Search for "natural compounds" in Full Text gives 93 result(s) in Beilstein Journal of Organic Chemistry.
Beilstein J. Org. Chem. 2024, 20, 2644–2654, doi:10.3762/bjoc.20.222
Graphical Abstract
Figure 1: Total ion chromatogram of an extract of the scent gland of a Mangshan pit viper. Compounds A–F are ...
Figure 2: Mass spectra of compounds A–F show characteristic similarities with m/z 141 and ions of the series m...
Figure 3: Structural proposals for compounds A–F.
Scheme 1: Synthesis of methyl 4,6-dimethyldodec-5-enoate (6). ACN: acetonitrile.
Figure 4: Mass spectrum of synthetic methyl (E)-4,6-dimethyldodec-5-enoate (E-6), identical with compound D.
Figure 5: Mass spectrum of cyclo(valyl-proline).
Beilstein J. Org. Chem. 2024, 20, 1839–1879, doi:10.3762/bjoc.20.162
Graphical Abstract
Scheme 1: Mechanism of the GBB reaction.
Scheme 2: Comparison of the performance of Sc(OTf)3 with some RE(OTf)3 in a model GBB reaction. Conditions: a...
Scheme 3: Comparison of the performance of various Brønsted acid catalysts in the synthesis of GBB adduct 6. ...
Scheme 4: Synthesis of Brønsted acidic ionic liquid catalyst 7. Conditions: a) neat, 60 °C, 24 h; b) TfOH, DC...
Scheme 5: Aryliodonium derivatives as organic catalysts in the GBB reaction. In the box the proposed binding ...
Scheme 6: DNA-encoded GBB reaction in micelles made of amphiphilic polymer 13. Conditions: a) 13 (50 equiv), ...
Scheme 7: GBB reaction catalyzed by cyclodextrin derivative 14. Conditions: a) 14 (1 mol %), water, 100 °C, 4...
Scheme 8: Proposed mode of activation of CALB. a) activation of the substrates; b) activation of the imine; c...
Scheme 9: One-pot GBB reaction–Suzuki coupling with a bifunctional hybrid biocatalyst. Conditions: a) Pd(0)-C...
Scheme 10: GBB reaction employing 5-HMF (23) as carbonyl component. Conditions: a) TFA (20 mol %), EtOH, 60 °C...
Scheme 11: GBB reaction with β-C-glucopyranosyl aldehyde 26. Conditions: a) InCl3 (20 mol %), MeOH, 70 °C, 2–3...
Scheme 12: GBB reaction with diacetylated 5-formyldeoxyuridine 29, followed by deacetylation of GBB adduct 30....
Scheme 13: GBB reaction with glycal aldehydes 32. Conditions: a) HFIP, 25 °C, 2–4 h.
Scheme 14: Vilsmeier–Haack formylation of 6-β-acetoxyvouacapane (34) and subsequent GBB reaction. Conditions: ...
Scheme 15: GBB reaction of 4-formlyl-PCP 37. Conditions: a) HOAc or HClO4, MeOH/DCM (2:3), rt, 3 d.
Scheme 16: GBB reaction with HexT-aldehyde 39. Conditions: a) 39 (20 nmol) and amidine (20 μmol), MeOH, rt, 6 ...
Scheme 17: GBB reaction of 2,4-diaminopirimidine 41. Conditions: a) Sc(OTf)3 (20 mol %), MeCN, 120 °C (MW), 1 ...
Scheme 18: Synthesis of N-edited guanine derivatives from 3,6-diamine-1,2,4-triazin-5-one 44. Conditions: a) S...
Scheme 19: Synthesis of 2-aminoimidazoles 49 by a Mannich-3CR followed by a one-pot intramolecular oxidative a...
Scheme 20: On DNA Suzuki–Miyaura reaction followed by GBB reaction. Conditions: a) CsOH, sSPhos-Pd-G2; b) AcOH...
Scheme 21: One-pot cascade synthesis of 5-iminoimidazoles. Conditions: a) Na2SO4, DMF, 220 °C (MW).
Scheme 22: GBB reaction of 5-amino-1H-imidazole-4-carbonile 57. Conditions: a) HClO4 (5 mol %), MeOH, rt, 24 h....
Scheme 23: One-pot cascade synthesis of indole-imidazo[1,2,a]pyridine hybrids. In blue the structural motif in...
Scheme 24: One-pot cascade synthesis of fused polycyclic indoles 67 or 69 from indole-3-carbaldehyde. Conditio...
Scheme 25: One-pot cascade synthesis of linked- and bridged polycyclic indoles from indole-2-carbaldehyde (70)...
Scheme 26: One-pot cascade synthesis of pentacyclic dihydroisoquinolines (X = N or CH). In blue the structural...
Scheme 27: One-pot stepwise synthesis of imidazopyridine-fused benzodiazepines 85. Conditions: a) p-TsOH (20 m...
Scheme 28: One-pot stepwise synthesis of benzoxazepinium-fused imidazothiazoles 89. Conditions: a) Yb(OTf)3 (2...
Scheme 29: One-pot stepwise synthesis of fused imidazo[4,5,b]pyridines 95. Conditions: a) HClO4, MeOH, rt, ove...
Scheme 30: Synthesis of heterocyclic polymers via the GBB reaction. Conditions: a) p-TsOH, EtOH, 70 °C, 24 h.
Scheme 31: One-pot multicomponent reaction towards the synthesis of covalent organic frameworks via the GBB re...
Scheme 32: One-pot multicomponent reaction towards the synthesis of covalent organic frameworks via the GBB re...
Scheme 33: GBB-like multicomponent reaction towards the synthesis of benzothiazolpyrroles (X = S) and benzoxaz...
Scheme 34: GBB-like multicomponent reaction towards the formation of imidazo[1,2,a]pyridines. Conditions: a) I2...
Scheme 35: Post-functionalization of GBB products via Ugi reaction. Conditions a) HClO4, DMF, rt, 24 h; b) MeO...
Scheme 36: Post-functionalization of GBB products via Click reaction. Conditions: a) solvent-free, 150 °C, 24 ...
Scheme 37: Post-functionalization of GBB products via cascade alkyne–allene isomerization–intramolecular nucle...
Scheme 38: Post-functionalization of GBB products via metal-catalyzed intramolecular N-arylation. In red and b...
Scheme 39: Post-functionalization of GBB products via isocyanide insertion (X = N or CH). Conditions: a) HClO4...
Scheme 40: Post-functionalization of GBB products via intramolecular nucleophilic addition to nitriles. Condit...
Scheme 41: Post-functionalization of GBB products via Pictet–Spengler cyclization. Conditions: a) 4 N HCl/diox...
Scheme 42: Post-functionalization of GBB products via O-alkylation. Conditions: a) TFA (20 mol %), EtOH, 120 °...
Scheme 43: Post-functionalization of GBB products via macrocyclization (X = -CH2CH2O-, -CH2-, -(CH2)4-). Condi...
Figure 1: Antibacterial activity of GBB-Ugi adducts 113 on both Gram-negative and Gram-positive strains.
Scheme 44: GBB multicomponent reaction using trimethoprim as the precursor. Conditions: a) Yb(OTf)3 or Y(OTf)3...
Figure 2: Antibacterial activity of GBB adducts 152 against MRSA and VRE; NA = not available.
Figure 3: Antibacterial activity of GBB adduct 153 against Leishmania amazonensis promastigotes and amastigot...
Figure 4: Antiviral and anticancer evaluation of the GBB adducts 154a and 154b. In vitro antiproliferative ac...
Figure 5: Anticancer activity of the GBB-furoxan hybrids 145b, 145c and 145d determined through antiprolifera...
Scheme 45: Synthesis and anticancer activity of the GBB-gossypol conjugates. Conditions: a) Sc(OTf)3 (10 mol %...
Figure 6: Anticancer activity of polyheterocycles 133a and 136a against human neuroblastoma. Clonogenic assay...
Figure 7: Development of GBB-adducts 158a and 158b as PD-L1 antagonists. HTRF assays were carried out against...
Figure 8: Development of imidazo[1,2-a]pyridines and imidazo[1,2-a]pyrazines as TDP1 inhibitors. The SMM meth...
Figure 9: GBB adducts 164a–c as anticancer through in vitro HDACs inhibition assays. Additional cytotoxic ass...
Figure 10: GBB adducts 165, 166a and 166b as anti-inflammatory agents through HDAC6 inhibition; NA = not avail...
Scheme 46: GBB reaction of triphenylamine 167. Conditions: a) NH4Cl (10 mol %), MeOH, 80 °C (MW), 1 h.
Scheme 47: 1) Modified GBB-3CR. Conditions: a) TMSCN (1.0 equiv), Sc(OTf)3 (0.2 equiv), MeOH, 140 °C (MW), 20 ...
Scheme 48: GBB reaction to assemble imidazo-fused heterocycle dimers 172. Conditions: a) Sc(OTf)3 (20 mol %), ...
Figure 11: Model compounds 173 and 174, used to study the acid/base-triggered reversible fluorescence response...
Beilstein J. Org. Chem. 2024, 20, 1831–1838, doi:10.3762/bjoc.20.161
Graphical Abstract
Figure 1: (A) The general structures of isoalloxazine (flavin, Fl), alloxazine (All), 5-deazaisoalloxazine (5...
Scheme 1: Three-component condensation of anilines, aldehydes and N,N-dimethylbarbituric acid. aReaction was ...
Figure 2: UV–vis absorption spectra of 5-arydeazaalloxazines 2f, 2j and 2n in DMF (l = 1 cm, c = 2.50 × 10−5 ...
Scheme 2: Control experiments related to bulky substituted aldehydes.
Beilstein J. Org. Chem. 2024, 20, 1308–1319, doi:10.3762/bjoc.20.114
Graphical Abstract
Figure 1: Reaction yields after seven uses of SSO and average recovery of the oil.
Scheme 1: Synthesis of epoxyisoindole-7-carboxylic acids 2a–m and 2n–p.
Scheme 2: Possible side reactions of unsaturated fatty acids with maleic anhydride.
Figure 2: Coupling constants of selected protons in compound 2a and its optimized geometric structure.
Scheme 3: Equilibrium of 2n–p with maleamic acid precursors.
Figure 3: Possible mechanism for the IMDAF reaction.
Figure 4: IRC calculations of a) endo-, b) exo-transition structures and products for compound 2a (semi-empir...
Beilstein J. Org. Chem. 2024, 20, 497–503, doi:10.3762/bjoc.20.44
Graphical Abstract
Figure 1: Neighbor-joining tree based on 16S rRNA gene sequences between KR21-0001 and members of the genus S...
Scheme 1: Fermentation of Saccharopolyspora sp. KR21-0001 and isolation procedure of KR21-0001A (1).
Figure 2: Structure of KR21-0001A (1). (a) 1H,1H COSY and HMBC correlations and (b) absolute configuration.
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...
Beilstein J. Org. Chem. 2023, 19, 1259–1288, doi:10.3762/bjoc.19.94
Graphical Abstract
Scheme 1: Research progress of coupling reactions and active compounds containing α-C(sp3)-functionalized eth...
Scheme 2: Transition-metal-catalyzed CDC pathways.
Scheme 3: CDC of active methylene compounds in the α-C(sp3) position of ethers.
Scheme 4: InCl3/Cu(OTf)2/NHPI co-catalyzed CDC reaction.
Scheme 5: CDC of cyclic benzyl ethers with aldehydes.
Scheme 6: Cu-catalyzed CDC of (a) unactivated C(sp3)–H ethers with simple ketones and (b) double C(sp3)−H fun...
Scheme 7: Cu-catalyzed CDC of C(sp3)–H/C(sp3)–H bonds.
Scheme 8: Cu-catalyzed synthesis of chiral 2-substituted tetrahydropyrans.
Scheme 9: CDC of thiazole with cyclic ethers.
Scheme 10: Cu(I)-catalyzed oxidative alkenylation of simple ethers.
Scheme 11: Cross-dehydrogenation coupling of isochroman C(sp3)–H bonds with anisole C(sp2)–H bonds.
Scheme 12: Pd(OAc)2/Cu(OTf)2-catalyzed arylation of α-C(sp3)–H bonds of ethers.
Scheme 13: Cu-catalyzed C(sp3)–H/C(sp2)–H activation strategies to construct C(sp3)–C(sp2) bonds.
Scheme 14: Cu(I)-catalyzed C(sp2)–H alkylation.
Scheme 15: Cu-catalyzed C(sp3)–H/C(sp)–H activation to construct C(sp3)–C(sp) bonds (H2BIP: 2,6-bis(benzimidaz...
Scheme 16: Fe-catalyzed CDC reaction pathways.
Scheme 17: Fe2(CO)9-catalyzed functionalization of C–H bonds.
Scheme 18: Ligand-promoted Fe-catalyzed CDC reaction of N-methylaniline with ethers.
Scheme 19: Fe-catalyzed CDC of C(sp3)–H/C(sp3)–H bonds.
Scheme 20: Fe-catalyzed hydroalkylation of α,β-unsaturated ketones with ethers.
Scheme 21: Solvent-free Fe(NO3)3-catalyzed CDC of C(sp3)–H/C(sp2)–H bonds.
Scheme 22: Alkylation of disulfide compounds to afford tetrasubstituted alkenes.
Scheme 23: Fe-catalyzed formation of 1,1-bis-indolylmethane derivatives.
Scheme 24: Alkylation of coumarins and flavonoids.
Scheme 25: Direct CDC α-arylation of azoles with ethers.
Scheme 26: CDC of terminal alkynes with C(sp3)–H bonds adjacent to oxygen, sulfur or nitrogen atoms.
Scheme 27: Alkylation of terminal alkynes.
Scheme 28: Co-catalyzed functionalization of glycine esters.
Scheme 29: Co-catalyzed construction of C(sp2)–C(sp3) bonds.
Scheme 30: Co-catalyzed CDC of imidazo[1,2-a]pyridines with isochroman.
Scheme 31: Co-catalyzed C–H alkylation of (benz)oxazoles with ethers.
Scheme 32: Cobalt-catalyzed CDC between unactivated C(sp2)–H and C(sp3)–H bonds.
Scheme 33: MnO2-catalyzed CDC of the inactive C(sp3)-H.
Scheme 34: Oxidative cross-coupling of ethers with enamides.
Scheme 35: Ni(II)-catalyzed CDC of indoles with 1,4-dioxane.
Scheme 36: Chemo- and regioselective ortho- or para-alkylation of pyridines.
Scheme 37: Asymmetric CDC of 3,6-dihydro-2H-pyrans with aldehydes.
Scheme 38: CDC of heterocyclic aromatics with ethers.
Scheme 39: Indium-catalyzed alkylation of DHPs with 1,3-dicarbonyl compounds.
Scheme 40: Rare earth-metal-catalyzed CDC reaction.
Scheme 41: Visible-light-driven CDC of cycloalkanes with benzazoles.
Scheme 42: Photoinduced alkylation of quinoline with cyclic ethers.
Scheme 43: Photocatalyzed CDC reactions between α-C(sp3)–H bonds of ethers and C(sp2)–H bonds of aromatics.
Beilstein J. Org. Chem. 2023, 19, 1243–1250, doi:10.3762/bjoc.19.92
Graphical Abstract
Scheme 1: Original triple organocatalytic cascade reaction developed by Enders.
Figure 1: Approaches based on the original Enders cascade reaction to access trisubstituted cyclohexene carba...
Scheme 2: Acetaldehyde dimethyl acetal (6) as an acetaldehyde surrogate to effect a triple organocatalytic ca...
Figure 2: Scope of the cascade reaction using 6 as an acetaldehyde equivalent. Reaction conditions: 3 (0.5 mm...
Beilstein J. Org. Chem. 2023, 19, 991–997, doi:10.3762/bjoc.19.74
Graphical Abstract
Figure 1: Examples of natural and bioactive hydrogenated furo[3,2-c]pyridines.
Scheme 1: The described approaches to tetrahydrofuro[3,2-c]pyridines and our work.
Scheme 2: The synthesis of tetrahydrofuro[3,2-c]pyridines 4. Conditions: athe reaction was performed at 1 mmo...
Scheme 3: The acid-catalyzed reversible transformation of tetrahydrofuro[3,2-c]pyridine 4a and 3-(2-oxopropyl...
Scheme 4: Synthesis of tetrahydropyrrolo[3,2-c]pyridine 6a.
Scheme 5: Reactivity of tetrahydrofuro[3,2-c]pyridine 4a.
Beilstein J. Org. Chem. 2023, 19, 593–634, doi:10.3762/bjoc.19.44
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...
Beilstein J. Org. Chem. 2023, 19, 380–398, doi:10.3762/bjoc.19.30
Graphical Abstract
Figure 1: Hypothetical interactions between the β-cyclodextrin host and guest molecules (flavonoid glycoside/...
Figure 2: Superposition of the FTIR spectra for the β-cyclodextrin/Corylus avellana oil/hesperidin ternary co...
Figure 3: Superposition of the FTIR spectra for the β-cyclodextrin/Corylus avellana oil/hesperidin ternary co...
Figure 4: PC2 versus PC1 scores plot from the FTIR–PCA analysis of the flavonoid glycoside and flavonolignan ...
Figure 5: PC2 versus PC1 scores plot from the FTIR–PCA analysis of the β-CD/hazelnut oil/flavonoid ternary co...
Figure 6: PC2 versus PC1 scores plot from the FTIR–PCA analysis of the β-CD/hazelnut oil/flavonoid ternary co...
Figure 7: PC2 versus PC1 scores plot from the FTIR–PCA analysis of the β-CD/hazelnut oil/flavonoid ternary co...
Figure 8: PC3 versus PC1 scores plot from the FTIR-PCA analysis of the β-CD/hazelnut oil/flavonoid ternary co...
Figure 9: PC3 versus PC2 scores plot from the FTIR–PCA analysis of the β-CD/hazelnut oil/flavonoid ternary co...
Figure 10: PC2 versus PC1 loadings plot from the FTIR–PCA analysis of the β-CD/hazelnut oil/flavonoid ternary ...
Figure 11: PC3 versus PC1 loadings plot from the FTIR–PCA analysis of the β-CD/hazelnut oil/flavonoid ternary ...
Figure 12: Eigenvalues of the correlation matrix from the FTIR–PCA analysis of the β-CD/hazelnut oil/flavonoid...
Beilstein J. Org. Chem. 2023, 19, 1–26, doi:10.3762/bjoc.19.1
Graphical Abstract
Scheme 1: The power of radical retrosynthesis and the tactic of divergent total synthesis.
Figure 1: Evolution of radical chemistry for organic synthesis.
Scheme 2: Divergent total synthesis of α-pyrone-diterpenoids (Baran).
Scheme 3: Divergent synthesis of pyrone diterpenoids by merged chemoenzymatic and radical synthesis (part I, ...
Scheme 4: Divergent synthesis of pyrone diterpenoids by merged chemoenzymatic and radical synthesis (part II,...
Scheme 5: Divergent synthesis of drimane-type hydroquinone meroterpenoids (Li).
Scheme 6: Divergent synthesis of natural products isolated from Dysidea avara (Lu).
Scheme 7: Divergent synthesis of kaurene-type terpenoids (Lei).
Scheme 8: Divergent synthesis of 6-oxabicyclo[3.2.1]octane meroterpenoids (Lou).
Scheme 9: Divergent synthesis of crinipellins by radical-mediated Dowd–Backwith rearrangement (Xie and Ding).
Scheme 10: Divergent total synthesis of Galbulimima alkaloids (Shenvi).
Scheme 11: Divergent synthesis of eburnane alkaloids (Qin).
Scheme 12: Divergent synthesis of Aspidosperma alkaloids (Boger).
Scheme 13: Photoredox based synthesis of (−)-FR901483 (160) and (+)-TAN1251C (162, Gaunt).
Scheme 14: Divergent synthesis of bipolamines (Maimone).
Scheme 15: Flow chemistry divergency between aporphine and morphinandione alkaloids (Felpin).
Scheme 16: Divergent synthesis of pyrroloazocine natural products (Echavarren).
Scheme 17: Using TEMPO to stabilize radicals for the divergent synthesis of pyrroloindoline natural products (...
Scheme 18: Radical pathway for preparation of lignans (Zhu).
Scheme 19: Divergent synthesis of DBCOD lignans (Lumb).
Beilstein J. Org. Chem. 2022, 18, 1575–1588, doi:10.3762/bjoc.18.168
Graphical Abstract
Figure 1: Selected imidazole-based bioactive molecules.
Scheme 1: Formation of ethyl 2-cyano-2-(1,3-dihydro-2H-imidazole-2-ylidene)acetate derivatives via [3 + 2] cy...
Scheme 2: C–H/C–Li coupling reaction of 2H-imidazole 1-oxides with pentafluorophenyllithium.
Scheme 3: Transition-metal-free coupling reaction of 2H-imidazole 1-oxides with polyphenols. Reaction conditi...
Scheme 4: Halogenation reaction of 2-unsubstituted imidazole N-oxides using tosyl halogenides.
Scheme 5: Solvent-free chlorination reaction of imidazole N-oxides.
Scheme 6: Multicomponent reaction of imidazole N-oxides 28 with Meldrum’s acid (26) and aldehydes.
Scheme 7: Multicomponent reaction of imidazole N-oxides with CH-acids and aldehydes. Reaction conditions: aTh...
Scheme 8: Three-component condensation reaction of imidazole N-oxides, arylglyoxals, and CH-acids 38 (dimedon...
Scheme 9: Synthesis of imidazole-2-thiones containing cyclohexyl-substituents at 3-position.
Scheme 10: Preparation of optically active derivatives of 3-butoxyimidazole-2-thione.
Beilstein J. Org. Chem. 2022, 18, 1140–1153, doi:10.3762/bjoc.18.118
Graphical Abstract
Figure 1: Structure of naturally occurring and synthetic 2-pyrrolidone derivatives.
Figure 2: Structure of natural compounds containing a 1,5-dihydro-2H-pyrrol-2-one subunit.
Scheme 1: Synthesis of substituted 4-acetyl-3-hydroxy-3-pyrroline-2-ones 4 via three-component reaction.
Scheme 2: Proposed mechanistic path for the synthesis of substituted 4-acetyl-3-hydroxy-3-pyrroline-2-ones.
Scheme 3: Tautomerism of compounds 4a–c in DMSO.
Figure 3: View of the molecular structure of compound 10aa with atom labeling. Displacement ellipsoids are dr...
Figure 4: The PES of reaction for the synthesis of 1,4,5-trisubstituted pyrrolidine-2,3-dione 10ab enamine de...
Scheme 4: Reaction pathways from 4a, 4a’ to 10ab via IS5 in the gase phase.
Scheme 5: Reaction pathways from 4a to 10ab-v2 via IS3 in the gase phase.
Figure 5: The PES for the possible pathways (1), (2), (3), and (4) in ethanol solvent.
Figure 6: The optimized structures of some reactants, intermediates, transition states, and products in the p...
Beilstein J. Org. Chem. 2022, 18, 769–780, doi:10.3762/bjoc.18.77
Graphical Abstract
Scheme 1: Early studies concerning cyclopropene cycloadditions to azomethine ylides and cycloaddition reactio...
Scheme 2: The pilot experiment aimed at studying the cycloaddition reaction between the protonated form of Ru...
Scheme 3: Synthesis of meso-3'-azadispiro[indene-2,2'-bicyclo[3.1.0]hexane-4',2''-indene] derivatives 3b–g vi...
Figure 1: ORTEP representation of the molecular structure of 3e.
Scheme 4: The reaction of protonated Ruhemann's purple (1) with 3-methyl-3-phenylcyclopropene (2j).
Scheme 5: Attempts to carry out the cycloaddition reactions between 3,3-disubstituted cyclopropenes 2k,l and ...
Scheme 6: The reactions of protonated Ruhemann's purple (1) with unstable cyclopropenes 2m–p.
Scheme 7: The acid–base reaction of Ruhemann's purple with hydrochloric acid and relative Gibbs free energy c...
Scheme 8: Plausible mechanism of the 1,3-DC reaction of protonated Ruhemann's purple (1) with 3-methyl-3-phen...
Scheme 9: Plausible mechanism of the 1,3-DC reaction of protonated Ruhemann's purple (1) with 1-chloro-2-phen...
Beilstein J. Org. Chem. 2021, 17, 2787–2794, doi:10.3762/bjoc.17.189
Graphical Abstract
Figure 1: Pyrrolo[1,2-a]quinazoline derivatives – analogs of vasicinone alkaloids and their biological activi...
Scheme 1: Synthetic approaches to 2,3-dihydropyrrolo[1,2-a]quinazolin-5(1H)-one derivatives.
Scheme 2: Plausible mechanism for the formation of 6.
Figure 2: X-ray crystal structure of compound 6f.
Beilstein J. Org. Chem. 2021, 17, 2629–2641, doi:10.3762/bjoc.17.176
Graphical Abstract
Figure 1: Catalyst design principles.
Scheme 1: Synthesis of isothiocyanate 3a and isocyanate 3b.
Scheme 2: Synthesis of sulfinylthioureas C1 and ureas C2.
Scheme 3: Synthesis of adducts 8a,d,f in solution.
Figure 2: DFT-calculated (PBEh-3c/def2-SV(P)//M06-2X/def2-TZVP) structures of catalyst (S,R) and (S,S)-C2, en...
Figure 3: a) Arrangements of reactants in the transition states; b) DFT-calculated (PBEh-3c/def2-SV(P)//M06-2...
Figure 4: DFT-calculated (PBEh-3c/def2-SV(P)//M06-2X/def2-TZVP) reaction profile for the Michael addition of ...
Beilstein J. Org. Chem. 2021, 17, 2462–2476, doi:10.3762/bjoc.17.163
Graphical Abstract
Scheme 1: Ag/I2-mediated electrophilic annulation of 2-en-4-ynyl azides 1.
Scheme 2: The proposed mechanism of Ag-catalyzed aza-annulation.
Scheme 3: The proposed mechanism of I2-mediated aza-annulation.
Scheme 4: Copper-catalyzed amination of (E)-2-en-4-ynyl azides 1.
Scheme 5: The proposed mechanism of copper-catalyzed amination.
Scheme 6: The derivatization of sulfonated aminonicotinates.
Scheme 7: Copper-catalyzed chalcogenoamination of (E)-2-en-4-ynyl azides 1.
Scheme 8: The possible mechanism of chalcogenoamination.
Scheme 9: The derivatization of 5‑selenyl- and 5-sulfenyl-substituted nicotinates.
Scheme 10: The tandem reaction of nitriles, Reformatsky reagents, and 1,3-enynes.
Scheme 11: Nickel-catalyzed [4 + 2]-cycloaddition of 3-azetidinones with 1,3-enynes.
Scheme 12: Electrophilic iodocyclization of 2-nitro-1,3-enynes to pyrroles.
Scheme 13: Electrophilic halogenation of 2-trifluoromethyl-1,3-enynes to pyrroles.
Scheme 14: Copper-catalyzed cascade cyclization of 2-nitro-1,3-enynes with amines.
Scheme 15: Tandem cyclization of 2-nitro-1,3-enynes, Togni reagent II, and amines.
Scheme 16: Tandem cyclization of 2-nitro-1,3-enynes, TMSN3, and amines.
Scheme 17: Cascade cyclization of 6-hydroxyhex-2-en-4-ynals to pyrroles.
Scheme 18: Au/Ag-catalyzed oxidative aza-annulation of 1,3-enynyl azides.
Scheme 19: The plausible mechanism of Au/Ag-catalyzed oxidative aza-annulation.
Scheme 20: Synthesis of 2-tetrazolyl-substituted 3-acylpyrroles from enynals.
Scheme 21: CuH-catalyzed coupling reaction of 1,3-enynes and nitriles to pyrroles.
Scheme 22: The mechanism of CuH-catalyzed coupling of 1,3-enynes and nitriles to pyrroles.
Beilstein J. Org. Chem. 2021, 17, 1981–2025, doi:10.3762/bjoc.17.129
Graphical Abstract
Figure 1: Overview of the methods available for the synthesis of polysaccharides. For each method, advantages...
Figure 2: Overview of the classes of polysaccharides discussed in this review. Each section deals with polysa...
Scheme 1: Enzymatic and chemical polymerization approaches provide cellulose oligomers with a non-uniform dis...
Scheme 2: AGA of a collection of cellulose analogues obtained using BBs 6–9. Specifically placed modification...
Figure 3: Chemical structure of the different branches G, X, L, F commonly found in XGs. Names are given foll...
Scheme 3: AGA of XG analogues with defined side chains. The AGA cycle includes coupling (TMSOTf), Fmoc deprot...
Figure 4: Synthetic strategies and issues associated to the formation of the β(1–3) linkage.
Scheme 4: Convergent synthesis of β(1–3)-glucans using a regioselective glycosylation strategy.
Scheme 5: DMF-mediated 1,2-cis glycosylation. A) General mechanism and B) examples of α-glucans prepared usin...
Scheme 6: Synergistic glycosylation strategy employing a nucleophilic modulation strategy (TMSI and Ph3PO) in...
Scheme 7: Different approaches to produce xylans. A) Polymerization techniques including ROP, and B) enzymati...
Scheme 8: A) Synthesis of arabinofuranosyl-decorated xylan oligosaccharides using AGA. Representative compoun...
Scheme 9: Chemoenzymatic synthesis of COS utilizing a lysozyme-catalyzed transglycosylation reaction followed...
Scheme 10: Synthesis of COS using an orthogonal glycosylation strategy based on the use of two different LGs.
Scheme 11: Orthogonal N-PGs permitted the synthesis of COS with different PA.
Scheme 12: AGA of well-defined COS with different PA using two orthogonally protected BBs. The AGA cycle inclu...
Scheme 13: A) AGA of β(1–6)-N-acetylglucosamine hexasaccharide and dodecasaccharide. AGA includes cycles of co...
Figure 5: ‘Double-faced’ chemistry exemplified for ᴅ-Man and ʟ-Rha. Constructing β-Man linkages is considerab...
Figure 6: Implementation of a capping step after each glycosylation cycle for the AGA of a 50mer oligomannosi...
Scheme 14: AGA enabled the synthesis of a linear α(1–6)-mannoside 100mer 93 within 188 h and with an average s...
Scheme 15: The 151mer branched polymannoside was synthesized by a [30 + 30 + 30 + 30 + 31] fragment coupling. ...
Figure 7: PG stereocontrol strategy to obtain β-mannosides. A) The mechanism of the β-mannosylation reaction ...
Scheme 16: A) Mechanism of 1,2-cis stereoselective glycosylation using ManA donors. Once the ManA donor is act...
Figure 8: A) The preferred 4H3 conformation of the gulosyl oxocarbenium ion favors the attack of the alcohol ...
Scheme 17: AGA of type I rhamnans up to 16mer using disaccharide BB 115 and CNPiv PG. The AGA cycle includes c...
Figure 9: Key BBs for the synthesis of the O-antigen of Bacteroides vulgatus up to a 128mer (A) and the CPS o...
Figure 10: Examples of type I and type II galactans synthesized to date.
Figure 11: A) The DTBS PG stabilizes the 3H4 conformation of the Gal oxocarbenium ion favoring the attack of t...
Figure 12: Homogalacturonan oligosaccharides synthesized to date. Access to different patterns of methyl-ester...
Figure 13: GlfT2 from Mycobacterium tuberculosis catalyzes the sequential addition of UPD-Galf donor to a grow...
Figure 14: The poor reactivity of acceptor 137 hindered a stepwise synthesis of the linear galactan backbone a...
Scheme 18: AGA of a linear β(1–5) and β(1–6)-linked galactan 20mer. The AGA cycle includes coupling (NIS/TfOH)...
Figure 15: The 92mer arabinogalactan was synthesized using a [31 + 31 + 30] fragment coupling between a 31mer ...
Scheme 19: Synthesis of the branched arabinofuranose fragment using a six component one-pot synthesis. i) TTBP...
Figure 16: A) Chemical structure and SNFG of the representative disaccharide units forming the GAG backbones, ...
Figure 17: Synthetic challenges associated to the H/HS synthesis.
Scheme 20: Degradation of natural heparin and heparosan generated valuable disaccharides 150 and 151 that can ...
Scheme 21: A) The one-step conversion of cyanohydrin 156 to ʟ-iduronamide 157 represent the key step for the s...
Scheme 22: A) Chemoenzymatic synthesis of heparin structures, using different types of UDP activated natural a...
Scheme 23: Synthesis of the longest synthetic CS chain 181 (24mer) using donor 179 and acceptor 180 in an iter...
Scheme 24: AGA of a collection of HA with different lengths. The AGA cycle includes coupling (TfOH) and Lev de...
Beilstein J. Org. Chem. 2021, 17, 1849–1938, doi:10.3762/bjoc.17.126
Graphical Abstract
Scheme 1: Schematic overview of transition metals studied in C–H activation processes.
Scheme 2: (A) Known biological activities related to benzimidazole-based compounds; (B and C) an example of a...
Scheme 3: (A) Known biological activities related to quinoline-based compounds; (B and C) an example of a sca...
Scheme 4: (A) Known biological activities related to sulfur-containing compounds; (B and C) an example of a s...
Scheme 5: (A) Known biological activities related to aminoindane derivatives; (B and C) an example of a scand...
Scheme 6: (A) Known biological activities related to norbornane derivatives; (B and C) an example of a scandi...
Scheme 7: (A) Known biological activities related to aniline derivatives; (B and C) an example of a titanium-...
Scheme 8: (A) Known biological activities related to cyclohexylamine derivatives; (B) an example of an intram...
Scheme 9: (A) Known biologically active benzophenone derivatives; (B and C) photocatalytic oxidation of benzy...
Scheme 10: (A) Known bioactive fluorine-containing compounds; (B and C) vanadium-mediated C(sp3)–H fluorinatio...
Scheme 11: (A) Known biologically active Lythraceae alkaloids; (B) synthesis of (±)-decinine (30).
Scheme 12: (A) Synthesis of (R)- and (S)-boehmeriasin (31); (B) synthesis of phenanthroindolizidines by vanadi...
Scheme 13: (A) Known bioactive BINOL derivatives; (B and C) vanadium-mediated oxidative coupling of 2-naphthol...
Scheme 14: (A) Known antiplasmodial imidazopyridazines; (B) practical synthesis of 41.
Scheme 15: (A) Gold-catalyzed drug-release mechanism using 2-alkynylbenzamides; (B and C) chromium-mediated al...
Scheme 16: (A) Examples of anti-inflammatory benzaldehyde derivatives; (B and C) chromium-mediated difunctiona...
Scheme 17: (A and B) Manganese-catalyzed chemoselective intramolecular C(sp3)–H amination; (C) late-stage modi...
Scheme 18: (A and B) Manganese-catalyzed C(sp3)–H amination; (C) late-stage modification of a leelamine deriva...
Scheme 19: (A) Known bioactive compounds containing substituted N-heterocycles; (B and C) manganese-catalyzed ...
Scheme 20: (A) Known indoles that present GPR40 full agonist activity; (B and C) manganese-catalyzed C–H alkyl...
Scheme 21: (A) Examples of known biaryl-containing drugs; (B and C) manganese-catalyzed C–H arylation through ...
Scheme 22: (A) Known zidovudine derivatives with potent anti-HIV properties; (B and C) manganese-catalyzed C–H...
Scheme 23: (A and B) Manganese-catalyzed C–H organic photo-electrosynthesis; (C) late-stage modification.
Scheme 24: (A) Example of a known antibacterial silylated dendrimer; (B and C) manganese-catalyzed C–H silylat...
Scheme 25: (A and B) Fe-based small molecule catalyst applied for selective aliphatic C–H oxidations; (C) late...
Scheme 26: (A) Examples of naturally occurring gracilioethers; (B) the first total synthesis of gracilioether ...
Scheme 27: (A and B) Selective aliphatic C–H oxidation of amino acids; (C) late-stage modification of proline-...
Scheme 28: (A) Examples of Illicium sesquiterpenes; (B) first chemical synthesis of (+)-pseudoanisatin (80) in...
Scheme 29: (A and B) Fe-catalyzed deuteration; (C) late-stage modification of pharmaceuticals.
Scheme 30: (A and B) Biomimetic Fe-catalyzed aerobic oxidation of methylarenes to benzaldehydes (PMHS, polymet...
Scheme 31: (A) Known tetrahydroquinolines with potential biological activities; (B and C) redox-selective Fe c...
Scheme 32: (A) Known drugs containing a benzofuran unit; (B and C) Fe/Cu-catalyzed tandem O-arylation to acces...
Scheme 33: (A) Known azaindolines that act as M4 muscarinic acetylcholine receptor agonists; (B and C) intramo...
Scheme 34: (A) Known indolinones with anticholinesterase activity; (B and C) oxidative C(sp3)–H cross coupling...
Scheme 35: (A and B) Cobalt-catalyzed C–H alkenylation of C-3-peptide-containing indoles; (C) derivatization b...
Scheme 36: (A) Cobalt-Cp*-catalyzed C–H methylation of known drugs; (B and C) scope of the o-methylated deriva...
Scheme 37: (A) Known lasalocid A analogues; (B and C) three-component cobalt-catalyzed C–H bond addition; (D) ...
Scheme 38: (A and B) Cobalt-catalyzed C(sp2)–H amidation of thiostrepton.
Scheme 39: (A) Known 4H-benzo[d][1,3]oxazin-4-one derivatives with hypolipidemic activity; (B and C) cobalt-ca...
Scheme 40: (A and B) Cobalt-catalyzed C–H arylation of pyrrole derivatives; (C) application for the synthesis ...
Scheme 41: (A) Known 2-phenoxypyridine derivatives with potent herbicidal activity; (B and C) cobalt-catalyzed...
Scheme 42: (A) Natural cinnamic acid derivatives; (B and C) cobalt-catalyzed C–H carboxylation of terminal alk...
Scheme 43: (A and B) Cobalt-catalyzed C–H borylation; (C) application to the synthesis of flurbiprofen.
Scheme 44: (A) Benzothiazoles known to present anticonvulsant activities; (B and C) cobalt/ruthenium-catalyzed...
Scheme 45: (A and B) Cobalt-catalyzed oxygenation of methylene groups towards ketone synthesis; (C) synthesis ...
Scheme 46: (A) Known anticancer tetralone derivatives; (B and C) cobalt-catalyzed C–H difluoroalkylation of ar...
Scheme 47: (A and B) Cobalt-catalyzed C–H thiolation; (C) application in the synthesis of quetiapine (153).
Scheme 48: (A) Known benzoxazole derivatives with anticancer, antifungal, and antibacterial activities; (B and...
Scheme 49: (A and B) Cobalt-catalyzed C–H carbonylation of naphthylamides; (C) BET inhibitors 158 and 159 tota...
Scheme 50: (A) Known bioactive pyrrolo[1,2-a]quinoxalin-4(5H)-one derivatives; (B and C) cobalt-catalyzed C–H ...
Scheme 51: (A) Known antibacterial cyclic sulfonamides; (B and C) cobalt-catalyzed C–H amination of propargyli...
Scheme 52: (A and B) Cobalt-catalyzed intramolecular 1,5-C(sp3)–H amination; (C) late-stage functionalization ...
Scheme 53: (A and B) Cobalt-catalyzed C–H/C–H cross-coupling between benzamides and oximes; (C) late-state syn...
Scheme 54: (A) Known anticancer natural isoquinoline derivatives; (B and C) cobalt-catalyzed C(sp2)–H annulati...
Scheme 55: (A) Enantioselective intramolecular nickel-catalyzed C–H activation; (B) bioactive obtained motifs;...
Scheme 56: (A and B) Nickel-catalyzed α-C(sp3)–H arylation of ketones; (C) application of the method using kno...
Scheme 57: (A and B) Nickel-catalyzed C(sp3)–H acylation of pyrrolidine derivatives; (C) exploring the use of ...
Scheme 58: (A) Nickel-catalyzed C(sp3)–H arylation of dioxolane; (B) library of products obtained from biologi...
Scheme 59: (A) Intramolecular enantioselective nickel-catalyzed C–H cycloalkylation; (B) product examples, inc...
Scheme 60: (A and B) Nickel-catalyzed C–H deoxy-arylation of azole derivatives; (C) late-stage functionalizati...
Scheme 61: (A and B) Nickel-catalyzed decarbonylative C–H arylation of azole derivatives; (C) application of t...
Scheme 62: (A and B) Another important example of nickel-catalyzed C–H arylation of azole derivatives; (C) app...
Scheme 63: (A and B) Another notable example of a nickel-catalyzed C–H arylation of azole derivatives; (C) lat...
Scheme 64: (A and B) Nickel-based metalorganic framework (MOF-74-Ni)-catalyzed C–H arylation of azole derivati...
Scheme 65: (A) Known commercially available benzothiophene-based drugs; (B and C) nickel-catalyzed C–H arylati...
Scheme 66: (A) Known natural tetrahydrofuran-containing substances; (B and C) nickel-catalyzed photoredox C(sp3...
Scheme 67: (A and B) Another notable example of a nickel-catalyzed photoredox C(sp3)–H alkylation/arylation; (...
Scheme 68: (A) Electrochemical/nickel-catalyzed C–H alkoxylation; (B) achieved scope, including three using na...
Scheme 69: (A) Enantioselective photoredox/nickel catalyzed C(sp3)–H arylation; (B) achieved scope, including ...
Scheme 70: (A) Known commercially available trifluoromethylated drugs; (B and C) nickel-catalyzed C–H trifluor...
Scheme 71: (A and B) Stereoselective nickel-catalyzed C–H difluoroalkylation; (C) late-stage functionalization...
Scheme 72: (A) Cu-mediated ortho-amination of oxalamides; (B) achieved scope, including derivatives obtained f...
Scheme 73: (A) Electro-oxidative copper-mediated amination of 8-aminoquinoline-derived amides; (B) achieved sc...
Scheme 74: (A and B) Cu(I)-mediated C–H amination with oximes; (C) derivatization using telmisartan (241) as s...
Scheme 75: (A and B) Cu-mediated amination of aryl amides using ammonia; (C) late-stage modification of proben...
Scheme 76: (A and B) Synthesis of purine nucleoside analogues using copper-mediated C(sp2)–H activation.
Scheme 77: (A) Copper-mediated annulation of acrylamide; (B) achieved scope, including the synthesis of the co...
Scheme 78: (A) Known bioactive compounds containing a naphthyl aryl ether motif; (B and C) copper-mediated eth...
Scheme 79: (A and B) Cu-mediated alkylation of N-oxide-heteroarenes; (C) late-stage modification.
Scheme 80: (A) Cu-mediated cross-dehydrogenative coupling of polyfluoroarenes and alkanes; (B) scope from know...
Scheme 81: (A) Known anticancer acrylonitrile compounds; (B and C) Copper-mediated cyanation of unactivated al...
Scheme 82: (A) Cu-mediated radiofluorination of 8-aminoquinoline-derived aryl amides; (B) achieved scope, incl...
Scheme 83: (A) Examples of natural β-carbolines; (B and C) an example of a zinc-catalyzed C–H functionalizatio...
Scheme 84: (A) Examples of anticancer α-aminophosphonic acid derivatives; (B and C) an example of a zinc-catal...
Beilstein J. Org. Chem. 2021, 17, 1814–1827, doi:10.3762/bjoc.17.124
Graphical Abstract
Figure 1: Schematic overview of fungal interactions in the environment. Fungi can be found in essentially all...
Figure 2: Fungal derived bioactive natural compounds with ecological and/or economic relevance.
Figure 3: Gliotoxin biosynthetic gene cluster and it major biosynthetic transformations: Gliotoxin (5) is the...
Figure 4: Amoebicidal secondary metabolites trypacidin and fumagillin of Aspergillus fumigatus.
Figure 5: Intermediates of the DHN-melanin biosynthesis in Aspergillus fumigatus.
Figure 6: Intermediates and products of the fumigaclavine C biosynthesis.
Figure 7: Bioactive secondary metabolites of Aspergillus fumigatus.
Figure 8: Helvolic acid gene cluster of A. fumigatus.
Beilstein J. Org. Chem. 2021, 17, 1752–1813, doi:10.3762/bjoc.17.123
Graphical Abstract
Scheme 1: Fluorination with N-F amine 1-1.
Scheme 2: Preparation of N-F amine 1-1.
Scheme 3: Reactions of N-F amine 1-1.
Scheme 4: Synthesis of N-F perfluoroimides 2-1 and 2-2.
Scheme 5: Synthesis of 1-fluoro-2-pyridone (3-1).
Scheme 6: Fluorination with 1-fluoro-2-pyridone (3-1).
Figure 1: Synthesis of N-F sulfonamides 4-1a–g.
Scheme 7: Fluorination with N-F reagent 4-1b,c,f.
Scheme 8: Fluorination of alkenyllithiums with N-F 4-1h.
Scheme 9: Synthesis of N-fluoropyridinium triflate (5-4a).
Scheme 10: Synthetic methods for N-F-pyridinium salts.
Figure 2: Synthesis of various N-fluoropyridinium salts. Note: athis yield was the one by the improved method...
Scheme 11: Fluorination power order of N-fluoropyridinium salts.
Scheme 12: Fluorinations with N-F salts 5-4.
Scheme 13: Fluorination of Corey lactone 5-7 with N-F-bis(methoxymethyl) salt 5-4l.
Scheme 14: Fluorination with NFPy.
Scheme 15: Synthesis of the N-F reagent, N-fluoroquinuclidinium fluoride (6-1).
Scheme 16: Fluorinations achieved with N-F fluoride 6-1.
Scheme 17: Synthesis of N-F imides 7-1a–g.
Scheme 18: Fluorination with (CF3SO2)2NF, 7-1a.
Scheme 19: Fluorination reactions of various substrates with 7-1a.
Scheme 20: Synthesis of N-F triflate 8-1.
Scheme 21: Synthesis of chiral N-fluoro sultams 9-1 and 9-2.
Scheme 22: Fluorination with chiral N-fluoro sultams 9-1 and 9-2.
Scheme 23: Synthesis of saccharin-derived N-fluorosultam 10-2.
Scheme 24: Fluorination with N-fluorosultam 10-2.
Scheme 25: Synthesis of N-F reagent 11-2.
Scheme 26: Fluorination with N-F reagent 11-2.
Scheme 27: Synthesis and reaction of N-fluorolactams 12-1.
Scheme 28: Synthesis of NFOBS 13-2.
Scheme 29: Fluorination with NFOBS 13-2.
Scheme 30: Synthesis of NFSI (14-2).
Scheme 31: Fluorination with NFSI 14-2.
Scheme 32: Synthesis of N-fluorosaccharin (15-1) and N-fluorophthalimide (15-2).
Scheme 33: Synthesis of N-F salts 16-3.
Scheme 34: Fluorination with N-F salts 16-3.
Figure 3: Monofluorination with Selectfluor (16-3a).
Figure 4: Difluorination with Selectfluor (16-3a).
Scheme 35: Transfer fluorination of Selectfluor (16-3a).
Scheme 36: Fluorination of substrates with Selectfluor (16-3a).
Scheme 37: Synthesis of chiral N-fluoro-sultam 17-2.
Scheme 38: Asymmetric fluorination with chiral 17-2.
Figure 5: Synthesis of Zwitterionic N-fluoropyridinium salts 18-2a–h.
Scheme 39: Fluorinating power order of zwitterionic N-fluoropyridinium salts.
Scheme 40: Fluorination with zwitterionic 18-2.
Scheme 41: Activation of salt 18-2h with TfOH.
Scheme 42: Synthesis of NFTh, 19-2.
Scheme 43: Fluorination with NFTh, 19-2.
Scheme 44: Synthesis of 3-fluorobenzo-1,2,3-oxathiazin-4-one 2,2-dioxide (20-2).
Scheme 45: Fluorination with 20-2.
Scheme 46: Synthesis of N-F amide 21-3.
Scheme 47: Fluorination with N-F amide 21-2.
Scheme 48: Synthesis of N,N’-difluorodiazoniabicyclo[2.2.2]octane salts 22-1.
Scheme 49: One-pot synthesis of N,N’-difluoro-1,4-diazoniabicyclo[2.2.2]octane bistetrafluoroborate salt (22-1d...
Figure 6: Fluorination of anisole with 22-1a, d, e.
Scheme 50: Fluorination with N,N’-diF bisBF4 22-1d.
Scheme 51: Synthesis of bis-N-F reagents 23-1–5.
Scheme 52: Fluorination with 23-2, 4, 5.
Figure 7: Synthesis of N,N’-difluorobipyridinium salts 24-2.
Figure 8: Controlled fluorination of N,N’-diF 24-2.
Scheme 53: Fluorinating power of N,N’-diF salts 24-2 and N-F salt 5-4a.
Scheme 54: Fluorination reactions with SynfluorTM (24-2b).
Scheme 55: Additional fluorination reactions with SynfluorTM (24-2b).
Scheme 56: Synthesis of N-F 25-1.
Scheme 57: Fluorination of polycyclic aromatics with 25-1.
Scheme 58: Synthesis of 26-1 and dimethyl analog 26-2.
Scheme 59: Fluorination with reagents 26-1, 26-2, 1-1, and 26-3.
Scheme 60: Synthesis of N-F reagent 27-2.
Scheme 61: Synthesis of chiral N-F reagents 27-6.
Scheme 62: Synthesis of chiral N-F 27-7–9.
Scheme 63: Asymmetric fluorination with 27-6.
Scheme 64: Synthesis of chiral N-F reagents 28-3.
Scheme 65: Asymmetric fluorination with 28-3.
Scheme 66: Synthesis of chiral N-F reagents 28-7.
Figure 9: Asymmetric fluorination with 28-7.
Scheme 67: In situ formation of N-fluorinated cinchona alkaloids with SelectfluorTM.
Scheme 68: Asymmetric fluorination with N-F alkaloids formed in situ.
Scheme 69: Synthesis of N-fluorocinchona alkaloids with Selectfluor.
Scheme 70: Asymmetric fluorination with 30-1–4.
Scheme 71: Transfer fluorination from various N-F reagents.
Figure 10: Asymmetric fluorination of silyl enol ethers.
Scheme 72: Synthesis of N-fluoro salt 32-2.
Scheme 73: Reactivity of N-fluorotriazinium salt 32-2.
Scheme 74: Synthesis of bulky N-fluorobenzenesulfonimide NFBSI 33-3.
Scheme 75: Comparison of NFSI and NFBSI.
Scheme 76: Synthesis of p-substituted N-fluorobenzenesulfonimides 34-3.
Figure 11: Asymmetric fluorination with 34-3 and a chiral catalyst 34-4.
Scheme 77: 1,4-Fluoroamination with Selecfluor and a chiral catalyst.
Figure 12: Asymmetric fluoroamination with 35-5a, b.
Scheme 78: Synthesis of Selectfluor analogs 35-5a, b.
Scheme 79: Synthesis of chiral dicationic DABCO-based N-F reagents 36-5.
Scheme 80: Asymmetric fluorocyclization with chiral 36-5b.
Scheme 81: Synthesis of chiral 37-2a,b.
Scheme 82: Asymmetric fluorination with chiral 37-2a,b.
Scheme 83: Asymmetric fluorination with chiral 37-2b.
Scheme 84: Reaction of indene with chiral 37-2a,b.
Scheme 85: Synthesis of Me-NFSI, 38-2.
Scheme 86: Fluorination of active methine compounds with Me-NFSI.
Scheme 87: Fluorination of malonates with Me-NFSI.
Scheme 88: Fluorination of keto esters with Me-NFSI.
Scheme 89: Synthesis of N-F 39-3 derived from the ethylene-bridged Tröger’s base.
Scheme 90: Fluorine transfer from N-F 39-3.
Scheme 91: Fluorination with N-F 39-3.
Scheme 92: Synthesis of SelectfluorCN.
Scheme 93: Bistrifluoromethoxylation of alkenes using SelectfluorCN.
Figure 13: Synthesis of NFAS 41-2.
Scheme 94: Radical fluorination with different N-F reagents.
Scheme 95: Radical fluorination of alkenes with NFAS 41-2.
Scheme 96: Radical fluorination of alkenes with NFAS 41-2f.
Scheme 97: Decarboxylative fluorination with NFAS 41-2a,f.
Scheme 98: Fluorine plus detachment (FPD).
Figure 14: FPD values of representative N-F reagents in CH2Cl2 and CH3CN (in parentheses). Adapted with permis...
Scheme 99: N-F homolytic bond dissociation energy (BDE).
Figure 15: BDE values of representative N-F reagents in CH3CN. Adapted with permission from ref. [127]. Copyright 2...
Figure 16: Quantitative reactivity scale for popular N-F reagents. Adapted with permission from ref. [138], publish...
Scheme 100: SET and SN2 mechanisms.
Scheme 101: Radical clock reactions.
Scheme 102: Reaction of potassium enolate of citronellic ester with N-F reagents, 10-1, NFSI, and 8-1.
Scheme 103: Reaction of compound IV with Selectfluor (OTf) and NFSI.
Scheme 104: Reaction of TEMPO with Selecfluor.
Beilstein J. Org. Chem. 2021, 17, 819–865, doi:10.3762/bjoc.17.71
Graphical Abstract
Figure 1: Marketed drugs with acridine moiety.
Scheme 1: Synthesis of 4-arylacridinediones.
Scheme 2: Proposed mechanism for acridinedione synthesis.
Scheme 3: Synthesis of tetrahydrodibenzoacridinones.
Scheme 4: Synthesis of naphthoacridines.
Scheme 5: Plausible mechanism for naphthoacridines.
Figure 2: Benzoazepines based potent molecules.
Scheme 6: Synthesis of azepinone.
Scheme 7: Proposed mechanism for azepinone formation.
Scheme 8: Synthesis of benzoazulenen-1-one derivatives.
Scheme 9: Proposed mechanism for benzoazulene-1-one synthesis.
Figure 3: Indole-containing pharmacologically active molecules.
Scheme 10: Synthesis of functionalized indoles.
Scheme 11: Plausible mechanism for the synthesis of functionalized indoles.
Scheme 12: Synthesis of spirooxindoles.
Scheme 13: Synthesis of substituted spirooxindoles.
Scheme 14: Plausible mechanism for the synthesis of substituted spirooxindoles.
Scheme 15: Synthesis of pyrrolidinyl spirooxindoles.
Scheme 16: Proposed mechanism for pyrrolidinyl spirooxindoles.
Figure 4: Pyran-containing biologically active molecules.
Scheme 17: Synthesis of functionalized benzopyrans.
Scheme 18: Plausible mechanism for synthesis of benzopyran.
Scheme 19: Synthesis of indoline-spiro-fused pyran derivatives.
Scheme 20: Proposed mechanism for indoline-spiro-fused pyran.
Scheme 21: Synthesis of substituted naphthopyrans.
Figure 5: Marketed drugs with pyrrole ring.
Scheme 22: Synthesis of tetra-substituted pyrroles.
Scheme 23: Mechanism for silica-supported PPA-SiO2-catalyzed pyrrole synthesis.
Scheme 24: Synthesis of pyrrolo[1,10]-phenanthrolines.
Scheme 25: Proposed mechanism for pyrrolo[1,10]-phenanthrolines.
Figure 6: Marketed drugs and molecules containing pyrimidine and pyrimidinones skeletons.
Scheme 26: MWA-MCR pyrimidinone synthesis.
Scheme 27: Two proposed mechanisms for pyrimidinone synthesis.
Scheme 28: MWA multicomponent synthesis of dihydropyrimidinones.
Scheme 29: Proposed mechanism for dihydropyrimidinones.
Figure 7: Biologically active fused pyrimidines.
Scheme 30: MWA- MCR for the synthesis of pyrrolo[2,3-d]pyrimidines.
Scheme 31: Proposed mechanism for pyrrolo[2,3-d]pyrimidines.
Scheme 32: Synthesis of substituted pyrrolo[2,3-d]pyrimidine-2,4-diones.
Scheme 33: Probable pathway for pyrrolo[2,3-d]pyrimidine-2,4-diones.
Scheme 34: Synthesis of pyridopyrimidines.
Scheme 35: Plausible mechanism for the synthesis of pyridopyrimidines.
Scheme 36: Synthesis of dihydropyridopyrimidine and dihydropyrazolopyridine.
Scheme 37: Proposed mechanism for the formation of dihydropyridopyrimidine.
Scheme 38: Synthesis of thiopyrano[4,3-d]pyrimidines.
Scheme 39: Plausible mechanism for the synthesis of thiopyrano[4,3-d]pyrimidines.
Scheme 40: Synthesis of decorated imidazopyrimidines.
Scheme 41: Proposed mechanism for imidazopyrimidine synthesis.
Figure 8: Pharmacologically active molecules containing purine bases.
Scheme 42: Synthesis of aza-adenines.
Scheme 43: Synthesis of 5-aza-7-deazapurines.
Scheme 44: Proposed mechanism for deazapurines synthesis.
Figure 9: Biologically active molecules containing pyridine moiety.
Scheme 45: Synthesis of steroidal pyridines.
Scheme 46: Proposed mechanism for steroidal pyridine.
Scheme 47: Synthesis of N-alkylated 2-pyridones.
Scheme 48: Two possible mechanisms for pyridone synthesis.
Scheme 49: Synthesis of pyridone derivatives.
Scheme 50: Postulated mechanism for synthesis of pyridone.
Figure 10: Biologically active fused pyridines.
Scheme 51: Benzimidazole-imidazo[1,2-a]pyridines synthesis.
Scheme 52: Mechanism for the synthesis of benzimidazole-imidazo[1,2-a]pyridines.
Scheme 53: Synthesis of pyrazolo[3,4-b]pyridine-5-spirocycloalkanedione derivatives.
Scheme 54: Proposed mechanism for spiro-pyridines.
Scheme 55: Functionalized macrocyclane-fused pyrazolo[3,4-b]pyridine derivatives.
Scheme 56: Mechanism postulated for macrocyclane-fused pyrazolo[3,4-b]pyridine.
Scheme 57: Generation of pyrazolo[3,4-b]pyridines.
Scheme 58: Proposed mechanism for the synthesis of pyrazolo[3,4-b]pyridines.
Scheme 59: Proposed mechanism for the synthesis of azepinoindole.
Figure 11: Pharmaceutically important molecules with quinoline moiety.
Scheme 60: Povarov-mediated quinoline synthesis.
Scheme 61: Proposed mechanism for Povarov reaction.
Scheme 62: Synthesis of pyrazoloquinoline.
Scheme 63: Plausible mechanism for pyrazoloquinoline synthesis.
Figure 12: Quinazolinones as pharmacologically significant scaffolds.
Scheme 64: Four-component reaction for dihydroquinazolinone.
Scheme 65: Proposed mechanism for dihydroquinazolinones.
Scheme 66: Synthesis purine quinazolinone and PI3K-δ inhibitor.
Scheme 67: Synthesis of fused benzothiazolo/benzoimidazoloquinazolinones.
Scheme 68: Proposed mechanism for fused benzothiazolo/benzoimidazoloquinazolinones.
Scheme 69: On-water reaction for synthesis of thiazoloquinazolinone.
Scheme 70: Proposed mechanism for the thiazoloquinazolinone synthesis.
Scheme 71: β-Cyclodextrin-mediated synthesis of indoloquinazolinediones.
Scheme 72: Proposed mechanism for synthesis of indoloquinazolinediones.
Figure 13: Triazoles-containing marketted drugs and pharmacologically active molecules.
Scheme 73: Cu(I) DAPTA-catalyzed 1,2,3-triazole formation.
Scheme 74: Mechanism for Cu(I) DAPTA-catalyzed triazole formation.
Scheme 75: Synthesis of β-hydroxy-1,2,3-triazole.
Scheme 76: Proposed mechanism for synthesis of β-hydroxy-1,2,3-triazoles.
Scheme 77: Synthesis of bis-1,2,4-triazoles.
Scheme 78: Proposed mechanism for bis-1,2,4-triazoles synthesis.
Figure 14: Thiazole containing drugs.
Scheme 79: Synthesis of a substituted thiazole ring.
Scheme 80: Synthesis of pyrazolothiazoles.
Figure 15: Chromene containing drugs.
Scheme 81: Magnetic nanocatalyst-mediated aminochromene synthesis.
Scheme 82: Proposed mechanism for the synthesis of chromenes.
Beilstein J. Org. Chem. 2021, 17, 719–729, doi:10.3762/bjoc.17.61
Graphical Abstract
Figure 1: Structures of dibenzosuberenone 1 and pyridazine and pyrrole derivatives.
Figure 2: Structures of s-tetrazines 2a–l.
Scheme 1: Inverse electron-demand Diels–Alder reactions of dibenzosuberenone (1) with tetrazines 2a–l.
Scheme 2: Inverse electron-demand Diels–Alder reactions between dibenzosuberenone 1 and tetrazines 2ka and 2lb...
Scheme 3: Proposed reaction mechanism for the formation of dibenzosuberenone derivatives 3 and 4.
Scheme 4: Proposed mechanism for the formation of 5l.
Scheme 5: Oxidation of dihydropyridazines 3a–f. All reactions were carried in CH2Cl2 at room temperature (4e:...
Scheme 6: Synthesis of pyrrole 10a. a1.34 mmol 4a, Zinc (for 10aa: 6.68 mmol, for 10ab: 13.36 mmol), 10 mL gl...
Scheme 7: Synthesis of pyrrole 10b. a1.21 mmol 4b, 12.10 mmol Zinc, 118 °C, 2 h. b1.13 mmol 10ba, 1.69 mmol K...
Scheme 8: Synthesis of p-quinone methides 13–16. a1.77 mmol 11, 1.77 mmol 2, 5 mL toluene, 80 °C (13a: overni...
Scheme 9: Proposed mechanism for the formation of 13.
Figure 3: UV–vis spectra of 3c–f and 3k in CH3CN at rt (c = 5 μM).
Figure 4: Fluorescence spectra of 3c–f and 3k in CH3CN at rt (c = 5 μM).
Figure 5: Ambient (top) and fluorescence (bottom, under 365 nm UV light) images of 3c–f and 3k in CH3CN.
Beilstein J. Org. Chem. 2021, 17, 245–272, doi:10.3762/bjoc.17.25
Graphical Abstract
Scheme 1: Synthesis of 1,1-difluoro-2,3-dimethylcyclopropane (2).
Scheme 2: Cyclopropanation via dehydrohalogenation of chlorodifluoromethane.
Scheme 3: Difluorocyclopropanation of methylstyrene 7 using dibromodifluoromethane and zinc.
Scheme 4: Synthesis of difluorocyclopropanes from the reaction of dibromodifluoromethane and triphenylphosphi...
Scheme 5: Generation of difluorocarbene in a catalytic two-phase system and its addition to tetramethylethyle...
Scheme 6: The reaction of methylstyrene 7 with chlorodifluoromethane (11) in the presence of a tetraarylarson...
Scheme 7: Pyrolysis of sodium chlorodifluoroacetate (12) in refluxing diglyme in the presence of alkene 13.
Scheme 8: Synthesis of boron-substituted gem-difluorocyclopropanes 16.
Scheme 9: Addition of sodium bromodifluoroacetate (17) to alkenes.
Scheme 10: Addition of sodium bromodifluoroacetate (17) to silyloxy-substituted cyclopropanes 20.
Scheme 11: Synthesis of difluorinated nucleosides.
Scheme 12: Addition of butyl acrylate (26) to difluorocarbene generated from TFDA (25).
Scheme 13: Addition of difluorocarbene to propargyl esters 27 and conversion of the difluorocyclopropenes 28 t...
Scheme 14: The generation of difluorocyclopropanes using MDFA 30.
Scheme 15: gem-Difluorocyclopropanation of styrene (32) using difluorocarbene generated from TMSCF3 (31) under...
Scheme 16: Synthesis of a gem-difluorocyclopropane derivative using HFPO (41) as a source of difluorocarbene.
Scheme 17: Cyclopropanation of (Z)-2-butene in the presence of difluorodiazirine (44).
Scheme 18: The cyclopropanation of 1-octene (46) using Seyferth's reagent (45) as a source of difluorocarbene.
Scheme 19: Alternative approaches for the difluorocarbene synthesis from trimethyl(trifluoromethyl)tin (48).
Scheme 20: Difluorocyclopropanation of cyclohexene (49).
Scheme 21: Synthesis of difluorocyclopropane derivative 53 using bis(trifluoromethyl)cadmium (51) as the diflu...
Scheme 22: Addition of difluorocarbene generated from tris(trifluoromethyl)bismuth (54).
Scheme 23: Addition of a stable (trifluoromethyl)zinc reagent to styrenes.
Scheme 24: The preparation of 2,2-difluorocyclopropanecarboxylic acids of type 58.
Scheme 25: Difluorocyclopropanation via Michael cyclization.
Scheme 26: Difluorocyclopropanation using N-acylimidazolidinone 60.
Scheme 27: Difluorocyclopropanation through the cyclization of phenylacetonitrile (61) and 1,2-dibromo-1,1-dif...
Scheme 28: gem-Difluoroolefins 64 for the synthesis of functionalized cyclopropanes 65.
Scheme 29: Preparation of aminocyclopropanes 70.
Scheme 30: Synthesis of fluorinated methylenecyclopropane 74 via selenoxide elimination.
Scheme 31: Reductive dehalogenation of (1R,3R)-75.
Scheme 32: Synthesis of chiral monoacetates by lipase catalysis.
Scheme 33: Transformation of (±)-trans-81 using Rhodococcus sp. AJ270.
Scheme 34: Transformation of (±)-trans-83 using Rhodococcus sp. AJ270.
Scheme 35: Hydrogenation of difluorocyclopropenes through enantioselective hydrocupration.
Scheme 36: Enantioselective transfer hydrogenation of difluorocyclopropenes with a Ru-based catalyst.
Scheme 37: The thermal transformation of trans-1,2-dichloro-3,3-difluorocyclopropane (84).
Scheme 38: cis–trans-Epimerization of 1,1-difluoro-2,3-dimethylcyclopropane.
Scheme 39: 2,2-Difluorotrimethylene diradical intermediate.
Scheme 40: Ring opening of stereoisomers 88 and 89.
Scheme 41: [1,3]-Rearrangement of alkenylcyclopropanes 90–92.
Scheme 42: Thermolytic rearrangement of 2,2-difluoro-1-vinylcyclopropane (90).
Scheme 43: Thermal rearrangement for ethyl 3-(2,2-difluoro)-3-phenylcyclopropyl)acrylates 93 and 95.
Scheme 44: Possible pathways of the ring opening of 1,1-difluoro-2-vinylcyclopropane.
Scheme 45: Equilibrium between 1,1-difluoro-2-methylenecyclopropane (96) and (difluoromethylene)cyclopropane 97...
Scheme 46: Ring opening of substituted 1,1-difluoro-2,2-dimethyl-3-methylenecyclopropane 98.
Scheme 47: 1,1-Difluorospiropentane rearrangement.
Scheme 48: Acetolysis of (2,2-difluorocyclopropyl)methyl tosylate (104) and (1,1-difluoro-2-methylcyclopropyl)...
Scheme 49: Ring opening of gem-difluorocyclopropyl ketones 106 and 108 by thiolate nucleophiles.
Scheme 50: Hydrolysis of gem-difluorocyclopropyl acetals 110.
Scheme 51: Ring-opening reaction of 2,2-difluorocyclopropyl ketones 113 in the presence of ionic liquid as a s...
Scheme 52: Ring opening of gem-difluorocyclopropyl ketones 113a by MgI2-initiated reaction with diarylimines 1...
Scheme 53: Ring-opening reaction of gem-difluorocyclopropylstannanes 117.
Scheme 54: Preparation of 1-fluorovinyl vinyl ketone 123 and the synthesis of 2-fluorocyclopentenone 124. TBAT...
Scheme 55: Iodine atom-transfer ring opening of 1,1-difluoro-2-(1-iodoalkyl)cyclopropanes 125a–c.
Scheme 56: Ring opening of bromomethyl gem-difluorocyclopropanes 130 and formation of gem-difluoromethylene-co...
Scheme 57: Ring-opening aerobic oxidation reaction of gem-difluorocyclopropanes 132.
Scheme 58: Dibrominative ring-opening functionalization of gem-difluorocyclopropanes 134.
Scheme 59: The selective formation of (E,E)- and (E,Z)-fluorodienals 136 and 137 from difluorocyclopropyl acet...
Scheme 60: Proposed mechanism for the reaction of difluoro(methylene)cyclopropane 139 with Br2.
Scheme 61: Thermal rearrangement of F2MCP 139 and iodine by CuI catalysis.
Scheme 62: Synthesis of 2-fluoropyrroles 142.
Scheme 63: Ring opening of gem-difluorocyclopropyl ketones 143 mediated by BX3.
Scheme 64: Lewis acid-promoted ring-opening reaction of 2,2-difluorocyclopropanecarbonyl chloride (148).
Scheme 65: Ring-opening reaction of the gem-difluorocyclopropyl ketone 106 by methanolic KOH.
Scheme 66: Hydrogenolysis of 1,1-difluoro-3-methyl-2-phenylcyclopropane (151).
Scheme 67: Synthesis of monofluoroalkenes 157.
Scheme 68: The stereoselective Ag-catalyzed defluorinative ring-opening diarylation of 1-trimethylsiloxy-2,2-d...
Scheme 69: Synthesis of 2-fluorinated allylic compounds 162.
Scheme 70: Pd-catalyzed cross-coupling reactions of gem-difluorinated cyclopropanes 161.
Scheme 71: The (Z)-selective Pd-catalyzed ring-opening sulfonylation of 2-(2,2-difluorocyclopropyl)naphthalene...
Figure 1: Structures of zosuquidar hydrochloride and PF-06700841.
Scheme 72: Synthesis of methylene-gem-difluorocyclopropane analogs of nucleosides.
Figure 2: Anthracene-difluorocyclopropane hybrid derivatives.
Figure 3: Further examples of difluorcyclopropanes in modern drug discovery.