzotropolones 369 and 370.
Scheme 72: Debromination reactions of mono- and dibromides 290 and 375.
Figure 18: Nitratation and oxidation products of some halobenzotropolenes.
Scheme 73: Azo-coupling reactions of some halobenzotropolones 294, 375 and 378.
Figure 19: Four possible isomers of dibenzotropones 396–399.
Figure 20: Resonance structures of tribenzotropone (400).
Scheme 74: Two synthetic pathways for tribenzotropone (400).
Scheme 75: Synthesis of tribenzotropone (400) from dibenzotropone 399.
Scheme 76: Synthesis of tribenzotropone (400) from 9,10-phenanthraquinone (406).
Scheme 77: Synthesis of tribenzotropone (400) from trifluoromethyl-substituted arene 411.
Figure 21: Dibenzosuberone (414).
Figure 22: Reduction products 415 and 416 of tribenzotropone (400).
Figure 23: Structures of tribenzotropone dimethyl ketal 417 and 4-phenylfluorenone (412) and proposed intermed...
Figure 24: Structures of benzylidene- and methylene-9H-tribenzo[a,c,e][7]annulenes 419 and 420 and chiral phos...
Figure 25: Structures of tetracyclic alcohol 422, p-quinone methide 423 and cation 424.
Figure 26: Structures of host molecules 425–427.
Scheme 78: Synthesis of non-helical overcrowded derivatives syn/anti-431.
Figure 27: Hexabenzooctalene 432.
Figure 28: Structures of possible eight isomers 433–440 of naphthotropone.
Scheme 79: Synthesis of naphthotropone 437 starting from 1-phenylcycloheptene (441).
Scheme 80: Synthesis of 10-hydroxy-11H-cyclohepta[a]naphthalen-11-one (448) from diester 445.
Scheme 81: Synthesis of naphthotropone 433.
Scheme 82: Synthesis of naphthotropones 433 and 434 via cycloaddition reaction.
Scheme 83: Synthesis of naphthotropone 434 starting from 452.
Figure 29: Structures of tricarbonyl(tropone)irons 458, and possible cycloadducts 459.
Scheme 84: Synthesis of naphthotropone 436.
Scheme 85: Synthesis of precursor 465 for naphthotropone 435.
Scheme 86: Generation of naphthotropone 435 from 465.
Figure 30: Structures of tropylium cations 469 and 470.
Figure 31: Structures of tropylium ions 471+.BF4−, 472+.BF4−, and 473+.BF4−.
Scheme 87: Synthesis of tropylium ions 471+.BF4− and 479+.ClO4−.
Scheme 88: Synthesis of 1- and 2-methylanthracene (481 and 482) via carbene–carbene rearrangement.
Figure 32: Trapping products 488–490.
Scheme 89: Generation and chemistry of a naphthoannelated cycloheptatrienylidene-cycloheptatetraene intermedia...
Scheme 90: Proposed intermediates and reaction pathways for adduct 498.
Scheme 91: Exited-state intramolecular proton transfer of 505.
Figure 33: Benzoditropones 506 and 507.
Scheme 92: Synthesis of benzoditropone 506e.
Scheme 93: Synthetic approaches for dibenzotropone 507 via tropone (1).
Scheme 94: Formation mechanisms of benzoditropone 507 and 516 via 515.
Scheme 95: Synthesis of benzoditropones 525 and 526 from pyromellitic dianhydride (527).
Figure 34: Possible three benzocyclobutatropones 534–536.
Scheme 96: Synthesis of benzocyclobutatropones 534 and 539.
Scheme 97: Synthesis attempts for benzocyclobutatropone 545.
Scheme 98: Generation and trapping of symmetric benzocyclobutatropone 536.
Scheme 99: Synthesis of chloro-benzocyclobutatropone 552 and proposed mechanism of fluorenone derivatives.
Scheme 100: Synthesis of tropolone analogue 559.
Scheme 101: Synthesis of tropolones 561 and 562.
Figure 35: o/p-Tropoquinone rings (563 and 564) and benzotropoquinones (565–567).
Scheme 102: Synthesis of benzotropoquinone 566.
Scheme 103: Synthesis of benzotropoquinone 567 via a Diels–Alder reaction.
Figure 36: Products 575–577 through 1,2,3-benzotropoquinone hydrate 569.
Scheme 104: Structures 578–582 prepared from tropoquinone 567.
Figure 37: Two possible structures 583 and 584 for dibenzotropoquinone, and precursor compound 585 for 583.
Scheme 105: Synthesis of saddle-shaped ketone 592 using dibenzotropoquinone 584.
Recent advances in synthetic approaches for medicinal chemistry of C-nucleosides
- Kartik Temburnikar and
- Katherine L. Seley-Radtke
Beilstein J. Org. Chem. 2018, 14, 772–785, doi:10.3762/bjoc.14.65
- that is also based on the nucleophilic substitution of ribonolactone. Review Nucleophilic addition to D-ribonolactone and its stereochemistry Two prominent methods of C-nucleoside syntheses involve either i) the linear construction of a (hetero)aryl moiety on a C1'-functionalized ribose or ii) coupling
Graphical Abstract
Figure 1: Structural components of nucleic acids. Shown is the monomeric building block of nucleic acids. Cha...
Figure 2: Formation of oxocarbenium ion during glycosidic bond cleavage in nucleosides [31]. The extent of leavin...
Figure 3: Structural modifications to nucleobase-sugar connectivity. The O–C–N bond between nucleobase and su...
Figure 4: Examples of natural and synthetic C-nucleosides. Pseudouridine and formcycin are among several natu...
Figure 5: Synthetic approaches to C-nucleosides. A. Two common strategies for C-nucleoside synthesis involve ...
Figure 6: Steroselective C-nucleoside synthesis using D-ribonolactone. A. Nucleophilic substitution of D-ribo...
Figure 7: Synthesis of C1'-substituted 4-aza-7,9-dideazaadenine C-nucleosides [63-65,69,70]. A. Reaction of D-ribonolacton...
Figure 8: Pyrrolo- and imidazo[2,1-f][1,2,4]triazine C-nucleosides. A series of sugar- and nucleobase-substit...
Figure 9: Synthesis of 1',2'-cyclopentyl C-nucleoside [73]. Functional groups at C1' and C2' were installed and e...
Figure 10: Anti-influenza C-nucleosides mimicking favipiravir riboside [74]. A. Structure of favipiravir and its r...
Figure 11: Alternative method for synthesis of 2'-substituted C-nucleosides [75]. A. Synthesis of C2'-substituted ...
Figure 12: Synthesis of carbocyclic C-nucleosides using cyclopentanone [53]. A. Nucleophlic substitution on cyclop...
Figure 13: Synthesis of carbocyclic C-nucleosides via Suzuki coupling [53]. A. Synthesis of OTf-cyclopentene that ...
Mannich base-connected syntheses mediated by ortho-quinone methides
- Petra Barta,
- Ferenc Fülöp and
- István Szatmári
Beilstein J. Org. Chem. 2018, 14, 560–575, doi:10.3762/bjoc.14.43
- and the aldehyde yields a Schiff base and then the latter reacts with 2-naphthol in the second nucleophilic addition step. The other theory assumes the formation of an ortho-quinone methide (o-QM) intermediate by the reaction of 2-naphthol and benzaldehyde. Re-aromatization, the driving force of the
- transformation, takes place in the second step by the nucleophilic addition of the amine component. The class of o-QMs has recently been investigated from many aspects. They are known as short-lived species playing an important role as key intermediates in numerous synthetic pathways. Reviews have recently been
- the desired 1-amidoalkyl-2-naphthol derivatives. This second step can also be considered as a nucleophilic addition of the amide to the o-QM component. Various catalysts and conditions were used to optimize reaction conditions considering economical and environmental aspects. These include microwave
Graphical Abstract
Scheme 1: Formation of amidoalkylnaphthols 4 via o-QM intermediate 3.
Scheme 2: Asymmetric syntheses of triarylmethanes starting from diarylmethylamines.
Scheme 3: Proposed mechanism for the formation of 2,2-dialkyl-3-dialkylamino-2,3-dihydro-1H-naphtho[2,1-b]pyr...
Scheme 4: Cycloadditions of isoflavonoid-derived o-QMs and various dienophiles.
Scheme 5: [4 + 2] Cycloaddition reactions between aminonaphthols and cyclic amines.
Scheme 6: Brønsted acid-catalysed reaction between aza-o-QMs and 2- or 3-substituted indoles.
Scheme 7: Formation of 3-(α,α-diarylmethyl)indoles 52 in different synthetic pathways.
Scheme 8: Alkylation of o-QMs with N-, O- or S-nucleophiles.
Scheme 9: Formation of DNA linkers and o-QM mediated polymers.
Functionalization of N-arylglycine esters: electrocatalytic access to C–C bonds mediated by n-Bu4NI
- Mi-Hai Luo,
- Yang-Ye Jiang,
- Kun Xu,
- Yong-Guo Liu,
- Bao-Guo Sun and
- Cheng-Chu Zeng
Beilstein J. Org. Chem. 2018, 14, 499–505, doi:10.3762/bjoc.14.35
- homogeneous reaction with N-arylglycine esters, N-iodo intermediate 4 was generated. Eliminating a molecule of HI affords imine intermediate 5. In the presence of acetic acid, the protonated 5-H+ undergoes nucleophilic addition with C–H nucleophiles 2 to give the desired products 3. Conclusion In summary, an
Graphical Abstract
Scheme 1: Cross dehydrogenative coupling of N-arylglycine esters with C–H nucleophiles.
Scheme 2: Electrochemical CDC reaction of 2a and various N-arylglycine esters. Reaction conditions for the in...
Scheme 3: Scope of 2 using n-Bu4NI as mediator. Reaction conditions:1a (0.5 mmol), 2 (0.6 mmol), n-Bu4NI (30 ...
Scheme 4: Scaling up.
Scheme 5: Control experiments.
Scheme 6: A plausible mechanism for the electrocatalytic cross dehydrogenative coupling of N-arylglycine este...
Recent developments in the asymmetric Reformatsky-type reaction
- Hélène Pellissier
Beilstein J. Org. Chem. 2018, 14, 325–344, doi:10.3762/bjoc.14.21
- nucleophilic addition of ethyl iodoacetate to the Si face of the cyclic imine 67 affording the final β-amino ester 68 and regenerating dimer M. In 2017, a related chiral ligand 69 employed at only 10–20 mol % of catalyst loading was reported by the same authors to be capable of catalyzing in combination with
Graphical Abstract
Scheme 1: Reformatsky-type reaction.
Scheme 2: First total synthesis of prunustatin A based on a Zn-mediated Reformatsky reaction [17].
Scheme 3: Synthesis of a γ-hydroxylysine derivative through a Zn-mediated nitrile Reformatsky-type reaction [18].
Scheme 4: Synthesis of apratoxin E and its C30 epimer through a Zn-mediated Reformatsky reaction. Fmoc = 9-fl...
Scheme 5: Synthesis of the eastern fragment of jatrophane diterpene Pl-3 through a SmI2-mediated Reformatsky ...
Scheme 6: First total synthesis of prebiscibactin through a SmI2-mediated Reformatsky reaction. Boc = tert-bu...
Scheme 7: Synthesis of prostaglandin E2 methyl ester through a SmI2-mediated Reformatsky reaction [23].
Scheme 8: Synthesis of the C1–C11 fragment of tedanolide C through a SnCl2-mediated Reformatsky reaction. PMB...
Scheme 9: Synthesis of β-trifluoromethyl β-(N-tert-butylsulfinyl)amino esters exhibiting a quaternary stereoc...
Scheme 10: Synthesis of α,α-difluoro-β-(N-tert-butylsulfinyl)amino esters through Zn(II)-mediated aza-Reformat...
Scheme 11: Synthesis of a common fragment to anti-apoptotic protein inhibitors through a Zn-mediated aza-Refor...
Scheme 12: Synthesis of α,α-difluoro-β-(N-tert-butylsulfinyl)amino ketones through a Zn-mediated aza-Reformats...
Scheme 13: Synthesis of (2-oxoindolin-3-yl)amino esters through a Zn-mediated aza-Reformatsky reaction [30].
Scheme 14: Synthesis of a precursor of sacubitril through a Zn-mediated aza-Reformatsky reaction [31].
Scheme 15: Synthesis of epothilone D through a Cr(II)-mediated Reformatsky reaction. TFA = trifluoroacetic aci...
Scheme 16: Synthesis of β-hydroxy-α-methyl-δ-trichloromethyl-δ-valerolactone through a Sm(II)- or Yb(II)-media...
Scheme 17: Synthesis of cebulactam A1 through a Sm(II)-mediated Reformatsky reaction. MOM = methoxymethyl [34].
Scheme 18: Synthesis of ansamacrolactams (+)-Q-1047H-A-A and (+)-Q-1047H-R-A through a Sm(II)-mediated Reforma...
Scheme 19: Reformatsky reaction of aldehydes with ethyl iodoacetate in the presence of a chiral 1,2-amino alco...
Scheme 20: Reformatsky reaction of aldehydes with ethyl bromoacetate in the presence of a chiral amide ligand [44]....
Scheme 21: Reformatsky reaction of cinnamaldehyde with ethyl bromozinc-α,α-difluoroacetate in the presence of ...
Scheme 22: Reformatsky reaction of aldehydes with an enolate equivalent prepared from phenyl isocyanate and CH2...
Scheme 23: Domino aza-Reformatsky/cyclization reactions of imines with ethyl dibromofluoroacetate in the prese...
Scheme 24: Domino aza-Reformatsky/cyclization reactions of imines with ethyl bromodifluoroacetate in the prese...
Scheme 25: Aza-Reformatsky reactions of cyclic imines with ethyl iodoacetate in the presence of a chiral diary...
Scheme 26: Mechanism for aza-Reformatsky reaction of cyclic imines with ethyl iodoacetate in the presence of a...
Scheme 27: Aza-Reformatsky reaction of dibenzo[b,f][1,4]oxazepines and dibenzo[b,f][1,4]thiazepine with ethyl ...
Nucleophilic fluoroalkylation/cyclization route to fluorinated phthalides
- Masanori Inaba,
- Tatsuya Sakai,
- Shun Shinada,
- Tsuyuka Sugiishi,
- Yuta Nishina,
- Norio Shibata and
- Hideki Amii
Beilstein J. Org. Chem. 2018, 14, 182–186, doi:10.3762/bjoc.14.12
- practical method for the synthesis of C3-perfluoroalkyl-substituted phthalides in a one-pot manner. Upon treatment of KF or triethylamine, 2-cyanobenzaldehyde reacted with (perfluoroalkyl)trimethylsilanes via nucleophilic addition and subsequent intramolecular cyclization to give perfluoroalkylphthalides in
Graphical Abstract
Scheme 1: Phthalide and fluorinated phthalides (1).
Scheme 2: Plausible reaction mechanism for the formation of phthalide 1a.
Scheme 3: Synthesis of fluorinated phthalides 1.
Scheme 4: Asymmetric synthesis of 1a using a chiral auxiliary.
Scheme 5: Catalytic asymmetric synthesis of 1a.
