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Search for "silver" in Full Text gives 302 result(s) in Beilstein Journal of Organic Chemistry. Showing first 200.
Aromatic systems with two and three pyridine-2,6-dicarbazolyl-3,5-dicarbonitrile fragments as electron-transporting organic semiconductors exhibiting long-lived emissions
- Karolis Leitonas,
- Brigita Vigante,
- Dmytro Volyniuk,
- Audrius Bucinskas,
- Pavels Dimitrijevs,
- Sindija Lapcinska,
- Pavel Arsenyan and
- Juozas Vidas Grazulevicius
Beilstein J. Org. Chem. 2023, 19, 1867–1880, doi:10.3762/bjoc.19.139
- experiments were carried out in a controlled environment with 0.1 M tetrabutylammonium hexafluorophosphate as the electrolyte and anhydrous dichloromethane as the solvent, maintaining room temperature conditions under a nitrogen atmosphere. To ensure accurate potential measurements, the system utilized silver
Graphical Abstract
Figure 1: Chemical structures of pyridine-3,5-dicarbonitrile-based TADF emitters.
Scheme 1: Synthesis of dicyanocarbazole 6. Reaction conditions: a) cyanoacetamide, piperidine, methanol, 40 °...
Scheme 2: Synthesis of dicyanocarbazoles 7–9. Reaction conditions: a) corresponding ethynyl arene, Pd(Ph3P)4 ...
Figure 2: Absorption (a, b) and PL (c, d) spectra of dilute toluene, THF, and chloroform solutions (10−5 M) a...
Figure 3: PL spectra (a) and PL decay curves (b) of air-equilibrated (as prepared) and deoxygenated toluene s...
Figure 4: Non-normalized (a) and normalized (b) PL spectra and PL decay curves (c) of the film of a 10 wt % m...
Figure 5: TGA (a) and DSC 2nd heating (b) curves of compounds 6–9.
Figure 6: CV curves of compounds 6–9.
Figure 7: Photoelectron emission spectra of the vacuum-deposited films of compounds 6–9 on glass substrates c...
Figure 8: The current transients (a) for electrons recorded at the different voltages for the vacuum-deposite...
Application of N-heterocyclic carbene–Cu(I) complexes as catalysts in organic synthesis: a review
- Nosheen Beig,
- Varsha Goyal and
- Raj K. Bansal
Beilstein J. Org. Chem. 2023, 19, 1408–1442, doi:10.3762/bjoc.19.102
- consecutive treatment of the corresponding azolium salts with silver oxide and copper chloride (Scheme 25). The X-ray structure of one of the complexes, [(TPrXyl)CuCl], revealed that the NHC–Cu–Cl bond angle is 177.8°, indicating almost linearity. These synthesized complexes were also used as efficient
- catalysts for hydrosilylation and [3 + 2] cycloaddition discussed later [39]. 1.4 By ligand displacement Corrigan and co-worker stabilized homoleptic copper- and silver bis(trimethylsilyl)phosphido compounds [M6{P(SiMe3)2}6] (M = Cu, Ag) through their coordination with NHC ligands. For this purpose, they
- used 1,3-diisopropylbenzimidazol-2-ylidene (iPr2-bimy) and 1,3-bis(2,6-diisopropylphenyl)imidazol-2-ylidene (IPr) (Scheme 28) [40]. The structures of all the synthesized complexes were confirmed by X-ray crystallography. A similar strategy was followed for stabilizing copper- and silver tert
Graphical Abstract
Scheme 1: In situ generation of imidazolylidene carbene.
Scheme 2: Hg(II) complex of NHC.
Scheme 3: Isolable and bottlable carbene reported by Arduengo [3].
Scheme 4: First air-stable carbene synthesized by Arduengo in 1992 [5].
Figure 1: General structure of an NHC.
Figure 2: Stabilization of an NHC by donation of the lone pair electrons into the vacant p-orbital (LUMO) at ...
Figure 3: Abnormal NHC reported by Bertrand [8,9].
Figure 4: Cu(d) orbital to σ*C-N(NHC) interactions in NHC–CuX complexes computed at the B3LYP/def2-SVP level ...
Figure 5: Molecular orbital contributions to the NHC–metal bond.
Scheme 5: Synthesis of NHC–Cu(I) complexes by deprotonation of NHC precursors with a base.
Scheme 6: Synthesis of [NHC–CuX] complexes.
Scheme 7: Synthesis of [(ICy)CuX] and [(It-Bu)CuX] complexes.
Scheme 8: Synthesis of iodido-bridged copper–NHC complexes by deprotonation of benzimidazolium salts reported...
Scheme 9: Synthesis of copper complexes by deprotonation of triazolium salts.
Scheme 10: Synthesis of thiazolylidene–Cu(I) complex by deprotonation with KOt-Bu.
Scheme 11: Preparation of NHC–Cu(I) complexes.
Scheme 12: Synthesis of methylmalonic acid-derived anionic [(26a,b)CuCl]Li(THF)2 and zwitterionic (28) heterol...
Scheme 13: Synthesis of diaminocarbene and diamidocarbene (DAC)–Cu(I) complexes.
Scheme 14: Synthesis of the cationic (NHC)2Cu(I) complex 39 from benzimidazolium salts 38 with tetrakis(aceton...
Scheme 15: Synthesis of NHC and ADC (acyclic diamino carbenes) Cu(I) hexamethyldisilazide complexes reported b...
Scheme 16: Synthesis of NHC–copper(I) complexes using an acetylacetonate-functionalized imidazolium zwitterion...
Scheme 17: Synthesis of NHC–Cu(I) complexes through deprotonation of azolium salts with Cu2O.
Scheme 18: Synthesis of NHC–CuBr complex through deprotonation with Cu2O reported by Kolychev [31].
Scheme 19: Synthesis of chiral NHC–CuBr complexes from phenoxyimine-imidazolium salts reported by Douthwaite a...
Scheme 20: Preparation of linear neutral NHC–CuCl complexes through the use of Cu2O. For abbreviations, please...
Scheme 21: Synthesis of abnormal-NHC–copper(I) complexes by Bertrand, Cazin and co-workers [35].
Scheme 22: Microwave-assisted synthesis of thiazolylidene/benzothiazolylidene–CuBr complexes by Bansal and co-...
Scheme 23: Synthesis of NHC–CuX complexes through transmetallation.
Scheme 24: Preparation of six- or seven-membered NHC–Cu(I) complexes through transmetalation from Ag(I) comple...
Scheme 25: Synthesis of 1,2,3-triazolylidene–CuCl complexes through transmetallation of Ag(I) complexes genera...
Scheme 26: Synthesis of NHC–copper complexes having both Cu(I) and Cu(II) units through transmetalation report...
Scheme 27: Synthesis of new [(IPr(CH2)3Si(OiPr)3)CuX] complexes and anchoring on MCM-41.
Scheme 28: Synthesis of bis(trimethylsilyl)phosphide–Cu(I)–NHC complexes through ligand displacement.
Scheme 29: Synthesis of silyl- and stannyl [(NHC)Cu−ER3] complexes.
Scheme 30: Synthesis of amido-, phenolato-, thiophenolato–Cu(NHC) complexes.
Scheme 31: Synthesis of first isolable NHC–Cu–difluoromethyl complexes reported by Sanford et al. [44].
Scheme 32: Synthesis of NHC–Cu(I)–bifluoride complexes reported by Riant, Leyssens and co-workers [45].
Scheme 33: Conjugate addition of Et2Zn to enones catalyzed by an NHC–Cu(I) complex reported by Woodward in 200...
Scheme 34: Hydrosilylation of a carbonyl group.
Scheme 35: NHC–Cu(I)-catalyzed hydrosilylation of ketones reported by Nolan et al. [48,49].
Scheme 36: Application of chiral NHC–CuCl complex 104 for the enantioselective hydrosilylation of ketones.
Scheme 37: Hydrosilylation reactions catalyzed by NHC–Cu(Ot-Bu) complexes.
Scheme 38: NHC–CuCl catalyzed carbonylative silylation of alkyl halides.
Scheme 39: Nucleophilic conjugate addition to an activated C=C bond.
Figure 6: Molecular electrostatic potential maps (MESP) of two NHC–CuX complexes computed at the B3LYP/def2-S...
Scheme 40: Conjugate addition of Grignard reagents to 3-alkyl-substituted cyclohexenones catalyzed by a chiral...
Scheme 41: NHC–copper complex-catalyzed conjugate addition of Grignard reagent to 3-substituted hexenone repor...
Scheme 42: Conjugate addition or organoaluminum reagents to β-substituted cyclic enones.
Scheme 43: Conjugate addition of boronates to acyclic α,β-unsaturated carboxylic esters, ketones, and thioeste...
Scheme 44: NHC–Cu(I)-catalyzed hydroboration of an allene reported by Hoveyda [63].
Scheme 45: Conjugate addition of Et2Zn to cyclohexenone catalyzed by NHC–Cu(I) complex derived from benzimidaz...
Scheme 46: Asymmetric conjugate addition of diethylzinc to 3-nonen-2-one catalyzed by NHC–Cu complexes derived...
Scheme 47: General scheme of a [3 + 2] cycloaddition reaction.
Scheme 48: [3 + 2] Cycloaddition of azides with alkynes catalyzed by NHC–Cu(I) complexes reported by Diez-Gonz...
Scheme 49: Application of NHC–CuCl/N-donor combination to catalyze the [3 + 2] cycloaddition of benzyl azide w...
Scheme 50: [3 + 2] Cycloaddition of azides with acetylenes catalyzed by bis(NHC)–Cu complex 131 and mixed NHC–...
Figure 7: NHC–CuCl complex 133 as catalyst for the [3 + 2] cycloaddition of alkynes with azides at room tempe...
Scheme 51: [3 + 2] Cycloaddition of a bulky azide with an alkynylpyridine using [(NHC)Cu(μ-I)2Cu(NHC)] copper ...
Scheme 52: [3 + 2] Cycloaddition of benzyl azide with phenylacetylene under homogeneous and heterogeneous cata...
Scheme 53: [3 + 2] Cycloaddition of benzyl azide with acetylenes catalyzed by bisthiazolylidene dicopper(I) co...
Figure 8: Copper (I)–NHC linear coordination polymer 137 and its conversion into tetranuclear (138) and dinuc...
Scheme 54: An A3 reaction.
Scheme 55: Synthesis of SiO2-immobilized NHC–Cu(I) catalyst 141 and its application in the A3-coupling reactio...
Scheme 56: Preparation of dual-purpose Ru@SiO2–[(NHC)CuCl] catalyst system 142 developed by Bordet, Leitner an...
Scheme 57: Application of the catalyst system Ru@SiO2–[Cu(NHC)] 142 to the one-pot tandem A3 reaction and hydr...
Scheme 58: A3 reaction of phenylacetylene with secondary amines and aldehydes catalyzed by benzothiazolylidene...
Figure 9: Kohn–Sham HOMOs of phenylacetylene and NHC–Cu(I)–phenylacetylene complex computed at the B3LYP/def2...
Figure 10: Energies of the FMOs of phenylacetylene, iminium ion, and NHC–Cu(I)–phenylacetylene complex compute...
Scheme 59: NHC–Cu(I) catalyzed diboration of ketones 147 by reacting with bis(pinacolato)diboron (148) reporte...
Scheme 60: Protoboration of terminal allenes catalyzed by NHC–Cu(I) complexes reported by Hoveyda and co-worke...
Scheme 61: NHC–CuCl-catalyzed borylation of α-alkoxyallenes to give 2-boryl-1,3-butadienes.
Scheme 62: Regioselective hydroborylation of propargylic alcohols and ethers catalyzed by NHC–CuCl complexes 1...
Scheme 63: NHC–CuOt-Bu-catalyzed semihydrogenation and hydroborylation of alkynes.
Scheme 64: Enantioselective NHC–Cu(I)-catalyzed hydroborations of 1,1-disubstituted aryl olefins reported by H...
Scheme 65: Enantioselective NHC–Cu(I)-catalyzed hydroboration of exocyclic 1,1-disubstituted alkenes reported ...
Scheme 66: Markovnikov-selective NHC–CuOH-catalyzed hydroboration of alkenes and alkynes reported by Jones et ...
Scheme 67: Dehydrogenative borylation and silylation of styrenes catalyzed by NHC–CuOt-Bu complexes developed ...
Scheme 68: N–H/C(sp2)–H carboxylation catalyzed by NHC–CuOH complexes.
Scheme 69: C–H Carboxylation of benzoxazole and benzothiazole derivatives with CO2 using a 1,2,3-triazol-5-yli...
Scheme 70: Use of Cu(I) complex derived from diethylene glycol-functionalized imidazo[1,5,a] pyridin-3-ylidene...
Scheme 71: Allylation and alkenylation of polyfluoroarenes and heteroarenes catalyzed by NHC–Cu(I) complexes r...
Scheme 72: Enantioselective C(sp2)–H allylation of (benz)oxazoles and benzothiazoles with γ,γ-disubstituted pr...
Scheme 73: C(sp2)–H arylation of arenes catalyzed by dual NHC–Cu/NHC–Pd catalytic system.
Scheme 74: C(sp2)–H Amidation of (hetero)arenes with N-chlorocarbamates/N-chloro-N-sodiocarbamates catalyzed b...
Scheme 75: NHC–CuI catalyzed thiolation of benzothiazoles and benzoxazoles.
Synthesis of ether lipids: natural compounds and analogues
- Marco Antônio G. B. Gomes,
- Alicia Bauduin,
- Chloé Le Roux,
- Romain Fouinneteau,
- Wilfried Berthe,
- Mathieu Berchel,
- Hélène Couthon and
- Paul-Alain Jaffrès
Beilstein J. Org. Chem. 2023, 19, 1299–1369, doi:10.3762/bjoc.19.96
- derivative 2.6. The treatment of 2.6 with trimethylamine produced an ammonium salt. A treatment with silver carbonate was applied to remove any traces of bromide salts. Then, the secondary alcohol was deprotected by hydrogenolysis to produce 2.7 (lyso-PAF). Finally, the acetylation of the secondary alcohol
- remove the acetal protecting group thus producing 22.2. Then, the primary alcohol was protected by reaction with tritylpyridinium tetrafluoroborate salt to produce 22.3. In the next step, the secondary alcohol was methylated with iodomethane in the presence of silver salts (AgBF4) and silver base (Ag2CO3
Graphical Abstract
Figure 1: Chemical structure of some natural ether lipids (ELs).
Figure 2: Synthesis of lyso-PAF and PAF from 1-O-alkylglycerol [64].
Figure 3: Synthesis of lyso-PAF from 1,3-benzylideneglycerol 3.1 [69].
Figure 4: A) Synthesis of the two enantiomers of octadecylglycerol (4.6 and 4.10) from ᴅ-mannitol (4.1); B) s...
Figure 5: Four-step synthesis of PAF 5.6 from (S)-glycidol [73].
Figure 6: Synthesis of 1-O-alkylglycerol A) from solketal, B) from ᴅ- or ʟ-tartaric acid and the intermediate ...
Figure 7: Synthesis of EL building blocks starting from substituted glycidol 7.1a–c [82].
Figure 8: Synthesis of PAF 8.5 by using phosphoramidite 8.2 [86].
Figure 9: Synthesis of oleyl-PAF 9.7 from ʟ-serine [88].
Figure 10: Synthesis of racemic analogues of lyso-PAF 10.8 and PAF 10.9 featuring a phenyl group between the g...
Figure 11: Synthesis of racemic deoxy-lyso-PAF 11.7 and deoxy-PAF 11.8 [91].
Figure 12: Synthesis of racemic thio-PAF 12.8 [93].
Figure 13: Racemic synthesis of 13.6 to illustrate the modification of the glycerol backbone by adding a methy...
Figure 14: Racemic synthesis of 14.5 as an illustration of the introduction of methyl substituents on the glyc...
Figure 15: Synthesis of functionalized sn-2-acyl chains of PC-EL; A) Steglich esterification or acylation reac...
Figure 16: Synthesis of racemic mc-PAF (16.3), a carbamate analogue of PAF [102].
Figure 17: A) Synthesis of (R)-17.2 and (S)-17.6 starting from (S)-solketal (17.1); B) synthesis of N3-PAF (17...
Figure 18: Modification of the phosphocholine polar head to produce PAF analogues [81].
Figure 19: Racemic PAF analogues 19.3 and 19.5 characterized by the absence of the phosphate group [107].
Figure 20: Synthesis of PIP3-PAF (20.7) [108].
Figure 21: Large-scale synthesis of C18-edelfosine (21.8) [116].
Figure 22: Synthesis of C16-edelfosine (22.10) starting from isopropylidene-ʟ-glyceric acid methyl ester (22.1...
Figure 23: Phosphocholine moiety installation by the use of chlorophosphite 23.2 as key reagent [119].
Figure 24: Synthesis of rac-1-alkyl-2-O-methylglycerol (AMG) [120].
Figure 25: Synthesis of stereocontrolled 1-alkyl-2-O-methyl glycerol 25.9 (AMG) from dimethyl ᴅ-tartrate [81].
Figure 26: A) Racemic synthesis of thioether 26.4 [129,130], B) structure of sulfone analogue 26.5 [129].
Figure 27: Stereocontrolled synthesis of C18-edelfosine thioether analogue 27.8 [118].
Figure 28: Synthesis of thioether 28.4 that include a thiophosphate function [134].
Figure 29: Synthesis of ammonium thioether 29.4 and 29.6 [135].
Figure 30: Synthesis of the N-methylamino analogue of edelfosine 30.6 (BN52211) [138].
Figure 31: Synthesis of 1-desoxy analogues of edelfosine; A) with a saturated alkyl chain; B) synthesis of the...
Figure 32: Stereocontrolled synthesis of edelfosine analogue (S)-32.8 featuring a C18:1 lipid chain [142].
Figure 33: Synthesis of edelfosine analogues with modulation of the lipid chain; A) illustration with the synt...
Figure 34: Synthesis of phospholipid featuring a carbamate function to link the lipid chain to the glycerol un...
Figure 35: Synthesis of sesquiterpene conjugates of phospho glycero ether lipids [148].
Figure 36: Racemic synthesis of methyl-substituted glycerol analogues 36.7 and 36.10: A) synthesis of diether ...
Figure 37: Racemic synthesis of ilmofosine (37.6) [155,156].
Figure 38: A) Stereoselective synthesis of 38.5 via a stereoselective hydroboration reaction; B) synthesis of ...
Figure 39: Racemic synthesis of SRI62-834 (39.6) featuring a spiro-tetrahydrofurane heterocycle in position 2 ...
Figure 40: Racemic synthesis of edelfosine analogue 40.5 featuring an imidazole moiety in sn-2 position [160].
Figure 41: Racemic synthesis of fluorine-functionalized EL: A) Synthesis of 41.6 and B) synthesis of 41.8 [161-163].
Figure 42: A) Synthesis of the β-keto-ester 42.6 that also features a decyl linker between the phosphate and t...
Figure 43: Synthesis of phosphonate-based ether lipids; A) edelfosine phosphonate analogue 43.7 and B) thioeth...
Figure 44: Enantioselective synthesis of phosphonates 44.3 and 44.4 [171].
Figure 45: Racemic synthesis of phosphinate-based ether lipid 45.10 [172].
Figure 46: Racemic synthesis of edelfosine arsonium analogue 46.5 [173].
Figure 47: Synthesis of edelfosine dimethylammonium analogue 47.2 [118].
Figure 48: Synthesis of rac-C18-edelfosine methylammonium analogue 48.4 [176].
Figure 49: A) Synthesis of edelfosine N-methylpyrrolidinium analogue 49.2 or N-methylmorpholinium analogue 49.3...
Figure 50: A) Synthesis of edelfosine’s analogue 50.4 with a PE polar group; B) illustration of a pyridinium d...
Figure 51: A) Synthesis of 51.4 featuring a thiazolium cationic moiety; B) synthesis of thiazolium-based EL 51...
Figure 52: Synthesis of cationic ether lipids 52.3, 52.4 and 52.6 [135,183].
Figure 53: Synthesis of cationic carbamate ether lipid 53.5 [184].
Figure 54: Synthesis of cationic sulfonamide 54.5 [185].
Figure 55: Chemical structure of ONO-6240 (55.1) and SRI-63-119 (55.2).
Figure 56: Synthesis of non-ionic ether lipids 56.2–56.9 [188].
Figure 57: Synthesis of ether lipid conjugated to foscarnet 57.6 [189].
Figure 58: A) Synthesis of ether lipid conjugated to arabinofuranosylcytosine; B) synthesis of AZT conjugated ...
Figure 59: Synthesis of quercetin conjugate to edelfosine [191].
Figure 60: Synthesis of 60.8 (Glc-PAF) [194].
Figure 61: A) Synthesis of amino ether lipid 61.7 functionalized with a rhamnose unit and its amide analogue 6...
Figure 62: A) Synthesis of glucose ether lipid 62.4; B) structure of ether lipid 62.5 possessing a maltose uni...
Figure 63: A) Synthesis of glucuronic methyl ester 63.8; B) structure of cellobiose 63.9 and maltose 63.10 ana...
Figure 64: A) Synthesis of maltosyl glycerolipid 64.7; B) structure of lactose analogue 64.8 prepared followin...
Figure 65: A) Asymmetric synthesis of the aglycone moiety starting from allyl 4-methoxyphenyl ether; B) glycos...
Figure 66: A) Synthesis of ohmline possessing a lactose moiety. B) Structure of other glyco glycero lipids pre...
Figure 67: A) Synthesis of lactose-glycerol ether lipid 67.5; B) analogues possessing a maltose (67.6) or meli...
Figure 68: Synthesis of digalactosyl EL 68.6, A) by using trityl, benzyl and acetyl protecting groups, B) by u...
Figure 69: A) Synthesis of α-ohmline; B) structure of disaccharide ether lipids prepared by using similar meth...
Figure 70: Synthesis of lactose ether lipid 70.3 and its analogue 70.6 featuring a carbamate function as linke...
Figure 71: Synthesis of rhamnopyranoside diether 71.4 [196].
Figure 72: Synthesis of 1-O-hexadecyl-2-O-methyl-3-S-(α-ᴅ-1'-thioglucopyranosyl)-sn-glycerol (72.5) [225].
Figure 73: A) Preparation of lipid intermediate 73.4; B) synthesis of 2-desoxy-C-glycoside 73.10 [226].
Figure 74: Synthesis of galactose-pyridinium salt 74.3 [228].
Figure 75: Synthesis of myo-inositol derivative Ino-C2-PAF (75.10) [230].
Figure 76: A) Synthesis of myo-inositol phosphate building block 76.7; B) synthesis of myo-inositolphosphate d...
Figure 77: A) Synthesis of phosphatidyl-3-desoxy-inositol 77.4; B) synthesis of phosphono-3-desoxyinositol 77.9...
Figure 78: A) Structure of diether phosphatidyl-myo-inositol-3,4-diphosphate 78.1; B) synthesis of phosphatidy...
Figure 79: A) Synthesis of diether-phosphatidyl derivative 79.4 featuring a hydroxymethyl group in place of a ...
Figure 80: Synthesis of Glc-amine-PAF [78].
Figure 81: Synthesis of glucosamine ether lipid 81.4 and its analogues functionalized in position 3 of the ami...
Figure 82: Synthesis of fully deprotected aminoglucoside ether lipid 82.5 [246].
Figure 83: Synthesis of C-aminoglycoside 83.12 using Ramberg–Bäcklund rearrangement as a key step [250].
Figure 84: A) List of the most important glyco lipids and amino glyco lipids included in the study of Arthur a...
Figure 85: Synthesis of mannosamine ether lipid 85.6 [254].
Figure 86: A) Synthesis of glucosamine ether lipids with a non-natural ʟ-glucosamine moiety; B) synthesis of e...
Figure 87: A) Structure of the most efficient anticancer agents 87.1–87.4 featuring a diamino glyco ether lipi...
Figure 88: A) Synthesis of diamino glyco ether lipid 87.4; B) synthesis of bis-glycosylated ether lipid 88.10 [256]....
Figure 89: Synthesis of triamino ether lipid 89.4 [260].
Figure 90: Synthesis of chlorambucil conjugate 90.7 [261].
Figure 91: Three main methods for the preparation of glycerol ether lipid 91.3; A) from solketal and via a tri...
Figure 92: Four different methods for the installation of the phosphocholine polar head group; A) method using...
Figure 93: Illustration of two methods for the installation of saccharides or aminosaccharides; A) O-glycosyla...
Pyridine C(sp2)–H bond functionalization under transition-metal and rare earth metal catalysis
- Haritha Sindhe,
- Malladi Mounika Reddy,
- Karthikeyan Rajkumar,
- Akshay Kamble,
- Amardeep Singh,
- Anand Kumar and
- Satyasheel Sharma
Beilstein J. Org. Chem. 2023, 19, 820–863, doi:10.3762/bjoc.19.62
- (Scheme 30). The reaction showed good compatibility with various functional groups. The proposed mechanism (Scheme 30b) involves the silver-catalyzed decarboxylation of heteroaryl acid 156 followed by transmetalation providing palladium intermediate 160. Further, C–H activation of pyridine N-oxide 9
- and 163 through a two-fold C–H activation under palladium catalysis. Silver carbonate and 2,6-lutidine were found to be an effective base and ligand, respectively, for providing the desired products 164 and 165 in good yields (Scheme 31). In 2015, an economic route for copper-catalyzed biaryl coupling
- of pyridine at the C2 and C3 position (Scheme 35a). Further, during optimization when silver additives like Ag2CO3, Ag2O, and AgOAc were used the reaction resulted in the formation of isoquinoline derivative 181. In addition, the reaction showed high regioselectivity in the presence of unsymmetrical
Graphical Abstract
Figure 1: Representative examples of bioactive natural products and FDA-approved drugs containing a pyridine ...
Scheme 1: Classical and traditional methods for the synthesis of functionalized pyridines.
Scheme 2: Rare earth metal (Ln)-catalyzed pyridine C–H alkylation.
Scheme 3: Pd-catalyzed C–H alkylation of pyridine N-oxide.
Scheme 4: CuI-catalyzed C–H alkylation of N-iminopyridinium ylides with tosylhydrazones (A) and a plausible r...
Scheme 5: Zirconium complex-catalyzed pyridine C–H alkylation.
Scheme 6: Rare earth metal-catalyzed pyridine C–H alkylation with nonpolar unsaturated substrates.
Scheme 7: Heterobimetallic Rh–Al complex-catalyzed ortho-C–H monoalkylation of pyridines.
Scheme 8: Mono(phosphinoamido)-rare earth complex-catalyzed pyridine C–H alkylation.
Scheme 9: Rhodium-catalyzed pyridine C–H alkylation with acrylates and acrylamides.
Scheme 10: Ni–Al bimetallic system-catalyzed pyridine C–H alkylation.
Scheme 11: Iridium-catalyzed pyridine C–H alkylation.
Scheme 12: para-C(sp2)–H Alkylation of pyridines with alkenes.
Scheme 13: Enantioselective pyridine C–H alkylation.
Scheme 14: Pd-catalyzed C2-olefination of pyridines.
Scheme 15: Ru-catalyzed C-6 (C-2)-propenylation of 2-arylated pyridines.
Scheme 16: C–H addition of allenes to pyridines catalyzed by half-sandwich Sc metal complex.
Scheme 17: Pd-catalyzed stereodivergent synthesis of alkenylated pyridines.
Scheme 18: Pd-catalyzed ligand-promoted selective C3-olefination of pyridines.
Scheme 19: Mono-N-protected amino acids in Pd-catalyzed C3-alkenylation of pyridines.
Scheme 20: Amide-directed and rhodium-catalyzed C3-alkenylation of pyridines.
Scheme 21: Bimetallic Ni–Al-catalyzed para-selective alkenylation of pyridine.
Scheme 22: Arylboronic ester-assisted pyridine direct C–H arylation.
Scheme 23: Pd-catalyzed C–H arylation/benzylation with toluene.
Scheme 24: Pd-catalyzed pyridine C–H arylation with potassium aryl- and heteroaryltrifluoroborates.
Scheme 25: Transient activator strategy in pyridine C–H biarylation.
Scheme 26: Ligand-promoted C3-arylation of pyridine.
Scheme 27: Pd-catalyzed arylation of nicotinic and isonicotinic acids.
Scheme 28: Iron-catalyzed and imine-directed C–H arylation of pyridines.
Scheme 29: Pd–(bipy-6-OH) cooperative system-mediated direct pyridine C3-arylation.
Scheme 30: Pd-catalyzed pyridine N-oxide C–H arylation with heteroarylcarboxylic acids.
Scheme 31: Pd-catalyzed C–H cross-coupling of pyridine N-oxides with five-membered heterocycles.
Scheme 32: Cu-catalyzed dehydrative biaryl coupling of azine(pyridine) N-oxides and oxazoles.
Scheme 33: Rh(III)-catalyzed cross dehydrogenative C3-heteroarylation of pyridines.
Scheme 34: Pd-catalyzed C3-selective arylation of pyridines.
Scheme 35: Rhodium-catalyzed oxidative C–H annulation of pyridines to quinolines.
Scheme 36: Rhodium-catalyzed and NHC-directed C–H annulation of pyridine.
Scheme 37: Ni/NHC-catalyzed regio- and enantioselective C–H cyclization of pyridines.
Scheme 38: Rare earth metal-catalyzed intramolecular C–H cyclization of pyridine to azaindolines.
Scheme 39: Rh-catalyzed alkenylation of bipyridine with terminal silylacetylenes.
Scheme 40: Rollover cyclometallation in Rh-catalyzed pyridine C–H functionalization.
Scheme 41: Rollover pathway in Rh-catalyzed C–H functionalization of N,N,N-tridentate chelating compounds.
Scheme 42: Pd-catalyzed rollover pathway in bipyridine-6-carboxamides C–H arylation.
Scheme 43: Rh-catalyzed C3-acylmethylation of bipyridine-6-carboxamides with sulfoxonium ylides.
Scheme 44: Rh-catalyzed C–H functionalization of bipyridines with alkynes.
Scheme 45: Rh-catalyzed C–H acylmethylation and annulation of bipyridine with sulfoxonium ylides.
Scheme 46: Iridium-catalyzed C4-borylation of pyridines.
Scheme 47: C3-Borylation of pyridines.
Scheme 48: Pd-catalyzed regioselective synthesis of silylated dihydropyridines.
Strategies in the synthesis of dibenzo[b,f]heteropines
- David I. H. Maier,
- Barend C. B. Bezuidenhoudt and
- Charlene Marais
Beilstein J. Org. Chem. 2023, 19, 700–718, doi:10.3762/bjoc.19.51
- % yield via a gold/silver catalyst system (Scheme 27). 4 Oxidative C–C coupling Whereas oxidative C–C coupling precedes amination in the industrial route to 5H-dibenzo[b,f]azepine, oxidative C–C coupling may also be the final step in the construction of the dibenzo[b,f]heteropine skeleton. Comber and
Graphical Abstract
Figure 1: Dibenzo[b,f]azepine (1a), -oxepine (1b) and -thiepine (1c) as examples of dibenzo[b,f]heteropines (1...
Figure 2: Selected pharmaceuticals with the dibenzo[b,f]azepine skeleton.
Figure 3: Examples of 10,11-dihydrodibenzo[b,f]azepine-based ligands.
Figure 4: The dibenzo[b,f]azepine moiety in dyes with properties suitable for the use in organic light emitti...
Figure 5: Selective bioactive natural products (13–18) containing the dibenzo[b,f]oxepine scaffold and Novart...
Scheme 1: Retrosynthetic approach to 5H-dibenzo[b,f]azepine (1a) from nitrotoluene (22).
Scheme 2: Oxidative coupling of o-nitrotoluene (22) and reduction of 2,2'-dinitrobibenzyl (21) to form 2,2'-d...
Scheme 3: Synthesis of 10,11-dihydro-5H-dibenzo[b,f]azepine (2a) via amine condensation.
Scheme 4: Catalytic reduction of 10,11-dihydro-5H-dibenzo[b,f]azepine (2a).
Scheme 5: The Wagner–Meerwein rearrangement of acridin-9-ylmethanol (23) into 5H-dibenzo[b,f]azepine (1a).
Scheme 6: Oxidative ring expansion of 2-(9-xanthenyl)malonates 24.
Scheme 7: Ring expansion via C–H functionalisation.
Scheme 8: The synthesis of fluorinated 5H-dibenzo[b,f]azepine 38 from isatin (32).
Scheme 9: The synthesis of substituted dibenzo[b,f]azepines 43 from indoles 39.
Scheme 10: Retrosynthetic pathways to dibenzo[b,f]azepines via Buchwald–Hartwig amination.
Scheme 11: Synthesis of dibenzo[b,f]oxepine 54 and -azepine 55 derivatives via (i) Heck reaction and (ii) Buch...
Scheme 12: Double Buchwald–Hartwig amination and thioetherification in the synthesis of tricyclic azepines 60 ...
Scheme 13: Double Buchwald–Hartwig amination towards substituted dibenzoazepines 62.
Scheme 14: Double Buchwald–Hartwig amination towards 10,11-dihydro-5H-dibenzo[b,f]azepine derivatives 71.
Scheme 15: One-pot Suzuki coupling–Buchwald–Hartwig amination.
Scheme 16: One-pot Rh/Pd-catalysed synthesis of dihydropyridobenzazepines.
Scheme 17: A retrosynthetic pathway to dibenzo[b,f]azepines via Mizoroki–Heck reaction.
Scheme 18: One-pot domino Pd-catalyzed Mizoroki–Heck–Buchwald–Hartwig synthesis of dibenzo[b,f]azepines.
Scheme 19: Dibenzo[b,f]thiapine and -oxepine synthesis via SNAr (thio)etherification, Wittig methylenation and...
Scheme 20: A retrosynthetic pathway to dibenzo[b,f]oxepines via Ullmann coupling.
Scheme 21: Ullmann-type coupling in dibenzo[b,f]oxepine synthesis.
Scheme 22: Wittig reaction and Ullmann coupling as key steps in dihydrobenz[b,f]oxepine synthesis.
Scheme 23: Pd-catalysed dibenzo[b,f]azepine synthesis via norbornene azepine intermediate 109.
Scheme 24: A simple representation of olefin metathesis resulting in transalkylidenation.
Scheme 25: Ring-closing metathesis as key step in the synthesis of dibenzo[b,f]heteropines.
Scheme 26: Alkyne–aldehyde metathesis in the synthesis of dibenzo[b,f]heteropines.
Scheme 27: Hydroarylation of 9-(2-alkynylphenyl)-9H-carbazole derivatives.
Scheme 28: Oxidative coupling of bisphonium ylide intermediate to give pacharin (13).
Scheme 29: Preparation of 10,11-dihydrodibenzo[b,f]heteropines via intramolecular Wurtz reaction.
Scheme 30: Phenol deprotonation and intramolecular etherification in the synthesis of bauhinoxepine J.
Figure 6: Functionalisation of dibenzo[b,f]azepine.
Scheme 31: Palladium-catalysed N-arylation of dibenzo[b,f]azepine.
Scheme 32: Cu- and Ni-catalysed N-arylation.
Scheme 33: N-Alkylation of dibenzo[b,f]azepine (1a) and dihydrodibenzo[b,f]azepine (2a).
Scheme 34: Preparation of methoxyiminosilbene.
Scheme 35: Synthesis of oxcarbazepine (153) from methoxy iminostilbene 151.
Scheme 36: Ring functionalisation of dihydrodibenzo[b,f]azepine.
Mechanochemical solid state synthesis of copper(I)/NHC complexes with K3PO4
- Ina Remy-Speckmann,
- Birte M. Zimmermann,
- Mahadeb Gorai,
- Martin Lerch and
- Johannes F. Teichert
Beilstein J. Org. Chem. 2023, 19, 440–447, doi:10.3762/bjoc.19.34
- sophisticated copper(I)/N-heterocyclic carbene complex bearing a guanidine moiety. In this way, the present approach circumvents commonly employed silver(I) complexes which are associated with significant and undesired waste formation and the excessive use of solvents. The resulting bifunctional catalyst has
- “built-in base” route relies on the use of Cu2O which can be directly reacted with a suitable NHC precursor 1 (Scheme 1c) [28]. In any case, the most common approach hinges upon the use of the preliminary preparation of an intermediate silver(I)/NHC complex followed by facile transmetallation to copper(I
- simultaneous organocatalytic activation of the ester on the other hand. Following a previously established synthetic pathway [49], we have found that transmetallation via silver(I)/NHC complex 4 was the only viable synthetic entry point to this sophisticated bifunctional catalyst (Scheme 2) [10][12][14][50
Graphical Abstract
Scheme 1: General synthetic routes to copper(I)/NHC complexes (X = Cl, Br).
Scheme 2: Preparation of sophisticated Cu(I)/NHC complexes: Synthesis of bifunctional catalyst 5 via transmet...
Scheme 3: Application of bifunctional catalyst 5 in copper(I)-catalyzed hydrogenations: comparison of 5 prepa...
Group 13 exchange and transborylation in catalysis
- Dominic R. Willcox and
- Stephen P. Thomas
Beilstein J. Org. Chem. 2023, 19, 325–348, doi:10.3762/bjoc.19.28
- achieved. When AgOTf was replaced with silver (R)-BINOL phosphate, the asymmetric allylation proceeded in a moderate yield (60%) and enantioselectivity (40% ee). The structure of the ‘GaIOTf’ species was explored in more detail by Slattery, and a monovalent [GaI(18-crown-6)OTf] complex was isolated and
Graphical Abstract
Scheme 1: Group 13 exchange.
Scheme 2: Borane-catalysed hydroboration of alkynes and the proposed mechanism.
Scheme 3: a) Borane-catalysed hydroboration of alkenes and the proposed mechanism. b) H-B-9-BBN-catalysed dou...
Scheme 4: a) Amine-borane-catalysed C‒H borylation of heterocycles and the proposed mechanism. b) Benzoic aci...
Scheme 5: Bis(pentafluorophenyl)borane-catalysed dimerisation of allenes and the proposed mechanism.
Scheme 6: Alkoxide-promoted hydroboration of heterocycles and the proposed mechanism.
Scheme 7: Borane-catalysed reduction of indoles and the proposed mechanism.
Scheme 8: H-B-9-BBN-catalysed hydrocyanation of enones and the proposed mechanism.
Scheme 9: Borane-catalysed hydroboration of nitriles and the proposed mechanism.
Scheme 10: Myrtanylborane-catalysed asymmetric reduction of propargylic ketones and the proposed mechanism.
Scheme 11: H-B-9-BBN-catalysed C–F esterification of alkyl fluorides and the proposed mechanism.
Scheme 12: H-B-9-BBN-catalysed 1,4-hydroboration of enones and the proposed mechanism.
Scheme 13: Boric acid-promoted reduction of esters, lactones, and carbonates and the proposed mechanism.
Scheme 14: H-B-9-BBN-catalysed reductive aldol-type reaction and the proposed mechanism.
Scheme 15: H-B-9-BBN-catalysed diastereoselective allylation of ketones and the Ph-BBD-catalysed enantioselect...
Scheme 16: H-B-9-BBN-catalysed C–F arylation of benzyl fluorides and the proposed mechanism.
Scheme 17: Borane-catalysed S‒H borylation of thiols and the proposed mechanism.
Scheme 18: Borane-catalysed hydroalumination of alkenes and allenes.
Scheme 19: a) Aluminium-catalysed hydroboration of alkynes and example catalysts. b) Deprotonation mechanistic...
Scheme 20: Aluminium-catalysed hydroboration of alkenes and the proposed mechanism.
Scheme 21: Aluminium-catalysed C–H borylation of terminal alkynes and the proposed mechanism.
Scheme 22: Aluminium-catalysed dehydrocoupling of amines, alcohols, and thiols with H-B-9-BBN or HBpin and the...
Scheme 23: Aluminium-catalysed hydroboration of unsaturated compounds and the general reaction mechanism.
Scheme 24: a) Gallium-catalysed asymmetric hydroboration of ketones and the proposed mechanism. b) Gallium-cat...
Scheme 25: Gallium(I)-catalysed allylation/propargylation of acetals and aminals and the proposed mechanism.
Scheme 26: Indium(I)-catalysed allylation/propargylation of acetals, aminals, and alkyl ethers.
Scheme 27: Iron–indium cocatalysed double hydroboration of nitriles and the proposed mechanism.
Figure 1: a) The number of reports for a given group 13 exchange in catalysis. b) Average free energy barrier...
Strategies to access the [5-8] bicyclic core encountered in the sesquiterpene, diterpene and sesterterpene series
- Cécile Alleman,
- Charlène Gadais,
- Laurent Legentil and
- François-Hugues Porée
Beilstein J. Org. Chem. 2023, 19, 245–281, doi:10.3762/bjoc.19.23
- rhodium-based catalysts and 5% of [Rh(CO)2Cl]2 were found to be the best catalyst loading (28% yield). The addition of a silver additive, to make the reaction quicker and to remove a CO ligand, appeared to be useless in this case, with no reaction, and the use of 50% dppp as ligand allowed the formation
Graphical Abstract
Figure 1: Examples of terpenes containing a bicyclo[3.6.0]undecane motif.
Figure 2: Commercially available first and second generation Grubbs and Hoveyda–Grubbs catalysts.
Figure 3: Examples of strategies to access the fusicoccan and ophiobolin tricyclic core structure by RCM.
Scheme 1: Synthesis of bicyclic core structure 12 of ophiobolin M (13) and cycloaraneosene (14).
Scheme 2: Synthesis of the core structure 21 of ophiobolins and fusicoccanes.
Scheme 3: Ring-closing metathesis attempts starting from thioester 22.
Scheme 4: Total synthesis of ent-fusicoauritone (28).
Figure 4: General structure of ophiobolins and congeners.
Scheme 5: Total synthesis of (+)-ophiobolin A (8).
Scheme 6: Investigation of RCM for the synthesis of ophiobolin A (8). Path A) RCM with TBDPS-protected alcoho...
Scheme 7: Synthesis of the core structure of cotylenin A aglycon, cotylenol (50).
Scheme 8: Synthesis of tricyclic core structure of fusicoccans.
Scheme 9: Total synthesis of (−)-teubrevin G (59).
Scheme 10: Synthesis of the core skeleton 63 of the basmane family.
Scheme 11: Total synthesis of (±)-schindilactone A (68).
Scheme 12: Total synthesis of dactylol (72).
Scheme 13: Ring-closing metathesis for the total synthesis of (±)-asteriscanolide (2).
Scheme 14: Synthesis of the simplified skeleton of pleuromutilin (1).
Scheme 15: Total synthesis of (−)-nitidasin (93) using a ring-closing metathesis to construct the eight-member...
Scheme 16: Total synthesis of (±)-naupliolide (97).
Scheme 17: Synthesis of the A-B ring structure of fusicoccane (101).
Scheme 18: First attempts of TRCM of dienyne substrates.
Scheme 19: TRCM on optimized substrates towards the synthesis of ophiobolin A (8).
Scheme 20: Tandem ring-closing metathesis for the synthesis of variecolin intermediates 114 and 115.
Scheme 21: Synthesis of poitediol (118) using the allylsilane ring-closing metathesis.
Scheme 22: Access to scaffold 122 by a NHK coupling reaction.
Scheme 23: Key step to construct the [5-8] bicyclooctanone core of aquatolide (4).
Scheme 24: Initial strategy to access aquatolide (4).
Scheme 25: Synthetic plan to cotylenin A (130).
Scheme 26: [5-8] Bicyclic structure of brachialactone (7) constructed by a Mizoroki–Heck reaction.
Scheme 27: Influence of the replacement of the allylic alcohol moiety.
Scheme 28: Formation of variecolin intermediate 140 through a SmI2-mediated Barbier-type reaction.
Scheme 29: SmI2-mediated ketyl addition. Pleuromutilin (1) eight-membered ring closure via C5–C14 bond formati...
Scheme 30: SmI2-mediated dialdehyde cyclization cascade of [5-8-6] pleuromutilin scaffold 149.
Scheme 31: A) Modular synthetic route to mutilin and pleuromutilin family members by Herzon’s group. B) Scaffo...
Scheme 32: Photocatalyzed oxidative ring expansion in pleuromutilin (1) total synthesis.
Scheme 33: Reductive radical cascade cyclization route towards (−)-6-epi-ophiobolin N (168).
Scheme 34: Reductive radical cascade cyclization route towards (+)-6-epi-ophiobolin A (173).
Scheme 35: Radical 8-endo-trig-cyclization of a xanthate precursor.
Figure 5: Structural representations of hypoestin A (177), albolic acid (178), and ceroplastol II (179) beari...
Scheme 36: Synthesis of the common [5-8-5] tricyclic intermediate of hypoestin A (177), albolic acid (178), an...
Scheme 37: Asymmetric synthesis of hypoestin A (177), albolic acid (178), and ceroplastol II (179).
Figure 6: Scope of the Pauson–Khand reaction.
Scheme 38: Nazarov cyclization revealing the fusicoauritone core structure 192.
Scheme 39: Synthesis of fusicoauritone (28) through Nazarov cyclization.
Scheme 40: (+)-Epoxydictymene (5) synthesis through a Nicholas cyclization followed by a Pauson–Khand reaction...
Scheme 41: Synthesis of aquatolide (4) by a Mukaiyama-type aldolisation.
Scheme 42: Tandem Wolff/Cope rearrangement furnishing the A-B bicyclic moiety 204 of variecolin.
Scheme 43: Asymmetric synthesis of the A-B bicyclic core 205 and 206 of variecolin.
Scheme 44: Formation of [5-8]-fused rings by cyclization under thermal activation.
Scheme 45: Construction of the [5-8-6] tricyclic core structure of variecolin (3) by Diels–Alder reaction.
Scheme 46: Synthesis of the [6-4-8-5]-tetracyclic skeleton by palladium-mediated cyclization.
Scheme 47: Access to the [5-8] bicyclic core structure of asteriscanolide (227) through rhodium-catalyzed cycl...
Scheme 48: Total syntheses of asterisca-3(15),6-diene (230) and asteriscanolide (2) with a Rh-catalyzed cycliz...
Scheme 49: Photocyclization of 2-pyridones to access the [5-8-5] backbone of fusicoccanes.
Scheme 50: Total synthesis of (+)-asteriscunolide D (245) and (+)-aquatolide (4) through photocyclization.
Scheme 51: Biocatalysis pathway to construct the [5-8-5] tricyclic scaffold of brassicicenes.
Scheme 52: Influence of the CotB2 mutant over the cyclization’s outcome of GGDP.
Germacrene B – a central intermediate in sesquiterpene biosynthesis
- Houchao Xu and
- Jeroen S. Dickschat
Beilstein J. Org. Chem. 2023, 19, 186–203, doi:10.3762/bjoc.19.18
- -workers [19], through a sequence of reduction to the alcohol, acetylation and reduction with lithium in ammonia (Scheme 3A) [20], and its structure was unambiguously assigned by X-ray crystallography of a silver nitrate adduct [21]. From natural sources, the compound was first obtained from Humulus
Graphical Abstract
Scheme 1: Possible cyclisation modes of FPP.
Scheme 2: Structures of germacrene B (1), germacrene A (2) and hedycaryol (3).
Scheme 3: The chemistry of germacrene B (1). A) Synthesis from germacrone (4), B) the four conformers of 1 es...
Scheme 4: The chemistry of germacrene B (1). A) Cyclisation of 1 to 9 and 10 upon treatment with alumina, B) ...
Scheme 5: Possible cyclisation reactions upon reprotonation of 1. A) Cyclisations to eudesmane sesquiterpenes...
Scheme 6: Cyclisation modes for 1 to the eudesmane skeleton. A) The reprotonation of 1 at C-1 potentially lea...
Scheme 7: The sesquiterpenes derived from cation I1. WMR = Wagner–Meerwein rearrangement.
Scheme 8: The sesquiterpenes derived from cation I1. A) Pyrolysis of 23 to yield 9 and 10, B) deprotonation–r...
Scheme 9: The sesquiterpenes derived from cation I1. A) Acid-catalysed conversion of 18 into 26, B) conversio...
Scheme 10: The sesquiterpenes derived from cation I1. A) Formation of 20 by pyrolysis of 33, B) acid-catalysed...
Scheme 11: The sesquiterpenes derived from cation I2. WMR = Wagner–Meerwein rearrangement.
Scheme 12: The sesquiterpenes derived from cation I2. A) Acid catalysed conversion of 41 into 38, B) dehydrati...
Scheme 13: The sesquiterpenes derived from cation I3. WMR = Wagner–Meerwein rearrangement.
Scheme 14: Cyclisation modes for 1 to the guaiane skeleton. A) The reprotonation of 1 at C-4 potentially leads...
Scheme 15: The sesquiterpenes derived from cations K1, K2 and K4. A) Mechanisms of formation for compounds 53–...
Scheme 16: The sesquiterpenes derived from cations L1–L4. A) Mechanisms of formation for compounds 54, 56, 59 ...
Catalytic aza-Nazarov cyclization reactions to access α-methylene-γ-lactam heterocycles
- Bilge Banu Yagci,
- Selin Ezgi Donmez,
- Onur Şahin and
- Yunus Emre Türkmen
Beilstein J. Org. Chem. 2023, 19, 66–77, doi:10.3762/bjoc.19.6
- the synthesis of tricyclic α-methylene-γ-lactams 7 as single diastereomers and in good to high yields through the use of a catalytic amount of AgOTf (silver trifluoromethanesulfonate) as an anion-exchange agent (Scheme 1d) [35]. In this transformation, treatment of 3,4-dihydroisoquinolines 5 with acyl
Graphical Abstract
Scheme 1: Examples of aza-Nazarov reactions.
Scheme 2: Aza-Nazarov cyclization on gram scale.
Scheme 3: Scope of the aza-Nazarov cyclization with acyclic imines. aThe syntheses of aza-Nazarov products 19b...
Figure 1: X-ray crystal structure of compound 19l.
Scheme 4: Proposed mechanism for the formation of diastereomers 19 and 22.
Scheme 5: Preparation of acyl chloride 23.
Scheme 6: Aza-Nazarov reaction tested using β-TMS-substituted acyl chloride 23.
Scheme 7: Hydrolysis of N-acyliminium intermediates.
Scheme 8: (a) Two possible pathways for the formation of 7 and (b) investigation of the reaction between imin...
Scheme 9: (a) Preparation of acyl chlorides 6ba and 6bb in diastereomerically pure forms, (b) aza-Nazarov cyc...
Formal total synthesis of macarpine via a Au(I)-catalyzed 6-endo-dig cycloisomerization strategy
- Jiayue Fu,
- Bingbing Li,
- Zefang Zhou,
- Maosheng Cheng,
- Lu Yang and
- Yongxiang Liu
Beilstein J. Org. Chem. 2022, 18, 1589–1595, doi:10.3762/bjoc.18.169
- ) itself failed to catalyze the cycloisomerization (Table 1, entry 1). Evaluation of a number of silver salts illustrated that silver hexafluoroantimonate (AgSbF6) was the optimal additive to activate the gold catalyst (Table 1, entries 2, 3, and 7). Screening of the other ligands of Au(I) catalysts
- ). The Au(I)-catalyzed cycloisomerization reaction of substrate 10 occurred under the catalysis of 5 mol % [1,3-bis(2,6-diisopropylphenyl)imidazol-2-ylidene]gold(I) chloride (IPrAuCl) and 5 mol % silver hexafluoroantimonate (AgSbF6) [25][26] in anhydrous DCM at room temperature for 2 h forming a benzene
Graphical Abstract
Scheme 1: Classification of benzo[c]phenanthridine alkaloids.
Scheme 2: Representative synthetic strategies for macarpine (1).
Scheme 3: Retrosynthetic analysis of marcarpine precursor 12 for a partial synthesis.
Scheme 4: Syntheses of precursors 5 and 8.
Scheme 5: Synthesis of enol silyl ether 10.
Scheme 6: Formal total synthesis of macarpine (1).
Design, synthesis, and evaluation of chiral thiophosphorus acids as organocatalysts
- Karen R. Winters and
- Jean-Luc Montchamp
Beilstein J. Org. Chem. 2022, 18, 1471–1478, doi:10.3762/bjoc.18.154
- based on silver either gave a complex mixture or unreacted starting material. Phosphonate 8 was converted into the corresponding thiophosphonate 9 in moderate yield using Lawesson's reagent. Cleavage of the methyl ester was easily accomplished in quantitative yield, producing racemic tryptophol CPA 1
- -catalyzed hydrophosphinylation [45]. The key heterocyclization of 11 into 12 was accomplished using silver-promoted homolytic aromatic substitution [46], which was superior to our own manganese methodology (43% yield) [36]. Copper-catalyzed arylation [34] of 12 with iodobenzene and 4-nitroiodobenzene gave
Graphical Abstract
Figure 1: Chiral phosphorus acids (CPAs) derived from BINOL, VAPOL, and SPINOL. R = H, Ph, 4-PhC6H4-, 4-β-nap...
Scheme 1: The thiolic/thionic tautomeric equilibrium in thiophosphorus acids.
Figure 2: Project strategy and requirements for C1-symmetrical CPAs.
Figure 3: BINOL CPA and C1-symmetrical CPA targets 1–4.
Scheme 2: Synthesis of tryptophol-derived thiophosphorus acid 1.
Scheme 3: Synthesis of indole-derived thiophosphorus acid 2.
Scheme 4: Synthesis of N-biphenyl-DOPO CPA 4.
Scheme 5: Transfer hydrogenation of 2-phenylquinoline and transition-state proposed by Guinchard and coworker...
Preparation of an advanced intermediate for the synthesis of leustroducsins and phoslactomycins by heterocycloaddition
- Anaïs Rousseau,
- Guillaume Vincent and
- Cyrille Kouklovsky
Beilstein J. Org. Chem. 2022, 18, 1385–1395, doi:10.3762/bjoc.18.143
- groups. Several conditions were tested: silver oxide on celite [33] failed to give any conversion. PCC with sodium acetate [34] gave only traces of the target lactone 25. However, the use of the Jones’ reagent gave reproducible yields of 25, together with the deprotected alcohol 26. Under optimized
Graphical Abstract
Figure 1: Structures of leustroducsins and phoslactomycins.
Figure 2: Synthetic strategy for the leustroducins and phoslactomycins.
Figure 3: strategy for the synthesis of central fragment 4: nitroso Diels–Alder reaction.
Scheme 1: A highly regio-and stereoselective nitroso Diels–Alder cycloaddition between Wightman’s reagent 6 a...
Scheme 2: Hydrolysis of enol phosphate in the unprotected cycloadduct.
Scheme 3: Attempts for hydrolysis of the enol phosphate under basic conditions.
Scheme 4: Cleavage of enol phosphate with Red-Al.
Scheme 5: Synthesis of the protected central fragment 11b.
Scheme 6: Synthesis and derivatization of the lactone fragment.
Scheme 7: Coupling reaction between alkyne 19 and ketone 11b.
Scheme 8: Coupling reaction between vinyl iodide 20 and ketone 11b.
Scheme 9: Oxidation of the acetal to the lactone.
Enantioselective total synthesis of putative dihydrorosefuran, a monoterpene with an unique 2,5-dihydrofuran structure
- Irene Torres-García,
- Josefa L. López-Martínez,
- Rocío López-Domene,
- Manuel Muñoz-Dorado,
- Ignacio Rodríguez-García and
- Miriam Álvarez-Corral
Beilstein J. Org. Chem. 2022, 18, 1264–1269, doi:10.3762/bjoc.18.132
- , 3H) ppm; 13C{1H} NMR (75 MHz, CDCl3, DEPT) δ 206.0 (C), 177.0 (C), 98.0 (C), 80.4 (CH), 77.5 (CH2), 28.5 (CH2), 26.1 (CH2), 15.0 (CH3) ppm; HRMS–ESI (Q-TOF, m/z): [M + H]+ calcd for C8H11O2,139.0759; found, 139.0782. Silver(I)-promoted cyclization of ethyl 4-hydroxy-5-methylhepta-5,6-dienoate (3) A
Graphical Abstract
Scheme 1: Retrosynthetic scheme of the target molecule 1.
Scheme 2: Synthesis of dihydrofuran-monoterpenoid 1. a) i. O3, −78 °C; ii. PPh3, rt, 76%; b) 1-bromobut-2-yne...
Scheme 3: Racemic resolution of allenol 3 and synthesis of derivatives. a) Lipase AK, vinyl acetate, t-BuOMe,...
Scope of tetrazolo[1,5-a]quinoxalines in CuAAC reactions for the synthesis of triazoloquinoxalines, imidazoloquinoxalines, and rhenium complexes thereof
- Laura Holzhauer,
- Chloé Liagre,
- Olaf Fuhr,
- Nicole Jung and
- Stefan Bräse
Beilstein J. Org. Chem. 2022, 18, 1088–1099, doi:10.3762/bjoc.18.111
- ). Improving this route provides an alternative to the literature-known method [11] that requires both a special porphyrin complex and glovebox conditions. Using neither silver(I) triflate nor copper(I) iodide yielded the imidazole product, indicating that the use of copper(I) triflate is crucial for the
Graphical Abstract
Scheme 1: Reactions of tetrazoloquinoxalines 1 to 1,2,3-triazoloquinoxalines 3 via CuAAC and denitrogenative ...
Scheme 2: Synthesis of tetrazolo[1,5-a]quinoxalines. Reaction conditions: (a) 9, THF or 4 M HCl, 70–110 °C, 2...
Scheme 3: Synthesis of 1,2,3-triazole-substituted quinoxalines via CuAAC from tetrazolo[1,5-a]quinoxaline (11a...
Scheme 4: Mechanism of CuAAC vs denitrogenative annulation.
Scheme 5: Synthesis of bis(tetrazolo)[1,5-a:5',1'-c]quinoxaline (24) and conversion to triazoloimidazoquinoxa...
Scheme 6: Synthesis of rhenium tricarbonyl complexes 27a–d and ORTEP diagrams of the resulting molecular stru...
Scheme 7: Synthesis of rhenium tricarbonyl complex 29 and ORTEP diagram of the resulting molecular structure ...
Scheme 8: Synthesis of a TIQ rhenium complex and ORTEP diagram of the obtained product 30 with the thermal el...
Figure 1: UV–vis absorption spectra of the obtained metal complexes (18 µM solutions) in acetonitrile at 20 °...
Figure 2: Cyclic voltammetry traces for rhenium complexes 27a–d, 29 and 30: 0.5 mM in MeCN solution with 0.1 ...
First example of organocatalysis by cathodic N-heterocyclic carbene generation and accumulation using a divided electrochemical flow cell
- Daniele Rocco,
- Ana A. Folgueiras-Amador,
- Richard C. D. Brown and
- Marta Feroci
Beilstein J. Org. Chem. 2022, 18, 979–990, doi:10.3762/bjoc.18.98
- (Table 1, entry 4). However, using a silver electrode the corresponding thione was not observed (Table 1, entry 3) [37]. In view of the acidic character of the perfluorosulfonic acid Nafion® membrane, and possible NHC protonation to form the imidazolium cation, the Nafion® membrane was pretreated with an
Graphical Abstract
Scheme 1: Electrochemical generation of NHC.
Scheme 2: Transformation of electrochemically generated NHC into the corresponding thione by its reaction wit...
Scheme 3: Umpolung of the aldehyde carbonyl carbon atom. Formation of the Breslow intermediate using NHCs.
Figure 1: Schematic representation of a plane-parallel plate flow electrochemical reactor.
Figure 2: C/PVDF anode before (A) and after (B) the first experiment (Table 1, entry 1).
Scheme 4: Electrogenerated NHC-catalyzed self-annulation of cinnamaldehyde.
Scheme 5: Byproduct obtained from the reaction between methanol and the Breslow intermediate.
Figure 3: Expanded view of the electrochemical cell components: (a) Aluminium end plates; (b) insulating PTFE...
Complementarity of solution and solid state mechanochemical reaction conditions demonstrated by 1,2-debromination of tricyclic imides
- Petar Štrbac and
- Davor Margetić
Beilstein J. Org. Chem. 2022, 18, 746–753, doi:10.3762/bjoc.18.75
- , a synthetic methodology for the preparation of 1–3 was developed by Warrener and co-workers by a Zn/Ag couple debromination [13][14][15]. However, this methodology has some disadvantages, such as tedious preparation of the catalyst, the use of dry solvent and expensive silver acetate as well as side
- usual procedure from Zn and silver acetate. Several simplifications of the Zn/Ag couple preparation were tested and showed that simple milling with Zn dust and Ag dust or wire can be also applied (Table 1, entries 5–8) [21]. Further improvement in the procedure was the replacement of the Ag dust with Cu
Graphical Abstract
Figure 1: Highly reactive dienophiles.
Figure 2: Dibromide substrates and product 12.
Scheme 1: Mechanochemical reaction of 10 with anthracene.
Figure 3: Scope of the Zn/Cu reaction with dibromide 10 (dienes are colored in red).
Scheme 2: Mechanochemical reaction of 11 with furan.
Scheme 3: Reactivity of bicyclo[2.2.2] dibromide 42 with dienes.
Menadione: a platform and a target to valuable compounds synthesis
- Acácio S. de Souza,
- Ruan Carlos B. Ribeiro,
- Dora C. S. Costa,
- Fernanda P. Pauli,
- David R. Pinho,
- Matheus G. de Moraes,
- Fernando de C. da Silva,
- Luana da S. M. Forezi and
- Vitor F. Ferreira
Beilstein J. Org. Chem. 2022, 18, 381–419, doi:10.3762/bjoc.18.43
- useful alkylation approach is the Kochi–Anderson method [76] (or also known as Jacobsen–Torssell method [77][78]), via oxidative decarboxylation, where the quinone reacts with a carboxylic acid in the presence of silver(I) nitrate and ammonium or potassium peroxydisulfate. Nucleophilic free radicals are
- -workers [79]. 1,4-Naphthoquinone (1) was treated with acetic acid in the presence of ammonium persulfate, as oxidizing agent, and silver(I) catalysis for only 1 hour, furnishing menadione (10) in 47% yield (Scheme 1). After this pioneering work, some adaptations were reported. As an example, Liu and co
- -dimethoxyarenes is another valid synthetic approach to achieve 1,4-quinones, with the oxidative demethylation of 2-methyl-1,4-dimethoxynaphthalene (19) can be used to synthesize menadione (10). The oxidizing agents most commonly used in oxidative demethylation are cerium(IV) ammonium nitrate (CAN), and silver(II
Graphical Abstract
Figure 1: Natural bioactive naphthoquinones.
Figure 2: Chemical structures of vitamins K.
Figure 3: Redox cycle of menadione.
Scheme 1: Selected approaches for menadione synthesis using silver(I) as a catalyst.
Scheme 2: Methylation approaches for the preparation of menadione from 1,4-naphthoquinone using tert-butyl hy...
Scheme 3: Methylation approach of 1,4-naphthoquinone using i) rhodium complexes/methylboronic acid and ii) bi...
Scheme 4: Synthesis of menadione (10) from itaconic acid.
Scheme 5: Menadione synthesis via Diels–Alder reaction.
Scheme 6: Synthesis of menadione (10) using p-cresol as a synthetic precursor.
Scheme 7: Synthesis of menadione (10) via demethoxycarbonylating annulation of methyl methacrylate.
Scheme 8: Furan 34 used as a diene in a Diels–Alder reaction for the synthesis of menadione (10).
Scheme 9: o-Toluidine as a dienophile in a Diels–Alder reaction for the synthesis of menadione (10).
Scheme 10: Representation of electrochemical synthesis of menadione.
Figure 4: Reaction sites and reaction types of menadione as substrate.
Scheme 11: DBU-catalyzed epoxidation of menadione (10).
Scheme 12: Phase-transfer catalysis for the epoxidation of menadione.
Scheme 13: Menadione epoxidation using a hydroperoxide derived from (+)-norcamphor.
Scheme 14: Enantioselective Diels–Alder reaction for the synthesis of asymmetric quinone 50 catalyzed by a chi...
Scheme 15: Optimized reaction conditions for the synthesis of anthra[9,1-bc]pyranone.
Scheme 16: Synthesis of anthra[9,1-bc]furanone, anthra[9,1-bc]pyridine, and anthra[9,1-bc]pyrrole derivatives.
Scheme 17: Synthesis of derivatives employing protected trienes.
Scheme 18: Synthesis of cyclobutene derivatives of menadione.
Scheme 19: Menadione reduction reactions using sodium hydrosulfite.
Scheme 20: Green methodology for menadiol synthesis and pegylation.
Scheme 21: Menadione reduction by 5,6-O-isopropylidene-ʟ-ascorbic acid under UV light irradiation.
Scheme 22: Selected approaches of menadione hydroacetylation to diacetylated menadiol.
Scheme 23: Thiele–Winter reaction catalyzed by Bi(OTf)3.
Scheme 24: Carbonyl condensation of menadione using resorcinol and a hydrazone derivative.
Scheme 25: Condensation reaction of menadione with thiosemicarbazide.
Scheme 26: Condensation reaction of menadione with acylhydrazides.
Scheme 27: Menadione derivatives functionalized with organochalcogens.
Scheme 28: Synthesis of selenium-menadione conjugates derived from chloromethylated menadione 84.
Scheme 29: Menadione alkylation by the Kochi–Anderson method.
Scheme 30: Menadione alkylation by diacids.
Scheme 31: Menadione alkylation by heterocycles-substituted carboxylic acids.
Scheme 32: Menadione alkylation by bromoalkyl-substituted carboxylic acids.
Scheme 33: Menadione alkylation by complex carboxylic acids.
Scheme 34: Kochi–Anderson method variations for the menadione alkylation via oxidative decarboxylation of carb...
Scheme 35: Copper-catalyzed menadione alkylation via free radicals.
Scheme 36: Nickel-catalyzed menadione cyanoalkylation.
Scheme 37: Iron-catalyzed alkylation of menadione.
Scheme 38: Selected approaches to menadione alkylation.
Scheme 39: Menadione acylation by photo-Friedel–Crafts acylation reported by Waske and co-workers.
Scheme 40: Menadione acylation by Westwood procedure.
Scheme 41: Synthesis of 3-benzoylmenadione via metal-free TBAI/TBHP system.
Scheme 42: Michael-type addition of amines to menadione reported by Kallmayer.
Scheme 43: Synthesis of amino-menadione derivatives using polyalkylamines.
Scheme 44: Selected examples for the synthesis of different amino-substituted menadione derivatives.
Scheme 45: Selected examples of Michael-type addition of complex amines to menadione (10).
Scheme 46: Addition of different natural α-amino acids to menadione.
Scheme 47: Michael-type addition of amines to menadione using silica-supported perchloric acid.
Scheme 48: Indolylnaphthoquinone or indolylnaphthalene-1,4-diol synthesis reported by Yadav et al.
Scheme 49: Indolylnaphthoquinone synthesis reported by Tanoue and co-workers.
Scheme 50: Indolylnaphthoquinone synthesis from menadione by Escobeto-González and co-workers.
Scheme 51: Synthesis of menadione analogues functionalized with thiols.
Scheme 52: Synthesis of menadione-derived symmetrical derivatives through reaction with dithiols.
Scheme 53: Mercaptoalkyl acids as nucleophiles in Michael-type addition reaction to menadione.
Scheme 54: Reactions of menadione (10) with cysteine derivatives for the synthesis of quinoproteins.
Scheme 55: Synthesis of menadione-glutathione conjugate 152 by Michael-type addition.
Synthesis of piperidine and pyrrolidine derivatives by electroreductive cyclization of imine with terminal dihaloalkanes in a flow microreactor
- Yuki Naito,
- Naoki Shida and
- Mahito Atobe
Beilstein J. Org. Chem. 2022, 18, 350–359, doi:10.3762/bjoc.18.39
- of the cathode material on the yield of 3a using three different cathode materials: platinum (Pt), glassy carbon (GC), and silver (Ag). As shown in Table 1, the yield of 3a was higher using GC than that of the other cathode materials. The yield of the hydromonomeric product 4 was also highest when GC
Graphical Abstract
Figure 1: Piperidine and pyrrolidine rings in biologically active compounds.
Scheme 1: Conventional synthetic routes for piperidine derivatives.
Scheme 2: Synthesis of 1,2-diphenylpiperidine (3a) by the electroreductive cyclization mechanism.
Figure 2: Schematic diagram of the electroreductive cyclization for the synthesis of 1,2-diphenylpiperidine (...
Figure 3: Yield of 3a for each fraction sample in the continuous flow reductive cyclization.
Organocatalytic asymmetric nitroso aldol reaction of α-substituted malonamates
- Ekta Gupta,
- Narendra Kumar Vaishanv,
- Sandeep Kumar,
- Raja Krishnan Purshottam,
- Ruchir Kant and
- Kishor Mohanan
Beilstein J. Org. Chem. 2022, 18, 217–224, doi:10.3762/bjoc.18.25
- using a silver-BINAP catalyst combination [25]. Later, the same group could successfully tune the catalytic system to control the regioselectivity in the addition of metal enolate to nitrosoarenes to achieve an α-hydroxyamination [26]. Since then, several groups have shown the use of metal-catalyzed
Graphical Abstract
Scheme 1: Catalytic asymmetric nitroso aldol reaction.
Scheme 2: Variation of the amide moiety of malonamates. General conditions: 1 (0.20 mmol), 2a (0.24 mmol), 3a...
Figure 1: ORTEP diagram drawn with 30% ellipsoid probability for non-H atoms of the crystal structure of chir...
Scheme 3: Variation of ester moiety of malonamates and nitrosoarenes. General conditions: 1 (0.20 mmol), 2a (...
Scheme 4: Synthetic transformation.
Figure 2: Proposed transition state for the nitroso aldol reaction.
Study on the interactions between melamine-cored Schiff bases with cucurbit[n]urils of different sizes and its application in detecting silver ions
- Jun-Xian Gou,
- Yang Luo,
- Xi-Nan Yang,
- Wei Zhang,
- Ji-Hong Lu,
- Zhu Tao and
- Xin Xiao
Beilstein J. Org. Chem. 2021, 17, 2950–2958, doi:10.3762/bjoc.17.204
- host–guest interactions. Among them, Q[7]-TBT is selected as a UV detector for the detection of silver ions (Ag+). This work makes full use of the characteristics of each cucurbituril and melamine-cored Schiff base to construct a series of complexes and these are applied to metal detection. Keywords
- : cucurbiturils; melamine; Schiff base; silver ion; Introduction Schiff bases [1] are usually synthesized by the condensation of amines and active carbonyl compounds, endowing them both nitrogen and oxygen donor atoms [2][3][4][5]. Schiff bases are not only easy to coordinate with various transition metal ions
- supermolecule polymer with TBT due to its larger cavity. Since Q[7] and TBT form a host–guest complex, the carboxyl group at the end of TBT and the carbonyl group of the Q[7] still have a strong ability to coordinate with metals. Therefore, Q[7]-TBT is selected for the detection of silver ions (Ag+) [32][33
Graphical Abstract
Scheme 1: The Structures of Q[7], Q[8], TMeQ[6], and TBT.
Figure 1: The 1H NMR titration of TBT (1 mM) with an increasing amount of TMeQ[6] from 0 (i), 0.1 (ii), 0.2 (...
Figure 2: The 1H NMR titration of TBT (1 mM) with an increasing amount of Q[7] from 0 (i), 0.1 (ii), 0.5 (iii...
Figure 3: The UV–vis spectra (a) of TBT (20 μM) with an increasing amount of Q[7] from 0.0 to 4.0 equiv; the ...
Figure 4: The UV–vis spectra (a) of TBT (20 μM) with an increasing amount of Q[8] from 0.0 to 4.0 equiv and t...
Figure 5: The UV–vis spectra (a) of Q[7]-TBT (3:1, 20 μM) affected by Mn+ (50 equivalents); histogram of (b) ...
Figure 6: The UV–vis spectra (a) of Q[7]-TBT (20 μM) with an increasing amount of Ag+ from 0.0 to 2.0 equiv; ...
Scheme 2: The synthesis of TBT.
Iron-catalyzed domino coupling reactions of π-systems
- Austin Pounder and
- William Tam
Beilstein J. Org. Chem. 2021, 17, 2848–2893, doi:10.3762/bjoc.17.196
Graphical Abstract
Figure 1: Price comparison among iron and other transition metals used in catalysis.
Scheme 1: Typical modes of C–C bond formation.
Scheme 2: The components of an iron-catalyzed domino reaction.
Scheme 3: Iron-catalyzed tandem cyclization and cross-coupling reactions of iodoalkanes 1 with aryl Grignard ...
Scheme 4: Three component iron-catalyzed dicarbofunctionalization of vinyl cyclopropanes 14.
Scheme 5: Three-component iron-catalyzed dicarbofunctionalization of alkenes 21.
Scheme 6: Double carbomagnesiation of internal alkynes 31 with alkyl Grignard reagents 32.
Scheme 7: Iron-catalyzed cycloisomerization/cross-coupling of enyne derivatives 35 with alkyl Grignard reagen...
Scheme 8: Iron-catalyzed spirocyclization/cross-coupling cascade.
Scheme 9: Iron-catalyzed alkenylboration of alkenes 50.
Scheme 10: N-Alkyl–N-aryl acrylamide 60 CDC cyclization with C(sp3)–H bonds adjacent to a heteroatom.
Scheme 11: 1,2-Carboacylation of activated alkenes 60 with aldehydes 65 and alcohols 67.
Scheme 12: Iron-catalyzed dicarbonylation of activated alkenes 68 with alcohols 67.
Scheme 13: Iron-catalyzed cyanoalkylation/radical dearomatization of acrylamides 75.
Scheme 14: Synergistic photoredox/iron-catalyzed 1,2-dialkylation of alkenes 82 with common alkanes 83 and 1,3...
Scheme 15: Iron-catalyzed oxidative coupling/cyclization of phenol derivatives 86 and alkenes 87.
Scheme 16: Iron-catalyzed carbosulfonylation of activated alkenes 60.
Scheme 17: Iron-catalyzed oxidative spirocyclization of N-arylpropiolamides 91 with silanes 92 and tert-butyl ...
Scheme 18: Iron-catalyzed free radical cascade difunctionalization of unsaturated benzamides 94 with silanes 92...
Scheme 19: Iron-catalyzed cyclization of olefinic dicarbonyl compounds 97 and 100 with C(sp3)–H bonds.
Scheme 20: Radical difunctionalization of o-vinylanilides 102 with ketones and esters 103.
Scheme 21: Dehydrogenative 1,2-carboamination of alkenes 82 with alkyl nitriles 76 and amines 105.
Scheme 22: Iron-catalyzed intermolecular 1,2-difunctionalization of conjugated alkenes 107 with silanes 92 and...
Scheme 23: Four-component radical difunctionalization of chemically distinct alkenes 114/115 with aldehydes 65...
Scheme 24: Iron-catalyzed carbocarbonylation of activated alkenes 60 with carbazates 117.
Scheme 25: Iron-catalyzed radical 6-endo cyclization of dienes 119 with carbazates 117.
Scheme 26: Iron-catalyzed decarboxylative synthesis of functionalized oxindoles 130 with tert-butyl peresters ...
Scheme 27: Iron‑catalyzed decarboxylative alkylation/cyclization of cinnamamides 131/134.
Scheme 28: Iron-catalyzed carbochloromethylation of activated alkenes 60.
Scheme 29: Iron-catalyzed trifluoromethylation of dienes 142.
Scheme 30: Iron-catalyzed, silver-mediated arylalkylation of conjugated alkenes 115.
Scheme 31: Iron-catalyzed three-component carboazidation of conjugated alkenes 115 with alkanes 101/139b and t...
Scheme 32: Iron-catalyzed carboazidation of alkenes 82 and alkynes 160 with iodoalkanes 20 and trimethylsilyl ...
Scheme 33: Iron-catalyzed asymmetric carboazidation of styrene derivatives 115.
Scheme 34: Iron-catalyzed carboamination of conjugated alkenes 115 with alkyl diacyl peroxides 163 and acetoni...
Scheme 35: Iron-catalyzed carboamination using oxime esters 165 and arenes 166.
Scheme 36: Iron-catalyzed iminyl radical-triggered [5 + 2] and [5 + 1] annulation reactions with oxime esters ...
Scheme 37: Iron-catalyzed decarboxylative alkyl etherification of alkenes 108 with alcohols 67 and aliphatic a...
Scheme 38: Iron-catalyzed inter-/intramolecular alkylative cyclization of carboxylic acid and alcohol-tethered...
Scheme 39: Iron-catalyzed intermolecular trifluoromethyl-acyloxylation of styrene derivatives 115.
Scheme 40: Iron-catalyzed carboiodination of terminal alkenes and alkynes 180.
Scheme 41: Copper/iron-cocatalyzed cascade perfluoroalkylation/cyclization of 1,6-enynes 183/185.
Scheme 42: Iron-catalyzed stereoselective carbosilylation of internal alkynes 187.
Scheme 43: Synergistic photoredox/iron catalyzed difluoroalkylation–thiolation of alkenes 82.
Scheme 44: Iron-catalyzed three-component aminoazidation of alkenes 82.
Scheme 45: Iron-catalyzed intra-/intermolecular aminoazidation of alkenes 194.
Scheme 46: Stereoselective iron-catalyzed oxyazidation of enamides 196 using hypervalent iodine reagents 197.
Scheme 47: Iron-catalyzed aminooxygenation for the synthesis of unprotected amino alcohols 200.
Scheme 48: Iron-catalyzed intramolecular aminofluorination of alkenes 209.
Scheme 49: Iron-catalyzed intramolecular aminochlorination and aminobromination of alkenes 209.
Scheme 50: Iron-catalyzed intermolecular aminofluorination of alkenes 82.
Scheme 51: Iron-catalyzed aminochlorination of alkenes 82.
Scheme 52: Iron-catalyzed phosphinoylazidation of alkenes 108.
Scheme 53: Synergistic photoredox/iron-catalyzed three-component aminoselenation of trisubstituted alkenes 82.
Host–guest interaction and properties of cucurbit[8]uril with chloramphenicol
- Lin Zhang,
- Jun Zheng,
- Guangyan Luo,
- Xiaoyue Li,
- Yunqian Zhang,
- Zhu Tao and
- Qianjun Zhang
Beilstein J. Org. Chem. 2021, 17, 2832–2839, doi:10.3762/bjoc.17.194
- in water and has a bitter taste. Upon forming an inclusion complex with cyclodextrin, the solubility and bitter taste of CPE can be improved [4][5]. Ramesh Gannimani et al. [6] reported that the inclusion complex of cyclodextrin and CPE loaded silver nanoparticles possessed stronger antibacterial
Graphical Abstract
Figure 1: The structures of chloramphenicol (A) and cucurbit[n]urils (B).
Figure 2: (A) CPE and Q[8] structural model diagram, (B) interaction between CPE and Q[8], (C) CPE@Q[8] stack...
Figure 3: UV–vis absorption spectra of CPE with Q[8] in aqueous solution (A) or hydrochloric acid solution (C...
Figure 4: ITC data obtained for the binding of Q[8] with CPE in an aqueous solution at 25 °C.
Figure 5: 1H NMR spectra of CPE, CPE@Q[8] and Q[8] (VD2O/VDCl = 3:2).
Figure 6: IR spectra recorded for Q[8] (a), CPE (b), a physical mixture of Q[8] and CPE (c), and the CPE@Q[8]...
Figure 7: UV absorption intensity of CPE and CPE@Q[8] changes with time in the artificial gastrointestinal ju...
Figure 8: Release curve of CPE and CPE@Q[8] in artificial gastrointestinal juice (pH 1.2, pH 6.8).
Selective sulfonylation and isonitrilation of para-quinone methides employing TosMIC as a source of sulfonyl group or isonitrile group
- Chuanhua Qu,
- Run Huang,
- Yong Li,
- Tong Liu,
- Yuan Chen and
- Guiting Song
Beilstein J. Org. Chem. 2021, 17, 2822–2831, doi:10.3762/bjoc.17.193
- reaction without adding bases, and unexpectedly found Ag salts could catalyze the 1,6-conjugate addition of TosMIC (2a) and p-QM 1a to provide aryl(phenol)methane isonitrile 4a under base-free conditions (Table 1, entries 6–8). When the silver salt was removed from the reaction conditions, the reaction did
Graphical Abstract
Figure 1: Selected bioactive compounds.
Scheme 1: The chemistry of TosMIC in the reactions with olefins.
Scheme 2: ZnI2-catalyzed C–S-bond cleavage of TosMIC for the synthesis of diarylmethyl sulfones 3a–m. Reactio...
Scheme 3: Cases encountered by other p-QMs examinations.
Figure 2: Crystal structure of diarylmethyl sulfone 3e.
Scheme 4: DBU-catalyzed 1,6-conjugate addition for the synthesis of isonitrile diarylmethanes 4a–h. Reaction ...
Scheme 5: Synthetic applications of the synthesized compound 3b.
Scheme 6: Mechanistic studies and proposed mechanism.
Synthesis of highly substituted fluorenones via metal-free TBHP-promoted oxidative cyclization of 2-(aminomethyl)biphenyls. Application to the total synthesis of nobilone
- Ilya A. P. Jourjine,
- Lukas Zeisel,
- Jürgen Krauß and
- Franz Bracher
Beilstein J. Org. Chem. 2021, 17, 2668–2679, doi:10.3762/bjoc.17.181
- . Benzylamines and derivatives thereof have been described in literature to be susceptible to oxidation by diverse reagents (tritylium ion [40], silver [38] and cerium salts [41], peroxides [42][43][44] and persulfates [45], nitroxyls [46], hypervalent iodine compounds [39][47], or tetrahalomethanes [48]) to
Graphical Abstract
Scheme 1: Selected fluorenone-type natural products.
Scheme 2: Overview of published cyclization methodologies for the synthesis of fluorenones starting from func...
Scheme 3: Preliminary considerations for the oxidative cyclization of 2-(aminomethyl)biphenyls to fluorenones....
Scheme 4: Substrate scope and yields for oxidative cyclizations of N-methyl-2-(aminomethyl)biphenyls 9a–d bea...
Scheme 5: Substrate scope for the oxidative cyclization of 2-(aminomethyl)biphenyls. Conditions: a) Boc2O, NEt...
Scheme 6: Substrate scope for the oxidative cyclization of 2-(aminomethyl)biphenyls with main focus on protec...
Scheme 7: Total synthesis of nobilone (1d). Conditions: a) TBS-Cl, imidazole, DMF, 50 °C, 18 h; b) n-BuLi, B(...
Scheme 8: Proposed mechanism for the oxidative cyclization of amines 2a and 2b to fluorenone (3).
