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Search for "acylation reaction" in Full Text gives 35 result(s) in Beilstein Journal of Organic Chemistry.
Semisynthetic derivatives of massarilactone D with cytotoxic and nematicidal activities
- Rémy B. Teponno,
- Sara R. Noumeur and
- Marc Stadler
Beilstein J. Org. Chem. 2025, 21, 607–615, doi:10.3762/bjoc.21.48
- nematicidal activity with LD90 and LD50 of 100 and 12.5 µg/mL, respectively. Since the parent compound was not active, the present study supports the fact that the acylation reaction can improve bioactivities of some natural products. Keywords: acylation reaction; cytotoxic activity; massarilactone D
- ranging from 3.51 to 32.73 μM. Furthermore, compounds 7 and 8 displayed cytotoxicity against the L929 and KB3-1 cell lines with IC50 values ranging from 18.50 to 61.73 μM (Table 1). Even if compounds 4–6 were not active, the present investigation revealed that the acylation reaction can improve the
Graphical Abstract
Scheme 1: Preparation of massarilactone D derivatives 2–8. Reagents and reactions conditions: a) (CH3CH2)3N/D...
Cyclodextrin-based rotaxanes for polymer materials: challenge on simultaneous realization of inexpensive production and defined structures
- Yosuke Akae
Beilstein J. Org. Chem. 2024, 20, 3026–3049, doi:10.3762/bjoc.20.252
- 80 °C. Additionally, that for a single native α-CD molecule proceeded completely at 60 °C within 2.5 h. Thus, the reaction temperature was confirmed as the key to completing the acylation reaction, probably because of the huge steric hindrance of the densely packed hydroxy groups on the [3]rotaxane
Graphical Abstract
Figure 1: Overview of the CD-based rotaxane as a polymer material covered in this review.
Figure 2: CD structure.
Figure 3: Typical pathway for synthesizing CD-based rotaxanes.
Scheme 1: (A) Synthesis of α-CD-based [2]rotaxane via a metal–ligand complex. (B) Chemical structures of meth...
Scheme 2: Synthesis of α-CD-based polyrotaxane.
Scheme 3: Facile [3]rotaxane synthesis by the urea end-capping method.
Figure 4: (A) Single-crystal structure of α-CD-based [3]rotaxane 3 and PMα-CD-based [3]rotaxane 4. (B) Schema...
Figure 5: Structural control of CD-based [2]rotaxane via (A) light irradiation and (B) light irradiation and ...
Figure 6: Relationship among the plus–minus signs of ICD, the position of the guest molecule, and the axis of...
Figure 7: Structural control of CD-based rotaxane via (A) redox reaction and (B) in a solvent.
Scheme 4: (A) Synthesis of pseudopolyrotaxane bearing an ABA triblock copolymer as an axle. (B) Two synthetic...
Scheme 5: Slippage of size-complementary rotaxanes.
Figure 8: (A) Reversible formation of the CD-based [2]rotaxane. (B) Deslipping reaction of the CD-based size-...
Figure 9: (A) Chemical structures of [3]rotaxanes 2 and 3. (B) Schematic of the deslipping reaction of [3]rot...
Figure 10: (A) Modification of the axle ends of [3]rotaxane by (1) bromination and (2) the Suzuki coupling rea...
Figure 11: (A) ICD spectra of [3]rotaxanes bearing acylated (top) and conventional (bottom) CDs. (B) Schematic...
Figure 12: Synthesis of macromolecular[3]rotaxane via a size-complementary protocol.
Figure 13: Conjugated polymer insulated by (A) β-CD. (B) Triphenylamine-substituted β-CD.
Figure 14: Synthesis of the VSC and successive rotaxane-crosslinked polymer (RCP) preparation.
Figure 15: (A) Chemical structure of the [3]rotaxane crosslinker (RC). (B) Schematic of the synthesis and de-c...
Figure 16: (A) Random vinylation of the CD-based [3]rotaxane; (B) Schematic of the reaction between α-CD and m...
Figure 17: (A) Aggregation of CD-based [3]rotaxane. (B) Schematic of the plausible mechanism of the aggregatio...
Novel truxene-based dipyrromethanes (DPMs): synthesis, spectroscopic characterization and photophysical properties
- Shakeel Alvi and
- Rashid Ali
Beilstein J. Org. Chem. 2024, 20, 2163–2170, doi:10.3762/bjoc.20.186
- derivatives (12, 15, and 17) in controlled manner (with appropriate equivalents of acetyl chloride and aluminium chloride) using one-to-threefold Friedel–Crafts acylation reaction(s) at 0 °C to rt in dichloromethane (DCM) solvent (Scheme 1 and Scheme 2). Subsequent condensation of thus prepared acetylated
Graphical Abstract
Figure 1: Structures of some reported mono-, di- and tri-dipyrromethane derivatives [44-49].
Scheme 1: Synthesis of the mono-DPM-based truxene derivative 14.
Scheme 2: Synthesis of di- and tri-DPM-based truxene derivatives 16 and 18.
Figure 2: UV–vis absorption (left) and fluorescence spectra (right) recorded in chloroform.
Figure 3: Time-resolved fluorescence lifetime.
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
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...
Enolates ambushed – asymmetric tandem conjugate addition and subsequent enolate trapping with conventional and less traditional electrophiles
- Péter Kisszékelyi and
- Radovan Šebesta
Beilstein J. Org. Chem. 2023, 19, 593–634, doi:10.3762/bjoc.19.44
- compound. A similar tandem conjugate addition/acylation reaction sequence was utilized by the group of Jia in their work on the total synthesis of (−)-glaucocalyxin A [109]. Such diterpenoids, containing a 14-oxygenated bicyclo[3.2.1]octane ring system with several continuous stereocenters, are quite
Graphical Abstract
Scheme 1: General scheme depicting tandem reactions based on an asymmetric conjugate addition followed by an ...
Scheme 2: Cu-catalyzed tandem conjugate addition of R2Zn/aldol reaction with chiral acetals.
Scheme 3: Cu-catalyzed asymmetric desymmetrization of cyclopentene-1,3-diones using a tandem conjugate additi...
Scheme 4: Stereocontrolled assembly of dialkylzincs, cyclic enones, and sulfinylimines utilizing a Cu-catalyz...
Scheme 5: Cu-catalyzed tandem conjugate addition/Mannich reaction (A). Access to chiral isoindolinones and tr...
Scheme 6: Cu-catalyzed tandem conjugate addition/nitro-Mannich reaction (A) with syn–anti or syn–syn selectiv...
Figure 1: Various chiral ligands utilized for the tandem conjugate addition/Michael reaction sequences.
Scheme 7: Cu-catalyzed tandem conjugate addition/Michael reaction: side-product formation with chalcone (A) a...
Scheme 8: Zn enolate trapping using allyl iodides (A), Stork–Jung vinylsilane reagents (B), and allyl bromide...
Scheme 9: Cu-catalyzed tandem conjugate addition/acylation through Li R2Zn enolate (A). A four-component coup...
Scheme 10: Selected examples for the Cu-catalyzed tandem conjugate addition/trifluoromethylthiolation sequence....
Scheme 11: Zn enolates trapped by vinyloxiranes: synthesis of allylic alcohols.
Scheme 12: Stereoselective cyclopropanation of Mg enolates formed by ACA of Grignard reagents to chlorocrotona...
Scheme 13: Domino aldol reactions of Mg enolates formed from coumarin and chromone.
Scheme 14: Oxidative coupling of ACA-produced Mg enolates.
Scheme 15: Tandem ACA of Grignard reagents to enones and Mannich reaction.
Scheme 16: Diastereodivergent Mannich reaction of Mg enolates with differently N-protected imines.
Scheme 17: Tandem Grignard–ACA–Mannich using Taddol-based phosphine-phosphite ligands.
Scheme 18: Tandem reaction of Mg enolates with aminomethylating reagents.
Scheme 19: Tandem reaction composed of Grignard ACA to alkynyl enones.
Scheme 20: Rh/Cu-catalyzed tandem reaction of diazo enoates leading to cyclobutanes.
Scheme 21: Tandem Grignard-ACA of cyclopentenones and alkylation of enolates.
Scheme 22: Tandem ACA of Grignard reagents followed by enolate trapping reaction with onium compounds.
Scheme 23: Mg enolates generated from unsaturated lactones in reaction with activated alkenes.
Scheme 24: Lewis acid mediated ACA to amides and SN2 cyclization of a Br-appended enolate.
Scheme 25: Trapping reactions of aza-enolates with Michael acceptors.
Scheme 26: Si enolates generated by TMSOTf-mediated ACA of Grignard reagents and enolate trapping reaction wit...
Scheme 27: Trapping reactions of enolates generated from alkenyl heterocycles (A) and carboxylic acids (B) wit...
Scheme 28: Reactions of heterocyclic Mg enolates with onium compounds.
Scheme 29: Synthetic transformations of cycloheptatrienyl and benzodithiolyl substituents.
Scheme 30: Aminomethylation of Al enolates generated by ACA of trialkylaluminum reagents.
Scheme 31: Trapping reactions of enolates with activated alkenes.
Scheme 32: Alkynylation of racemic aluminum or magnesium enolates.
Scheme 33: Trapping reactions of Zr enolates generated by Cu-ACA of organozirconium reagents.
Scheme 34: Chloromethylation of Zr enolates using the Vilsmeier–Haack reagent.
Scheme 35: Tandem conjugate borylation with subsequent protonation or enolate trapping by an electrophile.
Scheme 36: Tandem conjugate borylation/aldol reaction of cyclohexenones.
Scheme 37: Selected examples for the tandem asymmetric borylation/intramolecular aldol reaction; synthesis of ...
Scheme 38: Cu-catalyzed tandem methylborylation of α,β-unsaturated phosphine oxide in the presence of (R,Sp)-J...
Scheme 39: Cu-catalyzed tandem transannular conjugated borylation/aldol cyclization of macrocycles containing ...
Scheme 40: Stereoselective tandem conjugate borylation/Mannich cyclization: selected examples (A) and a multi-...
Scheme 41: Some examples of Cu-catalyzed asymmetric tandem borylation/aldol cyclization (A). Application to di...
Scheme 42: Atropisomeric P,N-ligands used in tandem conjugate borylation/aldol cyclization sequence.
Scheme 43: Selected examples for the enantioselective Cu-catalyzed borylation/intramolecular Michael addition ...
Scheme 44: Selected examples for the preparation of enantioenriched spiroindanes using a Cu-catalyzed tandem c...
Scheme 45: Enantioselective conjugate borylation of cyclobutene-1-carboxylic acid diphenylmethyl ester 175 wit...
Scheme 46: Cu-catalyzed enantioselective tandem conjugate silylation of α,β-unsaturated ketones with subsequen...
Scheme 47: Cu-catalyzed enantioselective tandem conjugate silylation of α,β-unsaturated ketones with subsequen...
Scheme 48: Cu-catalyzed tandem conjugate silylation/aldol condensation. The diastereoselectivity is controlled...
Scheme 49: Chiral Ru-catalyzed three-component coupling reaction.
Scheme 50: Rh-Phebox complex-catalyzed reductive cyclization and subsequent reaction with Michael acceptors th...
Scheme 51: Rh-catalyzed tandem asymmetric conjugate alkynylation/aldol reaction (A) and subsequent spiro-cycli...
Scheme 52: Rh-bod complex-catalyzed tandem asymmetric conjugate arylation/intramolecular aldol addition (A). S...
Scheme 53: Co-catalyzed C–H-bond activation/asymmetric conjugate addition/aldol reaction.
Scheme 54: (Diisopinocampheyl)borane-promoted 1,4-hydroboration of α,β-unsaturated morpholine carboxamides and...
Figure 2: Some examples of total syntheses that have been recently reviewed.
Scheme 55: Stereoselective synthesis of antimalarial prodrug (+)-artemisinin utilizing a tandem conjugate addi...
Scheme 56: Amphilectane and serrulatane diterpenoids: preparation of chiral starting material via asymmetric t...
Scheme 57: Various asymmetric syntheses of pleuromutilin and related compounds based on a tandem conjugate add...
Scheme 58: Total synthesis of glaucocalyxin A utilizing a tandem conjugate addition/acylation reaction sequenc...
Scheme 59: Installation of the exocyclic double bond using a tandem conjugate addition/aminomethylation sequen...
Scheme 60: Synthesis of the taxol core using a tandem conjugate addition/enolate trapping sequence with Vilsme...
Scheme 61: Synthesis of the tricyclic core of 12-epi-JBIR-23/24 utilizing a Rh-catalyzed asymmetric conjugate ...
Scheme 62: Total synthesis of (−)-peyssonoside A utilizing a Cu-catalyzed enantioselective tandem conjugate ad...
Friedel–Crafts acylation of benzene derivatives in tunable aryl alkyl ionic liquids (TAAILs)
- Swantje Lerch,
- Stefan Fritsch and
- Thomas Strassner
Beilstein J. Org. Chem. 2023, 19, 212–216, doi:10.3762/bjoc.19.20
- %, with minor formation of the ortho-isomer when using benzoic acid anhydride. Bromobenzene, which is electron poor and less reactive towards acylation, was also used as a substrate in the acylation reaction, but no product was observed. This indicates that the ionic liquid 6, having the same substituent
- , 2.1 equiv formaldehyde, 2 equiv NH4Cl, MeOH, 65 °C, ii) 1.1 equiv C6H13Br, THF, 70 °C, iii) 1.1 equiv LiNTf2, DCM/MeOH/H2O, rt. Model reaction for the Friedel–Crafts acylation. Scope of the Friedel–Crafts acylation. Reaction conditions: 1 mmol benzene derivative, 2 equiv anhydride, 10 mol % FeCl3·6H2O
Graphical Abstract
Scheme 1: Synthesis of TAAILs. i) 1 equiv glyoxal, 2.1 equiv formaldehyde, 2 equiv NH4Cl, MeOH, 65 °C, ii) 1....
Scheme 2: Model reaction for the Friedel–Crafts acylation.
Figure 1: Time-dependent analysis of the reaction using varying amounts of anhydride. Reaction conditions: 1 ...
Scheme 3: Scope of the Friedel–Crafts acylation. Reaction conditions: 1 mmol benzene derivative, 2 equiv anhy...
Ionic multiresonant thermally activated delayed fluorescence emitters for light emitting electrochemical cells
- Merve Karaman,
- Abhishek Kumar Gupta,
- Subeesh Madayanad Suresh,
- Tomas Matulaitis,
- Lorenzo Mardegan,
- Daniel Tordera,
- Henk J. Bolink,
- Sen Wu,
- Stuart Warriner,
- Ifor D. Samuel and
- Eli Zysman-Colman
Beilstein J. Org. Chem. 2022, 18, 1311–1321, doi:10.3762/bjoc.18.136
- 23% overall yield. First, hydrolysis of 1, in situ conversion to the acyl chloride and subsequent Lewis acid-promoted Friedel–Crafts acylation reaction produced compound 2 (Scheme 1), where the AlCl3 was also responsible for the demethylation. Compound 2 was then subjected to monoalkylation with 1,4
Graphical Abstract
Figure 1: Chemical structures of (a) reported ionic TADF emitters for LEECs, (b) the MR-TADF emitter DiKTa an...
Scheme 1: Synthesis of DiKTa-OBuIm and DiKTa-DPA-OBuIm.
Figure 2: (a) HOMO and LUMO electron density distribution and orbital energies of DiKTa-OMe and DiKTa-DPA-OMe...
Figure 3: (a) Cyclic and differential pulse voltammograms measured in degassed MeCN with 0.1 M [n-Bu4N]PF6 as...
Figure 4: (a) Steady-state emission spectra of DiKTa-OBuIm and DiKTa-DPA-OBuIm in 1 wt % doped mCP films, λex...
Figure 5: (a) Electroluminescence spectra of DiKTa-OBuIm (green curve), DiKTa-DPA-OBuIm (red curve) and 1% of ...
Ferrocenoyl-adenines: substituent effects on regioselective acylation
- Mateja Toma,
- Gabrijel Zubčić,
- Jasmina Lapić,
- Senka Djaković,
- Davor Šakić and
- Valerije Vrček
Beilstein J. Org. Chem. 2022, 18, 1270–1277, doi:10.3762/bjoc.18.133
- kinetic and thermodynamic control of the acylation reaction. Results and Discussion It was shown that the reaction between the pyrimidine anion (uracil, thymine, or 5-fluorouracil) and FcCOCl in N,N-dimethylformamide (DMF) proceeded in a full regiospecific mode [19]. In the purine series, however, the
- descriptors for chemical reactivity, which revealed that the N7 atom is more nucleophilic than the N9 atom in all adenine derivatives. Both, steric and electronic properties are to be included when considering the regioselectivity of the acylation reaction of purines. In some cases, the regioselectivity was
Graphical Abstract
Scheme 1: Regioselective ferrocenoylation of the adenine anion 1 and its derivatives 2–6 substituted at the N6...
Figure 1: 1H NMR spectrum (downfield region) of the reaction mixture (adenine anion 1 and FcCOCl) in DMF, tak...
Figure 2: HOMO map of space distribution (left) of adenine anion (1) at the B3LYP/6-31+G(d) level of theory (...
Figure 3: Dependence of N9-isomer product ratio (%), in the reaction between FcCOCl and adenine anions 1–6, o...
Figure 4: B3LYP/6-31+G(d)/SDD optimized transition state structures for N7- (6-TSN7) and N9-ferrocenoylation (...
Figure 5: Relation between the Gibbs free energy barrier (ΔG‡) for the N7-ferrocenoylation of C6-substituted ...
Chemoselective N-acylation of indoles using thioesters as acyl source
- Tianri Du,
- Xiangmu Wei,
- Honghong Xu,
- Xin Zhang,
- Ruiru Fang,
- Zheng Yuan,
- Zhi Liang and
- Yahui Li
Beilstein J. Org. Chem. 2022, 18, 89–94, doi:10.3762/bjoc.18.9
- , Scheme 3). The results indicate that this N-acylation reaction of indole has great potential in practical synthesis. Some control experiments were conducted to explore the reaction mechanism of this transformation (Scheme 4). When S-methyl decanethioate (2i) was adopted without Cs2CO3, no decomposition
Graphical Abstract
Figure 1: Representative pharmaceuticals containing N-acylindole moieties.
Scheme 1: A) Strategies for the synthesis of N-acylindoles; B) thioester as dicarbonylation reagent; C) recen...
Scheme 2: Reactions of thioesters and indoles. Reaction conditions: 1 (0.2 mmol, 1.0 equiv), 2 (0.6 mmol, 3.0...
Scheme 3: Gram-scale experiment.
Scheme 4: Control experiments.
Scheme 5: Proposed mechanism.
Synthetic strategies toward 1,3-oxathiolane nucleoside analogues
- Umesh P. Aher,
- Dhananjai Srivastava,
- Girij P. Singh and
- Jayashree B. S
Beilstein J. Org. Chem. 2021, 17, 2680–2715, doi:10.3762/bjoc.17.182
- methoxide. Further, selective recrystallization in an appropriate solvent (toluene/hexanes) resulted in a single isomer (50:1 dr) in solution. The oxathiolane derivative 52 has the opposite configuration of that required for 3TC (1) synthesis. This acylation reaction was accomplished using pivaloyl chloride
Graphical Abstract
Figure 1: Representative modified 1,3-oxathiolane nucleoside analogues.
Figure 2: Mechanism of antiviral action of 1,3-oxathiolane nucleosides, 3TC (1) and FTC (2), as chain termina...
Figure 3: Synthetic strategies for the construction of the 1,3-oxathiolane sugar ring.
Scheme 1: Synthesis of 4 from benzoyloxyacetaldehyde (3a) and 2-mercapto-substituted dimethyl acetal 3na.
Scheme 2: Synthesis of 8 from protected glycolic aldehyde 3b and 2-mercaptoacetic acid (3o).
Scheme 3: Synthesis of 20 from ᴅ-mannose (3c).
Scheme 4: Synthesis of 20 from 1,6-thioanhydro-ᴅ-galactose (3d).
Scheme 5: Synthesis of 8 from 2-(tert-butyldiphenylsilyloxy)methyl-5-oxo-1,2-oxathiolane (3m).
Scheme 6: Synthesis of 20a from ʟ-gulose derivative 3f.
Scheme 7: Synthesis of 31 from (+)-thiolactic acid 3p and 2-benzoyloxyacetaldehyde (3a).
Scheme 8: Synthesis of 35a from 1,4-dithiane-2,5-diol (3q) and glyoxylic acid (3g) hydrate.
Scheme 9: Synthetic routes toward 41 through Pummerer reaction from methyl 2-mercaptoacetate (3j) and bromoac...
Scheme 10: Strategy for the synthesis of 2,5-substituted 1,3-oxathiolane 41a using 4-nitrobenzyl glyoxylate an...
Scheme 11: Synthesis of 44 by a resolution method using Mucor miehei lipase.
Scheme 12: Synthesis of 45 from benzoyloxyacetaldehyde (3a) and 2-mercaptoacetaldehyde bis(2-methoxyethyl) ace...
Scheme 13: Synthesis of 46 from 2-mercaptoacetaldehyde bis(2-methoxyethyl) acetal (3nc) and diethyl 3-phosphon...
Scheme 14: Synthesis of 48 from 1,3-dihydroxyacetone dimer 3l.
Scheme 15: Approach toward 52 from protected alkene 3rb and lactic acid derivative 51 developed by Snead et al....
Scheme 16: Recent approach toward 56a developed by Kashinath et al.
Scheme 17: Synthesis of 56a from ʟ-menthyl glyoxylate (3h) hydrate by DKR.
Scheme 18: Possible mechanism with catalytic TEA for rapid interconversion of isomers.
Scheme 19: Synthesis of 35a by a classical resolution method through norephedrine salt 58 formation.
Scheme 20: Synthesis of 63 via [1,2]-Brook rearrangement from silyl glyoxylate 61 and thiol 3nb.
Scheme 21: Combined use of STS and CAL-B as catalysts to synthesize an enantiopure oxathiolane precursor 65.
Scheme 22: Synthesis of 1 and 1a from glycolaldehyde dimer 64 and 1,4-dithiane-2,5-diol (3q) using STS and CAL...
Scheme 23: Synthesis of 68 by using Klebsiella oxytoca.
Scheme 24: Synthesis of 71 and 72 using Trichosporon taibachii lipase and kinetic resolution.
Scheme 25: Synthesis of 1,3-oxathiolan-5-ones 77 and 78 via dynamic covalent kinetic resolution.
Figure 4: Pathway for glycosidic bond formation.
Scheme 26: First synthesis of (±)-BCH-189 (1c) by Belleau et al.
Scheme 27: Enantioselective synthesis of 3TC (1).
Scheme 28: Synthesis of cis-diastereomer 3TC (1) from oxathiolane propionate 44.
Scheme 29: Synthesis of (±)-BCH-189 (1c) via SnCl4-mediated N-glycosylation of 8.
Scheme 30: Synthesis of (+)-BCH-189 (1a) via TMSOTf-mediated N-glycosylation of 20.
Scheme 31: Synthesis of 3TC (1) from oxathiolane precursor 20a.
Scheme 32: Synthesis of 83 via N-glycosylation of 20 with pyrimidine bases.
Scheme 33: Synthesis of 85 via N-glycosylation of 20 with purine bases.
Scheme 34: Synthesis of 86 and 87 via N-glycosylation using TMSOTf and pyrimidines.
Scheme 35: Synthesis of 90 and 91 via N-glycosylation using TMSOTf and purines.
Scheme 36: Synthesis of 3TC (1) via TMSI-mediated N-glycosylation.
Scheme 37: Stereoselective N-glycosylation for the synthesis of 1 by anchimeric assistance of a chiral auxilia...
Scheme 38: Whitehead and co-workers’ approach for the synthesis of 1 via direct N-glycosylation without an act...
Scheme 39: ZrCl4-mediated stereoselective N-glycosylation.
Scheme 40: Plausible reaction mechanism for stereoselective N-glycosylation using ZrCl4.
Scheme 41: Synthesis of enantiomerically pure oxathiolane nucleosides 1 and 2.
Scheme 42: Synthesis of tetrazole analogues of 1,3-oxathiolane nucleosides 97.
Scheme 43: Synthetic approach toward 99 from 1,3-oxathiolane 45 by Camplo et al.
Scheme 44: Synthesis of 100 from oxathiolane phosphonate analogue 46.
Scheme 45: Synthetic approach toward 102 and the corresponding cyclic thianucleoside monophosphate 102a by Cha...
Scheme 46: Synthesis of emtricitabine (2) from 1,4-dithiane-2,5-diol (3q) and glyoxylic acid (3g).
Scheme 47: Synthesis of 1 and 2, respectively, from 56a–d using iodine-mediated N-glycosylation.
Scheme 48: Plausible mechanism for silane- and I2-mediated N-glycosylation.
Scheme 49: Pyridinium triflate-mediated N-glycosylation of 35a.
Scheme 50: Possible pathway for stereoselective N-glycosylation via in situ chelation with a metal ligand.
Scheme 51: Synthesis of novel 1,3-oxathiolane nucleoside 108 from oxathiolane precursor 8 and 3-benzyloxy-2-me...
Scheme 52: Synthesis of 110 using T-705 as a nucleobase and 1,3-oxathiolane derivative 8 via N-glycosylation.
Scheme 53: Synthesis of 1 using an asymmetric leaving group and N-glycosylation with bromine and mesitylene.
Scheme 54: Cytidine deaminase for enzymatic separation of 1c.
Scheme 55: Enzymatic resolution of the monophosphate derivative 116 for the synthesis of (−)-BCH-189 (1) and (...
Scheme 56: Enantioselective resolution by PLE-mediated hydrolysis to obtain FTC (2).
Scheme 57: (+)-Menthyl chloroformate as a resolving agent to separate a racemic mixture 120.
Scheme 58: Separation of racemic mixture 1c by cocrystal 123 formation with (S)-(−)-BINOL.
Photoredox catalysis in nickel-catalyzed C–H functionalization
- Lusina Mantry,
- Rajaram Maayuri,
- Vikash Kumar and
- Parthasarathy Gandeepan
Beilstein J. Org. Chem. 2021, 17, 2209–2259, doi:10.3762/bjoc.17.143
- (Scheme 37) [120]. Here, the combination of the iridium photocatalyst, [Ir(ppy)2(dtbbpy)]PF6 and Ni(cod)2 as the nickel catalyst were found to be optimal to give the desired acylation products 74 in satisfactory yields. Furthermore, a plausible catalytic cycle was proposed to account for the C–H acylation
- reaction (Figure 16) [120]. A photogenerated α-amino radical 16-IV intercepts with the nickel catalytic cycle to generate a key nickel(III) intermediate 16-VII, which readily undergoes reductive elimination to afford the desired cross-coupled product 74a. In 2017, Kamagai and Shibasaki showed that a robust
Graphical Abstract
Scheme 1: Nickel-catalyzed cross-coupling versus C‒H activation.
Figure 1: Oxidative and reductive quenching cycles of a photocatalyst. [PC] = photocatalyst, A = acceptor, D ...
Scheme 2: Photoredox nickel-catalyzed C(sp3)–H arylation of dimethylaniline (1a).
Scheme 3: Photoredox nickel-catalyzed arylation of α-amino, α-oxy and benzylic C(sp3)‒H bonds with aryl bromi...
Figure 2: Proposed catalytic cycle for the photoredox-mediated HAT and nickel catalysis enabled C(sp3)‒H aryl...
Scheme 4: Photoredox arylation of α-amino C(sp3)‒H bonds with aryl iodides.
Figure 3: Proposed mechanism for photoredox nickel-catalyzed α-amino C‒H arylation with aryl iodides.
Scheme 5: Nickel-catalyzed α-oxy C(sp3)−H arylation of cyclic and acyclic ethers.
Figure 4: Proposed catalytic cycle for the C(sp3)−H arylation of cyclic and acyclic ethers.
Scheme 6: Photochemical nickel-catalyzed C–H arylation of ethers.
Figure 5: Proposed catalytic cycle for the nickel-catalyzed arylation of ethers with aryl bromides.
Scheme 7: Nickel-catalyzed α-amino C(sp3)‒H arylation with aryl tosylates.
Scheme 8: Arylation of α-amino C(sp3)‒H bonds by in situ generated aryl tosylates from phenols.
Scheme 9: Formylation of aryl chlorides through redox-neutral 2-functionalization of 1,3-dioxolane (13).
Scheme 10: Photochemical C(sp3)–H arylation via a dual polyoxometalate HAT and nickel catalytic manifold.
Figure 6: Proposed mechanism for C(sp3)–H arylation through dual polyoxometalate HAT and nickel catalytic man...
Scheme 11: Photochemical nickel-catalyzed α-hydroxy C‒H arylation.
Scheme 12: Photochemical synthesis of fluoxetine (21).
Scheme 13: Photochemical nickel-catalyzed allylic C(sp3)‒H arylation with aryl bromides.
Figure 7: Proposed mechanism for the photochemical nickel-catalyzed allylic C(sp3)‒H arylation with aryl brom...
Scheme 14: Photochemical C(sp3)‒H arylation by the synergy of ketone HAT catalysis and nickel catalysis.
Figure 8: Proposed mechanism for photochemical C(sp3)‒H arylation by the synergy of ketone HAT catalysis and ...
Scheme 15: Benzophenone- and nickel-catalyzed photoredox benzylic C–H arylation.
Scheme 16: Benzaldehyde- and nickel-catalyzed photoredox C(sp3)–H arylation.
Scheme 17: Photoredox and nickel-catalyzed enantioselective benzylic C–H arylation.
Figure 9: Proposed mechanism for the photoredox and nickel-catalyzed enantioselective benzylic C–H arylation.
Scheme 18: Photoredox nickel-catalyzed α-(sp3)‒H arylation of secondary benzamides with aryl bromides.
Scheme 19: Enantioselective sp3 α-arylation of benzamides.
Scheme 20: Nickel-catalyzed decarboxylative vinylation/C‒H arylation of cyclic oxalates.
Figure 10: Proposed mechanism for the nickel-catalyzed decarboxylative vinylation/C‒H arylation of cyclic oxal...
Scheme 21: C(sp3)−H arylation of bioactive molecules using mpg-CN photocatalysis and nickel catalysis.
Figure 11: Proposed mechanism for the mpg-CN/nickel photocatalytic C(sp3)–H arylation.
Scheme 22: Nickel-catalyzed synthesis of 1,1-diarylalkanes from alkyl bromides and aryl bromides.
Figure 12: Proposed mechanism for photoredox nickel-catalyzed C(sp3)–H alkylation via polarity-matched HAT.
Scheme 23: Photoredox nickel-catalyzed C(sp3)‒H alkylation via polarity-matched HAT.
Scheme 24: Benzaldehyde- and nickel-catalyzed photoredox C(sp3)‒H alkylation of ethers.
Scheme 25: Benzaldehyde- and nickel-catalyzed photoredox C(sp3)‒H alkylation of amides and thioethers.
Scheme 26: Photoredox and nickel-catalyzed C(sp3)‒H alkylation of benzamides with alkyl bromides.
Scheme 27: CzIPN and nickel-catalyzed C(sp3)‒H alkylation of ethers with alkyl bromides.
Figure 13: Proposed mechanism for the CzIPN and nickel-catalyzed C(sp3)‒H alkylation of ethers.
Scheme 28: Nickel/photoredox-catalyzed methylation of (hetero)aryl chlorides and acid chlorides using trimethy...
Figure 14: Proposed catalytic cycle for the nickel/photoredox-catalyzed methylation of (hetero)aryl chlorides ...
Scheme 29: Photochemical nickel-catalyzed C(sp3)–H methylations.
Scheme 30: Photoredox nickel catalysis-enabled alkylation of unactivated C(sp3)–H bonds with alkyl bromides.
Scheme 31: Photochemical C(sp3)–H alkenylation with alkenyl tosylates.
Scheme 32: Photoredox nickel-catalyzed hydroalkylation of internal alkynes.
Figure 15: Proposed mechanism for the photoredox nickel-catalyzed hydroalkylation of internal alkynes.
Scheme 33: Photoredox nickel-catalyzed hydroalkylation of activated alkynes with C(sp3)−H bonds.
Scheme 34: Allylation of unactivated C(sp3)−H bonds with allylic chlorides.
Scheme 35: Photochemical nickel-catalyzed α-amino C(sp3)–H allylation of secondary amides with trifluoromethyl...
Scheme 36: Photoredox δ C(sp3)‒H allylation of secondary amides with trifluoromethylated alkenes.
Scheme 37: Photoredox nickel-catalyzed acylation of α-amino C(sp3)‒H bonds of N-arylamines.
Figure 16: Proposed mechanism for the photoredox nickel-catalyzed acylation of α-amino C(sp3)–H bonds of N-ary...
Scheme 38: Photocatalytic α‑acylation of ethers with acid chlorides.
Figure 17: Proposed mechanism for the photocatalytic α‑acylation of ethers with acid chlorides.
Scheme 39: Photoredox and nickel-catalyzed C(sp3)‒H esterification with chloroformates.
Scheme 40: Photoredox nickel-catalyzed dehydrogenative coupling of benzylic and aldehydic C–H bonds.
Figure 18: Proposed reaction pathway for the photoredox nickel-catalyzed dehydrogenative coupling of benzylic ...
Scheme 41: Photoredox nickel-catalyzed enantioselective acylation of α-amino C(sp3)–H bonds with carboxylic ac...
Scheme 42: Nickel-catalyzed C(sp3)‒H acylation with N-acylsuccinimides.
Figure 19: Proposed mechanism for the nickel-catalyzed C(sp3)–H acylation with N-acylsuccinimides.
Scheme 43: Nickel-catalyzed benzylic C–H functionalization with acid chlorides 45.
Scheme 44: Photoredox nickel-catalyzed benzylic C–H acylation with N-acylsuccinimides 84.
Scheme 45: Photoredox nickel-catalyzed acylation of indoles 86 with α-oxoacids 87.
Scheme 46: Nickel-catalyzed aldehyde C–H functionalization.
Figure 20: Proposed catalytic cycle for the photoredox nickel-catalyzed aldehyde C–H functionalization.
Scheme 47: Photoredox carboxylation of methylbenzenes with CO2.
Figure 21: Proposed mechanism for the photoredox carboxylation of methylbenzenes with CO2.
Scheme 48: Decatungstate photo-HAT and nickel catalysis enabled alkene difunctionalization.
Figure 22: Proposed catalytic cycle for the decatungstate photo-HAT and nickel catalysis enabled alkene difunc...
Scheme 49: Diaryl ketone HAT catalysis and nickel catalysis enabled dicarbofunctionalization of alkenes.
Figure 23: Proposed catalytic mechanism for the diaryl ketone HAT catalysis and nickel catalysis enabled dicar...
Scheme 50: Overview of photoredox nickel-catalyzed C–H functionalizations.
Synthetic reactions driven by electron-donor–acceptor (EDA) complexes
- Zhonglie Yang,
- Yutong Liu,
- Kun Cao,
- Xiaobin Zhang,
- Hezhong Jiang and
- Jiahong Li
Beilstein J. Org. Chem. 2021, 17, 771–799, doi:10.3762/bjoc.17.67
- , which can be considered an effective method for the generation of alkyl radicals without catalyst. In 2019, Yu and Zhang [15] reported a radical acylation reaction initiated by an EDA complex promoted by visible light. Imine 122 was employed as electron acceptor with α-keto acid 109 as electron donor to
Graphical Abstract
Scheme 1: The electron transfer process in EDA complexes.
Scheme 2: Synthesis of benzo[b]phosphorus oxide 3 initiated by an EDA complex.
Scheme 3: Mechanism of the synthesis of quinoxaline derivative 7.
Scheme 4: Synthesis of imidazole derivative 10 initiated by an EDA complex.
Scheme 5: Synthesis of sulfamoylation product 12 initiated by an EDA complex.
Scheme 6: Mechanism of the synthesis of sulfamoylation product 12.
Scheme 7: Synthesis of indole derivative 22 initiated by an EDA complex.
Scheme 8: Synthesis of perfluoroalkylated pyrimidines 26 initiated by an EDA complex.
Scheme 9: Synthesis of phenanthridine derivative 29 initiated by an EDA complex.
Scheme 10: Synthesis of cis-tetrahydroquinoline derivative 32 initiated by an EDA complex.
Scheme 11: Mechanism of the synthesis of cis-tetrahydroquinoline derivative 32.
Scheme 12: Synthesis of phenanthridine derivative 38 initiated by an EDA complex.
Scheme 13: Synthesis of spiropyrroline derivative 40 initiated by an EDA complex.
Scheme 14: Synthesis of benzothiazole derivative 43 initiated by an EDA complex.
Scheme 15: Synthesis of perfluoroalkyl-s-triazine derivative 45 initiated by an EDA complex.
Scheme 16: Synthesis of indoline derivative 47 initiated by an EDA complex.
Scheme 17: Mechanism of the synthesis of spirocyclic indoline derivative 47.
Scheme 18: Synthesis of cyclobutane product 50 initiated by an EDA complex.
Scheme 19: Mechanism of the synthesis of spirocyclic indoline derivative 50.
Scheme 20: Synthesis of 1,3-oxazolidine compound 59 initiated by an EDA complex.
Scheme 21: Synthesis of trifluoromethylated product 61 initiated by an EDA complex.
Scheme 22: Synthesis of indole alkylation product 64 initiated by an EDA complex.
Scheme 23: Synthesis of perfluoroalkylation product 67 initiated by an EDA complex.
Scheme 24: Synthesis of hydrotrifluoromethylated product 70 initiated by an EDA complex.
Scheme 25: Synthesis of β-trifluoromethylated alkyne product 71 initiated by an EDA complex.
Scheme 26: Mechanism of the synthesis of 2-phenylthiophene derivative 74.
Scheme 27: Synthesis of allylated product 80 initiated by an EDA complex.
Scheme 28: Synthesis of trifluoromethyl-substituted alkynyl product 84 initiated by an EDA complex.
Scheme 29: Synthesis of dearomatized fluoroalkylation product 86 initiated by an EDA complex.
Scheme 30: Mechanism of the synthesis of dearomatized fluoroalkylation product 86.
Scheme 31: Synthesis of C(sp3)–H allylation product 91 initiated by an EDA complex.
Scheme 32: Synthesis of perfluoroalkylation product 93 initiated by an EDA complex.
Scheme 33: Synthesis of spirocyclic indolene derivative 95 initiated by an EDA complex.
Scheme 34: Synthesis of perfluoroalkylation product 97 initiated by an EDA complex.
Scheme 35: Synthesis of alkylated indole derivative 100 initiated by an EDA complex.
Scheme 36: Mechanism of the synthesis of alkylated indole derivative 100.
Scheme 37: Synthesis of arylated oxidized indole derivative 108 initiated by an EDA complex.
Scheme 38: Synthesis of 4-ketoaldehyde derivative 111 initiated by an EDA complex.
Scheme 39: Mechanism of the synthesis of 4-ketoaldehyde derivative 111.
Scheme 40: Synthesis of perfluoroalkylated olefin 118 initiated by an EDA complex.
Scheme 41: Synthesis of alkylation product 121 initiated by an EDA complex.
Scheme 42: Synthesis of acylation product 123 initiated by an EDA complex.
Scheme 43: Mechanism of the synthesis of acylation product 123.
Scheme 44: Synthesis of trifluoromethylation product 126 initiated by an EDA complex.
Scheme 45: Synthesis of unnatural α-amino acid 129 initiated by an EDA complex.
Scheme 46: Synthesis of thioether derivative 132 initiated by an EDA complex.
Scheme 47: Synthesis of S-aryl dithiocarbamate product 135 initiated by an EDA complex.
Scheme 48: Mechanism of the synthesis of S-aryl dithiocarbamate product 135.
Scheme 49: Synthesis of thioether product 141 initiated by an EDA complex.
Scheme 50: Mechanism of the synthesis of borate product 144.
Scheme 51: Synthesis of boronation product 148 initiated by an EDA complex.
Scheme 52: Synthesis of boration product 151 initiated by an EDA complex.
Scheme 53: Synthesis of boronic acid ester derivative 154 initiated by an EDA complex.
Scheme 54: Synthesis of β-azide product 157 initiated by an EDA complex.
Scheme 55: Decarboxylation reaction initiated by an EDA complex.
Scheme 56: Synthesis of amidated product 162 initiated by an EDA complex.
Scheme 57: Synthesis of diethyl phenylphosphonate 165 initiated by an EDA complex.
Scheme 58: Mechanism of the synthesis of diethyl phenylphosphonate derivative 165.
Scheme 59: Synthesis of (Z)-2-iodovinyl phenyl ether 168 initiated by an EDA complex.
Scheme 60: Mechanism of the synthesis of (Z)-2-iodovinyl phenyl ether derivative 168.
Scheme 61: Dehalogenation reaction initiated by an EDA complex.
When metal-catalyzed C–H functionalization meets visible-light photocatalysis
- Lucas Guillemard and
- Joanna Wencel-Delord
Beilstein J. Org. Chem. 2020, 16, 1754–1804, doi:10.3762/bjoc.16.147
- the transformation, which was a Ru-based photosensitizer in that case [95]. This time, the acylation reaction was exclusively performed in batch and the protocol was compatible with various substrates bearing synthetically useful functional groups. Numerous coupling products were hence obtained in
Graphical Abstract
Figure 1: Concept of dual synergistic catalysis.
Figure 2: Classification of catalytic systems involving two catalysts.
Figure 3: General mechanism for the dual nickel/photoredox catalytic system.
Figure 4: General mechanisms for C–H activation catalysis involving different reoxidation strategies.
Figure 5: Indole synthesis via dual C–H activation/photoredox catalysis.
Figure 6: Proposed mechanism for the indole synthesis via dual catalysis.
Figure 7: Oxidative Heck reaction on arenes via the dual catalysis.
Figure 8: Proposed mechanism for the Heck reaction on arenes via dual catalysis.
Figure 9: Oxidative Heck reaction on phenols via the dual catalysis.
Figure 10: Proposed mechanism for the Heck reaction on phenols via dual catalysis.
Figure 11: Carbazole synthesis via dual C–H activation/photoredox catalysis.
Figure 12: Proposed mechanism for the carbazole synthesis via dual catalysis.
Figure 13: Carbonylation of enamides via the dual C–H activation/photoredox catalysis.
Figure 14: Proposed mechanism for carbonylation of enamides via dual catalysis.
Figure 15: Annulation of benzamides via the dual C–H activation/photoredox catalysis.
Figure 16: Proposed mechanism for the annulation of benzamides via dual catalysis.
Figure 17: Synthesis of indoles via the dual C–H activation/photoredox catalysis.
Figure 18: Proposed mechanism for the indole synthesis via dual catalysis.
Figure 19: General concept of dual catalysis merging C–H activation and photoredox catalysis.
Figure 20: The first example of dual catalysis merging C–H activation and photoredox catalysis.
Figure 21: Proposed mechanism for the C–H arylation with diazonium salts via dual catalysis.
Figure 22: Dual catalysis merging C–H activation/photoredox using diaryliodonium salts.
Figure 23: Direct arylation via the dual catalytic system reported by Xu.
Figure 24: Direct arylation via dual catalytic system reported by Balaraman.
Figure 25: Direct arylation via dual catalytic system reported by Guo.
Figure 26: C(sp3)–H bond arylation via the dual Pd/photoredox catalytic system.
Figure 27: Acetanilide derivatives acylation via the dual C–H activation/photoredox catalysis.
Figure 28: Proposed mechanism for the C–H acylation with α-ketoacids via dual catalysis.
Figure 29: Acylation of azobenzenes via the dual catalysis C–H activation/photoredox.
Figure 30: C2-acylation of indoles via the dual C–H activation/photoredox catalysis.
Figure 31: Proposed mechanism for the C2-acylation of indoles with aldehydes via dual catalysis.
Figure 32: C2-acylation of indoles via the dual C–H activation/photoredox catalysis.
Figure 33: Perfluoroalkylation of arenes via the dual C–H activation/photoredox catalysis.
Figure 34: Proposed mechanism for perfluoroalkylation of arenes via dual catalysis.
Figure 35: Sulfonylation of 1-naphthylamides via the dual C–H activation/photoredox catalysis.
Figure 36: Proposed mechanism for sulfonylation of 1-naphthylamides via dual catalysis.
Figure 37: meta-C–H Alkylation of arenes via visible-light metallaphotocatalysis.
Figure 38: Alternative procedure for meta-C–H alkylation of arenes via metallaphotocatalysis.
Figure 39: Proposed mechanism for meta-C–H alkylation of arenes via metallaphotocatalysis.
Figure 40: C–H borylation of arenes via visible-light metallaphotocatalysis.
Figure 41: Proposed mechanism for C–H borylation of arenes via visible-light metallaphotocatalysis.
Figure 42: Undirected C–H aryl–aryl cross coupling via dual gold/photoredox catalysis.
Figure 43: Proposed mechanism for the undirected C–H aryl–aryl cross-coupling via dual catalysis.
Figure 44: Undirected C–H arylation of (hetero)arenes via dual manganese/photoredox catalysis.
Figure 45: Proposed mechanism for the undirected arylation of (hetero)arenes via dual catalysis.
Figure 46: Photoinduced C–H arylation of azoles via copper catalysis.
Figure 47: Photo-induced C–H chalcogenation of azoles via copper catalysis.
Figure 48: Decarboxylative C–H adamantylation of azoles via dual cobalt/photoredox catalysis.
Figure 49: Proposed mechanism for the C–H adamantylation of azoles via dual catalysis.
Figure 50: General mechanisms for the “classical” (left) and Cu-free variant (right) Sonogoshira reaction.
Figure 51: First example of a dual palladium/photoredox catalysis for Sonogashira-type couplings.
Figure 52: Arylation of terminal alkynes with diazonium salts via dual gold/photoredox catalysis.
Figure 53: Proposed mechanism for the arylation of terminal alkynes via dual catalysis.
Figure 54: C–H Alkylation of alcohols promoted by H-atom transfer (HAT).
Figure 55: Proposed mechanism for the C–H alkylation of alcohols promoted by HAT.
Figure 56: C(sp3)–H arylation of latent nucleophiles promoted by H-atom transfer.
Figure 57: Proposed mechanism for the C(sp3)–H arylation of latent nucleophiles promoted by HAT.
Figure 58: Direct α-arylation of alcohols promoted by H-atom transfer.
Figure 59: Proposed mechanism for the direct α-arylation of alcohols promoted by HAT.
Figure 60: C–H arylation of amines via dual Ni/photoredox catalysis.
Figure 61: Proposed mechanism for the C–H arylation of amines via dual Ni/photoredox catalysis.
Figure 62: C–H functionalization of nucleophiles via excited ketone/nickel dual catalysis.
Figure 63: Proposed mechanism for the C–H functionalization enabled by excited ketones.
Figure 64: Selective sp3–sp3 cross-coupling promoted by H-atom transfer.
Figure 65: Proposed mechanism for the selective sp3–sp3 cross-coupling promoted by HAT.
Figure 66: Direct C(sp3)–H acylation of amines via dual Ni/photoredox catalysis.
Figure 67: Proposed mechanism for the C–H acylation of amines via dual Ni/photoredox catalysis.
Figure 68: C–H hydroalkylation of internal alkynes via dual Ni/photoredox catalysis.
Figure 69: Proposed mechanism for the C–H hydroalkylation of internal alkynes.
Figure 70: Alternative procedure for the C–H hydroalkylation of ynones, ynoates, and ynamides.
Figure 71: Allylic C(sp3)–H activation via dual Ni/photoredox catalysis.
Figure 72: Proposed mechanism for the allylic C(sp3)–H activation via dual Ni/photoredox catalysis.
Figure 73: Asymmetric allylation of aldehydes via dual Cr/photoredox catalysis.
Figure 74: Proposed mechanism for the asymmetric allylation of aldehydes via dual catalysis.
Figure 75: Aldehyde C–H functionalization promoted by H-atom transfer.
Figure 76: Proposed mechanism for the C–H functionalization of aldehydes promoted by HAT.
Figure 77: Direct C–H arylation of strong aliphatic bonds promoted by HAT.
Figure 78: Proposed mechanism for the C–H arylation of strong aliphatic bonds promoted by HAT.
Figure 79: Direct C–H trifluoromethylation of strong aliphatic bonds promoted by HAT.
Figure 80: Proposed mechanism for the C–H trifluoromethylation of strong aliphatic bonds.
One-step route to tricyclic fused 1,2,3,4-tetrahydroisoquinoline systems via the Castagnoli–Cushman protocol
- Aleksandar Pashev,
- Nikola Burdzhiev and
- Elena Stanoeva
Beilstein J. Org. Chem. 2020, 16, 1456–1464, doi:10.3762/bjoc.16.121
- proposal features a stepwise Mannich-type reaction of the enolized anhydride 17 to the imine component and a subsequent N-acylation reaction to form the lactam target product [24]. A respective Mannich-type intermediate has been recently isolated and subsequently converted into the target lactam product
Graphical Abstract
Figure 1: Compounds comprising a benzo[a]quinolizidine ring system.
Scheme 1: Reactions between enolizable anhydrides and imines.
Scheme 2: Mechanistic pathways for the reaction between cyclic anhydrides and imines.
Scheme 3: Retrosynthetic analysis of the target compounds.
Scheme 4: Reaction of 6,7-dimethoxy-3,4-dihydroisoquinoline (18) with anhydrides 5–8. Reagents and conditions...
Figure 2: Representative NOE interactions in cis and trans-21–24 (only one enantiomer is shown).
Scheme 5: Reaction of 1-methyl-3,4-dihydroisoquinoline (19) with anhydrides 5–7. Reagents and conditions: xyl...
Figure 3: X-ray crystal structure of products 25 and 26.
Scheme 6: Reactions of 1-alkyl-3,4-dihydroisoquinolines 19 and 20 with anhydride 8. Reagents and conditions: ...
Figure 4: Representative NOE interactions in 28 and 29.
Scheme 7: Suggested mechanism for the formation of products 25–27.
[1,3]/[1,4]-Sulfur atom migration in β-hydroxyalkylphosphine sulfides
- Katarzyna Włodarczyk,
- Piotr Borowski and
- Marek Stankevič
Beilstein J. Org. Chem. 2020, 16, 88–105, doi:10.3762/bjoc.16.11
- ]-rearrangement proceeded with additional partial enrichment of one enantiomer. The latter may have occurred through the preferential acylation of one of two diastereoisomers under the reaction conditions where the second chirality center at the phosphorus atom influenced the ratio of the acylation reaction. With
Graphical Abstract
Scheme 1: Arbusov, phospha-Fries, and phospha-Brook rearrangements.
Scheme 2: Cyclization of 1a and 1b under acidic conditions.
Scheme 3: The synthesis of P-stereogenic β-hydroxyalkylphosphine sulfides.
Scheme 4: Cyclization of 8 and 19 in the presence of H3PO4.
Scheme 5: Cyclization of (SP)-19 in the presence of H3PO4.
Figure 1: 1H NMR spectra of compounds 12 and 29.
Figure 2: 13C NMR spectra of compounds 12 and 29.
Scheme 6: Synthesis of the alkenylphosphine sulfides used in study.
Scheme 7: The reaction of mesylate compounds with Lewis-acidic AlCl3.
Scheme 8: The reaction of alkenylphosphine sulfides with AlCl3.
Scheme 9: Rearrangement of 20 in the presence of Brønsted acid. The calculated energies next to the arrows ar...
Scheme 10: Rearrangement of 20 in the presence of Lewis acid. The calculated energies next to the arrows are r...
Scheme 11: The synthesis of chiral substrates for rearrangement reactions.
Scheme 12: The reaction of (SP)-60 and (SP)-65 with AlCl3.
Scheme 13: Reaction of chiral β-hydroxyalkylphosphine sulfides with Brønsted acid.
Scheme 14: Attempted cyclization of enantiomerically enriched 53 and 46.
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
- ash-supported Sc(OTf)3 for Friedal–Crafts acylation reaction, also the group of Fukuzawa has exploited Sc(OTf)3 in the synthesis of N-substituted 1,4-DHPs [26][82]. Enhancement in reactivity and selectivity of many reactions, ability to polarize bonds upon coordination and thus altering their
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.
Mechanochemical Friedel–Crafts acylations
- Mateja Đud,
- Anamarija Briš,
- Iva Jušinski,
- Davor Gracin and
- Davor Margetić
Beilstein J. Org. Chem. 2019, 15, 1313–1320, doi:10.3762/bjoc.15.130
- a few examples of FCRs employing manual grinding: reserpine acylation with AlCl3 [6] and acylation reaction of aromatics [7]. One of the reasons for this scarcity is the hygroscopic nature of the aluminum trichloride catalyst [8][9][10][11][12] when exposed to air humidity. This problem could be
- , entries 18–23), which did not lead to formation of products. Experiments collected in Table 1 demonstrate that a FC acylation reaction could be effectively carried out under ball-milling conditions at room temperature without the use of solvent. This reaction could be easily scaled up from 94 to 500 mg of
Graphical Abstract
Scheme 1: FCR of pyrene and phthalic anhydride.
Scheme 2: Scope of acylation reagents in FCR under mechanochemical activation conditions and comparison with ...
Scheme 3: Scope of aromatic substrates in FCR under mechanochemical activation conditions. aIsolated yields.
Scheme 4: Mechanochemical regiodirected FCR of anthracene dimer and succinic anhydride.
Scheme 5: Regioselectivity direction by protection of 9,10-anthracene ring positions.
Scheme 6: Double FCR of phthaloyl chloride and aromatics.
Figure 1: In situ Raman monitoring of reaction of phthalic anhydride with p-xylene.
Synthesis of a leopolic acid-inspired tetramic acid with antimicrobial activity against multidrug-resistant bacteria
- Luce Mattio,
- Loana Musso,
- Leonardo Scaglioni,
- Andrea Pinto,
- Piera Anna Martino and
- Sabrina Dallavalle
Beilstein J. Org. Chem. 2018, 14, 2482–2487, doi:10.3762/bjoc.14.224
- hand, we finally accomplished the N-acylation reaction using n-BuLi in THF at −60 °C [15] in 60% yield. Removal of both protecting groups by catalytic hydrogenation, gave the desired compound 1 in 72% yield (Scheme 3). Compound 1 was subjected to a preliminary study to evaluate the antimicrobial
Graphical Abstract
Figure 1: Structures of leopolic acid A and compound 1.
Scheme 1: Synthesis of 3-decyltetramic intermediate 13. Reagent and conditions: a) TEA, THF, 0 °C to rt, 2.5 ...
Scheme 2: Synthesis of dipeptide L-Phe-L-Val intermediate 20. Reagents and conditions: a) PTSA·H2O, benzyl al...
Scheme 3: Synthesis of compound 1. Reagents and conditions: a) n-BuLi, THF, −60 °C, 220 min, 60%; b) H2, Pd/C...
α-Acetoxyarone synthesis via iodine-catalyzed and tert-butyl hydroperoxide-mediateded self-intermolecular oxidative coupling of aryl ketones
- Liquan Tan,
- Cui Chen and
- Weibing Liu
Beilstein J. Org. Chem. 2017, 13, 1079–1084, doi:10.3762/bjoc.13.107
- previous reports [22][29]. Conclusion In summary, we have developed an efficient, novel, and metal-free synthesis of α-acetoxyaryl ketones from aryl ketones using I2−TBHP. A facile α-acylation reaction involving self-intermolecular oxidative coupling of aryl ketones was observed for the first time in the
Graphical Abstract
Scheme 1: Previous and present approaches.
Scheme 2: Substrate scope. (All of these reactions were carried out on a 2.0 mmol scale using CH3CN (2.0 mL) ...
Scheme 3: Control reactions for clarifying the mechanism.
Scheme 4: Plausible mechanism.
Derivatives of the triaminoguanidinium ion, 5. Acylation of triaminoguanidines leading to symmetrical tris(acylamino)guanidines and mesoionic 1,2,4-triazolium-3-aminides
- Jan Szabo,
- Julian Greiner and
- Gerhard Maas
Beilstein J. Org. Chem. 2017, 13, 579–588, doi:10.3762/bjoc.13.57
- conditions (see Scheme 1) also does not occur. On the other hand, the analogous acylation reaction could not be performed with benzoyl chloride and acetyl chloride under various conditions, including the application of weaker bases (NEt3, Na2CO3) in dioxane and other aprotic-polar solvents. Reaction of 1,2,3
Graphical Abstract
Scheme 1: Reactions of aminoguanidines with carboxylic acids and acid chlorides. The structural formulae show...
Scheme 2: Threefold N-acylation of triaminoguanidinium chloride (1) with acyl chloride 2b.
Scheme 3: Reaction of 1,2,3-tris(benzylamino)guanidinium salts 4 and 5 with acyl chlorides to give 1,2,3-tris...
Figure 1: Molecular structure of 6b·2C2H5OH in the solid state, with numbering of atoms (ORTEP plot). Selecte...
Scheme 4: Protonation and methylation of 1,2,4-triazolium-3-aminides 7b,c.
Scheme 5: Catalytic hydrogenation/debenzylation of betaines 7.
Figure 2: Left: molecular structure of 8b in the solid state (OLEX2 plot). Right: crystal structure viewed al...
Figure 3: Left: solid-state structure of 9b·H2O (ORTEP plot). Right: centrosymmetric hydrogen-bonded dimer of...
Figure 4: Solid-state structure of mesoionic compound 7a (ORTEP plot); thermal displacement ellipsoids are dr...
Figure 5: UV–vis spectra of 7a–d in chloroform (c = 0.04 mmol L−1); λmax [nm] (ε [L mol−1 cm−1]): 7a: 350 (47...
A novel method for heterocyclic amide–thioamide transformations
- Walid Fathalla,
- Ibrahim A. I. Ali and
- Pavel Pazdera
Beilstein J. Org. Chem. 2017, 13, 174–181, doi:10.3762/bjoc.13.20
- heating isatine with malonic acid followed by esterification of the produced quinoline carboxylic acid with methanol in the presence of sulfuric acid at 80 °C for 6 h. 4-Arylphthalazin-1(2H)-ones A7 and A8 [24][25] were prepared by Friedel–Crafts acylation reaction of N-aminophthalimide with either
Graphical Abstract
Scheme 1: Synthesis of N-cyclohexyl dithiocarbamate cyclohexylammonium salt (2).
Scheme 2: The two-step thiation of quinazolin-4-one A1–6 and phthalazin-1-ones A7 and A8.
Scheme 3: Thiation of quinoline A9 and quinoxalinone A10–13.
Scheme 4: Rational mechanism of the reaction of 4-chloro-2-phenylquinazoline (B2) to 2-phenylquinazolin-4(3H)...
Solvent-free synthesis of novel para-menthane-3,8-diol ester derivatives from citronellal using a polymer-supported scandium triflate catalyst
- Lubabalo Mafu,
- Ben Zeelie and
- Paul Watts
Beilstein J. Org. Chem. 2016, 12, 2046–2054, doi:10.3762/bjoc.12.193
- of alcohols, thiols and amines is a fundamental reaction in organic synthesis. It is mostly used to protect these functional groups in multi-step synthesis processes. The acylation reaction is typically carried-out with activated carboxylic acid derivatives such as acid anhydrides [5], acyl halides
- the acylation reaction with acid anhydrides (Scheme 3). It needs to be clarified that earlier attempts to perform classic esterifications by reaction of the alcohols with a carboxylic acid were not particularly successful, as very complex reaction mixtures were produced as a result of dehydration of
- determine the effect of temperature and reaction time towards the diester formation, the acylation reaction of para-menthane-3,8-diol (3) with acetic anhydride 5 was carried out using equimolar amounts of reagent (i.e. 2 equivalents of anhydride per mole of diol). The reaction was conducted at various
Graphical Abstract
Scheme 1: Synthesis of menthol.
Scheme 2: Synthesis of para-menthane-3,8-diol.
Scheme 3: Synthesis of para-menthane diester derivatives.
Figure 1: PMD conversion using stoichiometric quantities of acetic anhydride.
Figure 2: Product distribution as a function of time.
Figure 3: Product distribution as a function of time.
Figure 4: Effect of molar ratio in product distribution.
Scheme 4: Synthesis of para-menthane mono-ester derivatives.
Chemoselective O-acylation of hydroxyamino acids and amino alcohols under acidic reaction conditions: History, scope and applications
- Tor E. Kristensen
Beilstein J. Org. Chem. 2015, 11, 446–468, doi:10.3762/bjoc.11.51
- hydrolysates [5]. Conversion of amino acids to their copper salts elegantly masks both amino acid functionalities, thus protecting them during a subsequent alkaline acylation reaction that targets the side-chain functionality selectively. The side-chain-acylated lysine can then be liberated by decomposition of
- chemoselectively O,O’-diacetylated at gram-scale with acetyl bromide in anhydrous CF3CO2H (Scheme 15). Additionally, this is also a rare example of the use of an acyl bromide in an acidic O-acylation reaction. Individual examples of acidic O-acylation reactions are scattered throughout the literature. In 1976
Graphical Abstract
Scheme 1: Selective O-acetylation of hydroxyamino acids with acetic anhydride in perchloric acid-acetic acid ...
Scheme 2: Selective O-acetylation of L-tyrosine as reported by Bretschneider and Biemann in 1950 [13].
Scheme 3: Selective O-acetylation of L-serine in acetic acid saturated with hydrogen chloride as reported by ...
Scheme 4: Chemoselective O-acetylation of hydroxyamino acids with acetyl chloride in hydrochloric acid–acetic...
Scheme 5: Chemoselective O-acylation of hydroxyamino acids with acyl chlorides in anhydrous trifluoroacetic a...
Scheme 6: Chemoselective O-acylation of hydroxyproline with acyl chlorides or carboxylic anhydrides in methan...
Scheme 7: Chemoselective O-acetylation of L-DOPA as reported by Fuller, Verlander and Goodman in 1978 [35].
Scheme 8: Chemoselective O-acylation of L-tyrosine as reported by Huang, Kimura, Bawarshi-Nassar and Hussain ...
Scheme 9: Preparation of proline amphiphiles or acrylic proline monomers (for macromolecular synthesis) by ch...
Scheme 10: Preparation of amphiphilic organocatalysts from serine, threonine and cysteine by chemoselective O-...
Scheme 11: Preparation of amphiphilic proline organocatalysts by chemoselective O-acylation with acyl chloride...
Scheme 12: Amphiphilic organocatalysts prepared from hydroxyamino acids and isosteviol by chemoselective O-acy...
Scheme 13: Preparation of acrylic proline precursors for polymeric organocatalysts by chemoselective O-acylati...
Scheme 14: Conversion of trans-4-hydroxy-L-proline to cis-4-hydroxy-D-proline·HCl and subsequent chemoselectiv...
Scheme 15: Some examples of chemoselective O-acylation of amino alcohols under acidic reaction conditions repo...
Scheme 16: An assembly of chiral acrylic building blocks useful in the synthesis of polymer-supported diphenyl...
Scheme 17: The chemoselective pentaacetylation of D-glucamine under acidic reaction conditions [95].
First chemoenzymatic stereodivergent synthesis of both enantiomers of promethazine and ethopropazine
- Paweł Borowiecki,
- Daniel Paprocki and
- Maciej Dranka
Beilstein J. Org. Chem. 2014, 10, 3038–3055, doi:10.3762/bjoc.10.322
- acetaldehyde, thus shifting the state of equilibrium in product direction. Therefore, in next experiments three different vinyl esters were used: vinyl acetate, vinyl butanoate, and vinyl decanoate. The influence of the acyl donor nature on the course of the alcohol acylation reaction was examined using 3
Graphical Abstract
Scheme 1: Chemoenzymatic synthesis of enantioenriched enantiomers of promethazine 9 and ethopropazine 10. Rea...
Figure 1: Dependence of optical purities (% ee) of (R)-(−)-6a (red curve, ■) and (S)-(+)-5 (blue curve, ▲) on...
Scheme 2: Assignment of the stereochemistry of enantiopure alcohol (+)-5 resulting from derivatization with (R...
Figure 2: Description of substituents for determination of the absolute configuration of (+)-5 and ΔδRS value...
Figure 3: 1H NMR (CDCl3, 400 MHz) spectra of the (R)-MPA 11 (red colored line) and (S)-MPA and 12 (blue color...
Figure 4: An ORTEP plot of (S)-(+)-1-(10H-phenothiazin-10-yl)propan-2-ol (S)-(+)-5. The following crystal str...
Scheme 3: Amination of optically active bromo derivatives (R)-(+)-8 or (S)-(−)-8 in toluene.
Scheme 4: Amination of optically active bromo derivatives (R)-(+)-8 or (S)-(−)-8 in methanol.
Scheme 5: The proposed reaction mechanism for amination of optically active (S)-(−)-8 in methanol.
Linear-g-hyperbranched and cyclodextrin-based amphiphilic block copolymer as a multifunctional nanocarrier
- Yamei Zhao,
- Wei Tian,
- Guang Yang and
- Xiaodong Fan
Beilstein J. Org. Chem. 2014, 10, 2696–2703, doi:10.3762/bjoc.10.284
- acylation reaction (Scheme S1). As illustrated in Supporting Information File 1, Scheme S1, the PHEMA-based macro chain transfer agent (PHEMA-macroCTA) carrying abundant hydroxy groups was prepared by using S,S’-bis(α,α’-dimethylacetic acid) trithiocarbonate (BDATTC) as a highly efficient chain transfer
Graphical Abstract
Scheme 1: Schematic representation of the details for the construction of a multifunctional nanocarrier used ...
Figure 1: Particle size distributions of MP1, MP2, and MP3 at 25 °C as determined by DLS.
Figure 2: TEM images of P1 (A), P2 (B) and P3 (C) micelles.
Figure 3: UV–vis spectra of LND solutions in the presence of MP1, MP2 and MP3 in buffer solutions.
Figure 4: Particle size distributions of DLMP1, DLMP2, and DLMP3 at 25 °C.
Figure 5: Stability investigation of DLMP1, DLMP2, and DLMP3.
Figure 6: Release profiles (a) and release kinetics (b–d) of LND from DLMP1, DLMP2 and DLMP3 in buffer soluti...
