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Search for "iodonium" in Full Text gives 89 result(s) in Beilstein Journal of Organic Chemistry.
Synthesis of five- and six-membered cyclic organic peroxides: Key transformations into peroxide ring-retaining products
- Alexander O. Terent'ev,
- Dmitry A. Borisov,
- Vera A. Vil’ and
- Valery M. Dembitsky
Beilstein J. Org. Chem. 2014, 10, 34–114, doi:10.3762/bjoc.10.6
- hydroperoxide group. The treatment of unsaturated monoperoxyketals 257, 260, and 263 (prepared by ozonolysis of 256, 259, and 262 in methanol, respectively) with such donors of halonium ions such as N-iodosuccinimide (NIS), I2/t-BuOK, or bis(sym-collidine)iodonium hexafluorophosphate gave iodine-containing 1,2
- hydroperoxyalkenes 265a–c, 267, and 269a,b with bis(sym-collidine)iodonium hexaflulorophosphate (BCIH) in the cyclization step (Scheme 74). 3.9. Pd(II)-catalyzed cyclization The palladium-catalyzed cyclization of δ-unsaturated hydroperoxides 271 represents a new route to 1,2-dioxane cyclic compounds 272 (Scheme 75
Graphical Abstract
Figure 1: Five and six-membered cyclic peroxides.
Figure 2: Artemisinin and semi-synthetic derivatives.
Scheme 1: Synthesis of 3-hydroxy-1,2-dioxolanes 3a–c.
Scheme 2: Synthesis of dioxolane 6.
Scheme 3: Photooxygenation of oxazolidines 7a–d with formation of spiro-fused oxazolidine-containing dioxolan...
Scheme 4: Oxidation of cyclopropanes 10a–e and 11a–e with preparation of 1,2-dioxolanes 12a–e.
Scheme 5: VO(acac)2-catalyzed oxidation of silylated bicycloalkanols 13a–c.
Scheme 6: Mn(II)-catalyzed oxidation of cyclopropanols 15a–g.
Scheme 7: Oxidation of aminocyclopropanes 20a–c.
Scheme 8: Synthesis of aminodioxolanes 24.
Figure 3: Trifluoromethyl-containing dioxolane 25.
Scheme 9: Synthesis of 1,2-dioxolanes 27a–e by the oxidation of cyclopropanes 26a–e.
Scheme 10: Photoinduced oxidation of methylenecyclopropanes 28.
Scheme 11: Irradiation-mediated oxidation.
Scheme 12: Application of diazene 34 for dioxolane synthesis.
Scheme 13: Mn(OAc)3-catalyzed cooxidation of arylacetylenes 37a–h and acetylacetone with atmospheric oxygen.
Scheme 14: Peroxidation of (2-vinylcyclopropyl)benzene (40).
Scheme 15: Peroxidation of 1,4-dienes 43a,b.
Scheme 16: Peroxidation of 1,5-dienes 46.
Scheme 17: Peroxidation of oxetanes 53a,b.
Scheme 18: Peroxidation of 1,6-diene 56.
Scheme 19: Synthesis of 3-alkoxy-1,2-dioxolanes 62a,b.
Scheme 20: Synthesis of spiro-bis(1,2-dioxolane) 66.
Scheme 21: Synthesis of dispiro-1,2-dioxolanes 68, 70, 71.
Scheme 22: Synthesis of spirohydroperoxydioxolanes 75a,b.
Scheme 23: Synthesis of spirohydroperoxydioxolane 77 and dihydroperoxydioxolane 79.
Scheme 24: Ozonolysis of azepino[4,5-b]indole 80.
Scheme 25: SnCl4-mediated fragmentation of ozonides 84a–l in the presence of allyltrimethylsilane.
Scheme 26: SnCl4-mediated fragmentation of bicyclic ozonide 84m in the presence of allyltrimethylsilane.
Scheme 27: MCl4-mediated fragmentation of alkoxyhydroperoxides 96 in the presence of allyltrimethylsilane.
Scheme 28: SnCl4-catalyzed reaction of monotriethylsilylperoxyacetal 108 with alkene 109.
Scheme 29: SnCl4-catalyzed reaction of triethylsilylperoxyacetals 111 with alkenes.
Scheme 30: Desilylation of tert-butyldimethylsilylperoxy ketones 131a,b followed by cyclization.
Scheme 31: Deprotection of peroxide 133 followed by cyclization.
Scheme 32: Asymmetric peroxidation of methyl vinyl ketones 137a–e.
Scheme 33: Et2NH-catalyzed intramolecular cyclization.
Scheme 34: Synthesis of oxodioxolanes 143a–j.
Scheme 35: Haloperoxidation accompanied by intramolecular ring closure.
Scheme 36: Oxidation of triterpenes 149a–d with Na2Cr2O7/N-hydroxysuccinimide.
Scheme 37: Curtius and Wolff rearrangements to form 1,2-dioxolane ring-retaining products.
Scheme 38: Oxidative desilylation of peroxide 124.
Scheme 39: Synthesis of dioxolane 158, a compound containing the aminoquinoline antimalarial pharmacophore.
Scheme 40: Diastereomers of plakinic acid A, 162a and 162b.
Scheme 41: Ozonolysis of alkenes.
Scheme 42: Cross-ozonolysis of alkenes 166 with carbonyl compounds.
Scheme 43: Ozonolysis of the bicyclic cyclohexenone 168.
Scheme 44: Cross-ozonolysis of enol ethers 172a,b with cyclohexanone.
Scheme 45: Griesbaum co-ozonolysis.
Scheme 46: Reactions of aryloxiranes 177a,b with oxygen.
Scheme 47: Intramolecular formation of 1,2,4-trioxolane 180.
Scheme 48: Formation of 1,2,4-trioxolane 180 by the reaction of 1,5-ketoacetal 181 with H2O2.
Scheme 49: 1,2,4-Trioxolane 186 with tetrazole fragment.
Scheme 50: 1,2,4-Trioxolane 188 with a pyridine fragment.
Scheme 51: 1,2,4-Trioxolane 189 with pyrimidine fragment.
Scheme 52: Synthesis of aminoquinoline-containing 1,2,4-trioxalane 191.
Scheme 53: Synthesis of arterolane.
Scheme 54: Oxidation of diarylheptadienes 197a–c with singlet oxygen.
Scheme 55: Synthesis of hexacyclinol peroxide 200.
Scheme 56: Oxidation of enone 201 and enenitrile 203 with singlet oxygen.
Scheme 57: Synthesis of 1,2-dioxanes 207 by oxidative coupling of carbonyl compounds 206 and alkenes 205.
Scheme 58: 1,2-Dioxanes 209 synthesis by co-oxidation of 1,5-dienes 208 and thiols.
Scheme 59: Synthesis of bicyclic 1,2-dioxanes 212 with aryl substituents.
Scheme 60: Isayama–Mukaiyama peroxysilylation of 1,5-dienes 213 followed by desilylation under acidic conditio...
Scheme 61: Synthesis of bicycle 218 with an 1,2-dioxane ring.
Scheme 62: Intramolecular cyclization with an oxirane-ring opening.
Scheme 63: Inramolecular cyclization with the oxetane-ring opening.
Scheme 64: Intramolecular cyclization with the attack on a keto group.
Scheme 65: Peroxidation of the carbonyl group in unsaturated ketones 228 followed by cyclization of hydroperox...
Scheme 66: CsOH and Et2NH-catalyzed cyclization.
Scheme 67: Preparation of peroxyplakoric acid methyl ethers A and D.
Scheme 68: Hg(OAc)2 in 1,2-dioxane synthesis.
Scheme 69: Reaction of 1,4-diketones 242 with hydrogen peroxide.
Scheme 70: Inramolecular cyclization with oxetane-ring opening.
Scheme 71: Inramolecular cyclization with MsO fragment substitution.
Scheme 72: Synthesis of 1,2-dioxane 255a, a structurally similar compound to natural peroxyplakoric acids.
Scheme 73: Synthesis of 1,2-dioxanes based on the intramolecular cyclization of hydroperoxides containing C=C ...
Scheme 74: Use of BCIH in the intramolecular cyclization.
Scheme 75: Palladium-catalyzed cyclization of δ-unsaturated hydroperoxides 271a–e.
Scheme 76: Intramolecular cyclization of unsaturated peroxyacetals 273a–d.
Scheme 77: Allyltrimethylsilane in the synthesis of 1,2-dioxanes 276a–d.
Scheme 78: Intramolecular cyclization using the electrophilic center of the peroxycarbenium ion 279.
Scheme 79: Synthesis of bicyclic 1,2-dioxanes.
Scheme 80: Preparation of 1,2-dioxane 286.
Scheme 81: Di(tert-butyl)peroxalate-initiated radical cyclization of unsaturated hydroperoxide 287.
Scheme 82: Oxidation of 1,4-betaines 291a–d.
Scheme 83: Synthesis of aminoquinoline-containing 1,2-dioxane 294.
Scheme 84: Synthesis of the sulfonyl-containing 1,2-dioxane.
Scheme 85: Synthesis of the amido-containing 1,2-dioxane 301.
Scheme 86: Reaction of singlet oxygen with the 1,3-diene system 302.
Scheme 87: Synthesis of (+)-premnalane А and 8-epi-premnalane A.
Scheme 88: Synthesis of the diazo group containing 1,2-dioxenes 309a–e.
Figure 4: Plakortolide Е.
Scheme 89: Synthesis of 6-epiplakortolide Е.
Scheme 90: Application of Bu3SnH for the preparation of tetrahydrofuran-containing bicyclic peroxides 318a,b.
Scheme 91: Application of Bu3SnH for the preparation of lactone-containing bicyclic peroxides 320a–f.
Scheme 92: Dihydroxylation of the double bond in the 1,2-dioxene ring 321 with OsO4.
Scheme 93: Epoxidation of 1,2-dioxenes 324.
Scheme 94: Cyclopropanation of the double bond in endoperoxides 327.
Scheme 95: Preparation of pyridazine-containing bicyclic endoperoxides 334a–c.
Scheme 96: Synthesis of 1,2,4-trioxanes 337 by the hydroperoxidation of unsaturated alcohols 335 with 1O2 and ...
Scheme 97: Synthesis of sulfur-containing 1,2,4-trioxanes 339.
Scheme 98: BF3·Et2O-catalyzed synthesis of the 1,2,4-trioxanes 342a–g.
Scheme 99: Photooxidation of enol ethers or vinyl sulfides 343.
Scheme 100: Synthesis of tricyclic peroxide 346.
Scheme 101: Reaction of endoperoxides 348a,b derived from cyclohexadienes 347a,b with 1,4-cyclohexanedione.
Scheme 102: [4 + 2]-Cycloaddition of singlet oxygen to 2Н-pyrans 350.
Scheme 103: Synthesis of 1,2,4-trioxanes 354 using peroxysilylation stage.
Scheme 104: Epoxide-ring opening in 355 with H2O2 followed by the condensation of hydroxy hydroperoxides 356 wi...
Scheme 105: Peroxidation of unsaturated ketones 358 with the H2O2/CF3COOH/H2SO4 system.
Scheme 106: Synthesis of 1,2,4-trioxanes 362 through Et2NH-catalyzed intramolecular cyclization.
Scheme 107: Reduction of the double bond in tricyclic peroxides 363.
Scheme 108: Horner–Wadsworth–Emmons reaction in the presence of peroxide group.
Scheme 109: Reduction of ester group by LiBH4 in the presence of 1,2,4-trioxane moiety.
Scheme 110: Reductive amination of keto-containing 1,2,4-trioxane 370.
Scheme 111: Reductive amination of keto-containing 1,2,4-trioxane and a Fe-containing moiety.
Scheme 112: Acid-catalyzed reactions of Н2О2 with ketones and aldehydes 374.
Scheme 113: Cyclocondensation of carbonyl compounds 376a–d using Me3SiOOSiMe3/CF3SO3SiMe3.
Scheme 114: Peroxidation of 4-methylcyclohexanone (378).
Scheme 115: Synthesis of symmetrical tetraoxanes 382a,b from aldehydes 381a,b.
Scheme 116: Synthesis of unsymmetrical tetraoxanes using of MeReO3.
Scheme 117: Synthesis of symmetrical tetraoxanes using of MeReO3.
Scheme 118: Synthesis of symmetrical tetraoxanes using of MeReO3.
Scheme 119: MeReO3 in the synthesis of symmetrical tetraoxanes with the use of aldehydes.
Scheme 120: Preparation of unsymmmetrical 1,2,4,5-tetraoxanes with high antimalarial activity.
Scheme 121: Re2O7-Catalyzed synthesis of tetraoxanes 398.
Scheme 122: H2SO4-Catalyzed synthesis of steroidal tetraoxanes 401.
Scheme 123: HBF4-Catalyzed condensation of bishydroperoxide 402 with 1,4-cyclohexanedione.
Scheme 124: BF3·Et2O-Catalyzed reaction of gem-bishydroperoxides 404 with enol ethers 405 and acetals 406.
Scheme 125: HBF4-Catalyzed cyclocondensation of bishydroperoxide 410 with ketones.
Scheme 126: Synthesis of symmetrical and unsymmetrical tetraoxanes 413 from benzaldehydes 412.
Scheme 127: Synthesis of bridged 1,2,4,5-tetraoxanes 415a–l from β-diketones 414a–l and H2O2.
Scheme 128: Dimerization of zwitterions 417.
Scheme 129: Ozonolysis of verbenone 419.
Scheme 130: Ozonolysis of O-methyl oxime 424.
Scheme 131: Peroxidation of 1,1,1-trifluorododecan-2-one 426 with oxone.
Scheme 132: Intramolecular cyclization of dialdehyde 428 with H2O2.
Scheme 133: Tetraoxanes 433–435 as by-products in peroxidation of ketals 430–432.
Scheme 134: Transformation of triperoxide 436 in diperoxide 437.
Scheme 135: Preparation and structural modifications of tetraoxanes.
Scheme 136: Structural modifications of steroidal tetraoxanes.
Scheme 137: Synthesis of 1,2,4,5-tetraoxane 454 containing the fluorescent moiety.
Scheme 138: Synthesis of tetraoxane 458 (RKA182).
Recent advances in transition metal-catalyzed Csp2-monofluoro-, difluoro-, perfluoromethylation and trifluoromethylthiolation
- Grégory Landelle,
- Armen Panossian,
- Sergiy Pazenok,
- Jean-Pierre Vors and
- Frédéric R. Leroux
Beilstein J. Org. Chem. 2013, 9, 2476–2536, doi:10.3762/bjoc.9.287
- bond cleavage of Togni's reagent in presence of the copper catalyst to produce a highly electrophilic species (intermediate A). Then, the acrylate derivative coordinates to the iodonium salt A leading to intermediate B with generation of hydrogen fluoride, followed by an intramolecular reaction between
- the double bond and the iodonium ion to provide intermediate C. The presence of HF in the reaction medium promotes the decarboxylation step in intermediate C, and subsequent reductive elimination leads to the formation of the thermodynamically stable E-alkene. Finally, protonation of intermediate E
Graphical Abstract
Scheme 1: Pd-catalyzed monofluoromethylation of pinacol phenylboronate [44].
Scheme 2: Cu-catalyzed monofluoromethylation with 2-PySO2CHFCOR followed by desulfonylation [49].
Scheme 3: Cu-catalyzed difluoromethylation with α-silyldifluoroacetates [57].
Figure 1: Mechanism of the Cu-catalyzed C–CHF2 bond formation of α,β-unsaturated carboxylic acids through dec...
Scheme 4: Fe-catalyzed decarboxylative difluoromethylation of cinnamic acids [62].
Scheme 5: Preliminary experiments for investigation of the mechanism of the C–H trifluoromethylation of N-ary...
Figure 2: Plausible catalytic cycle proposed by Z.-J. Shi et al. for the trifluoromethylation of acetanilides ...
Figure 3: Plausible catalytic cycle proposed by M. S. Sanford et al. for the perfluoroalkylation of simple ar...
Figure 4: Postulated reaction pathway for the Ag/Cu-catalyzed trifluoromethylation of aryl iodides by Z. Q. W...
Figure 5: Postulated reaction mechanism for Cu-catalyzed trifluoromethylation reaction using MTFA as trifluor...
Scheme 6: Formal Heck-type trifluoromethylation of vinyl(het)arenes by M. Sodeoka et al. [83].
Figure 6: Proposed catalytic cycle for the copper-catalyzed trifluoromethylation of (het)arenes in presence o...
Figure 7: Proposed catalytic cycle for the copper-catalyzed trifluoromethylation of N,N-disubstituted (hetero...
Figure 8: Proposed catalytic cycle by Y. Zhang and J. Wang et al. for the copper-catalyzed trifluoromethylati...
Figure 9: Mechanistic rationale for the trifluoromethylation of arenes in presence of Langlois’s reagent and ...
Scheme 7: Trifluoromethylation of 4-acetylpyridine with Langlois’s reagent by P. S. Baran et al. (* Stirring ...
Scheme 8: Catalytic copper-facilitated perfluorobutylation of benzene with C4F9I and benzoyl peroxide [90].
Figure 10: F.-L. Qing et al.’s proposed mechanism for the copper-catalyzed trifluoromethylation of (hetero)are...
Figure 11: Mechanism of the Cu-catalyzed/Ru-photocatalyzed trifluoromethylation and perfluoroalkylation of ary...
Figure 12: Proposed mechanism for the Cu-catalyzed trifluoromethylation of aryl- and vinyl boronic acids with ...
Figure 13: Possible mechanism for the Cu-catalyzed decarboxylative trifluoromethylation of cinnamic acids [62].
Scheme 9: Ruthenium-catalyzed perfluoroalkylation of alkenes and (hetero)arenes with perfluoroalkylsulfonyl c...
Figure 14: N. Kamigata et al.’s proposed mechanism for the Ru-catalyzed perfluoroalkylation of alkenes and (he...
Figure 15: Proposed mechanism for the Ru-catalyzed photoredox trifluoromethylation of (hetero)arenes with trif...
Figure 16: Late-stage trifluoromethylation of pharmaceutically relevant molecules with trifluoromethanesulfony...
Figure 17: Proposed mechanism for the trifluoromethylation of alkenes with trifluoromethyl iodide under Ru-bas...
Scheme 10: Formal perfluoroakylation of terminal alkenes by Ru-catalyzed cross-metathesis with perfluoroalkyle...
Figure 18: One-pot Ir-catalyzed borylation/Cu-catalyzed trifluoromethylation of complex small molecules by Q. ...
Figure 19: Mechanistic proposal for the Ni-catalyzed perfluoroalkylation of arenes and heteroarenes with perfl...
Scheme 11: Electrochemical Ni-catalyzed perfluoroalkylation of 2-phenylpyridine (Y. H. Budnikova et al.) [71].
Scheme 12: Fe(II)-catalyzed trifluoromethylation of arenes and heteroarenes with trifluoromethyl iodide (T. Ya...
Figure 20: Mechanistic proposal by T. Yamakawa et al. for the Fe(II)-catalyzed trifluoromethylation of arenes ...
Scheme 13: Ytterbium-catalyzed perfluoroalkylation of dihydropyran with perfluoroalkyl iodide (Y. Ding et al.) ...
Figure 21: Mechanistic proposal by A. Togni et al. for the rhenium-catalyzed trifluoromethylation of arenes an...
Figure 22: Mechanism of the Cu-catalyzed oxidative trifluoromethylthiolation of arylboronic acids with TMSCF3 ...
Scheme 14: Removal of the 8-aminoquinoline auxiliary [136].
Figure 23: Mechanism of the Cu-catalyzed trifluoromethylthiolation of C–H bonds with a trifluoromethanesulfony...
Straightforward synthesis of a tetrasaccharide repeating unit corresponding to the O-antigen of Escherichia coli O16
- Manas Jana and
- Anup Kumar Misra
Beilstein J. Org. Chem. 2013, 9, 1757–1762, doi:10.3762/bjoc.9.203
- iodonium ion mediated glycosylation conditions; (c) the use of p-methoxybenzyl (PMB) ether protection as an in situ removable protecting group in a one-pot glycosylation reaction and its removal [17] and (d) the use of galactofuranosidic thioglycoside as a glycosyl donor. The iodonium ion promoted
Graphical Abstract
Figure 1: Structure of the tetrasaccharide repeating unit of the O-antigen of Escherichia coli O16.
Figure 2: Structure of the synthesized pentasaccharide and its synthetic intermediates.
Scheme 1: Reagents: (a) N-iodosuccinimide (NIS), TfOH, CH2Cl2, MS 4 Å, −30 °C, 1 h, then 0 °C, 1 h, 76%; (b) ...
Palladium-catalyzed synthesis of N-arylated carbazoles using anilines and cyclic diaryliodonium salts
- Stefan Riedmüller and
- Boris J. Nachtsheim
Beilstein J. Org. Chem. 2013, 9, 1202–1209, doi:10.3762/bjoc.9.136
- The direct synthesis of N-arylated carbazoles through a palladium-catalyzed amination of cyclic iodonium salts with anilines is described. In particular, electron-poor aniline derivatives reacted smoothly with only 5 mol % of Pd(OAc)2 as catalyst to give the desired products in up to 71% yield
- . Furthermore, the reactivity of cyclic iodonium salts is compared with the reactivity of the corresponding cyclic bromonium analogues. Keywords: amination; carbazoles; hypervalent; iodine; iodonium salts; Introduction Carbazoles play an important role as core structural elements in natural products (e.g
- ] or the direct arylation [14][15] of the free NH-functionality of carbazole (path B). In the past decade, hypervalent iodine chemistry has undergone a renaissance and has developed to become a powerful area in synthetic organic chemistry. Open-chained iodonium salts are well explored in transition
Graphical Abstract
Figure 1: Representative examples of carbazoles with hole-transport, host or luminescent properties.
Scheme 1: Synthetic access to N-arylated carbazoles.
Scheme 2: Proposed mechanistic motivation towards the formation of 3a.
Figure 2: FID chromatogram of the reaction mixture. Only the most intense peaks were structurally assigned. x...
Figure 3: Substrate scope. All reactions were performed using iodonium salt 1 (0.35 mmol), 1.2 equiv of prima...
Scheme 3: Synthesis of dibenzo[b,d]bromolium trifluoromethanesulfonate (6).
Scheme 4: Dibenzo[b,d]bromolium trifluoromethanesulfonate (6) and p-fluoroaniline (2f) to construct carbazole ...
New core-pyrene π structure organophotocatalysts usable as highly efficient photoinitiators
- Sofia Telitel,
- Frédéric Dumur,
- Thomas Faury,
- Bernadette Graff,
- Mohamad-Ali Tehfe,
- Didier Gigmes,
- Jean-Pierre Fouassier and
- Jacques Lalevée
Beilstein J. Org. Chem. 2013, 9, 877–890, doi:10.3762/bjoc.9.101
- application of two- and three-component photoinitiating systems (different Co_Pys with the addition of iodonium or sulfonium salts, alkyl halide or amine) was investigated in detail for cationic and radical photopolymerization reactions under near-UV–vis light. The proposed compounds can behave as new
- polymerization (ROP) under exposure to the near-UV–vis light delivered by a Hg–Xe lamp (~30 mW cm−2) and the visible light of a halogen lamp (soft irradiation conditions; ~10 mW cm−2) is investigated. The Co_Pys are used in combination with additives: iodonium or sulfonium salts for ROP and amine or/and alkyl
- Co_Py/phenacyl bromide PBr (or the iodonium salt, Iod) interaction is very favorable (ΔG << 0). Py_2 exhibits the most favorable ΔGs: −2.45 eV (Iod) and −1.87 eV (PBr). MO calculations show that the calculated and experimental values (Table 1) are approximately the same, e.g., a difference of 5 to 10 nm
Graphical Abstract
Scheme 1: Typical reactions for photoinitiated cationic polymerization.
Scheme 2: Examples of previously investigated architectures.
Scheme 3: Investigated Co_Pys.
Scheme 4: Other chemical compounds.
Figure 1: UV–vis absorption spectra of the investigated compounds: (A) In acetonitrile for Py_1 and acetonitr...
Figure 2: HOMO–LUMO orbitals for Py_2, Py_3, Py_5, Py_6, Py_8, Py_11 and Py_12 involved in the π–π* transitio...
Figure 3: Fluorescence quenching of 1Py_3 by the phenacylbromide (PBr) in acetonitrile/toluene (50/50). Inser...
Scheme 5: Photochemical processes for the different Co_Pys.
Figure 4: ESR spectra obtained upon irradiation of (A) Py_3/Iod, (B) Py_3/PBr and (C) Py_3/EDB in tert-butylb...
Figure 5: ESR-spin trapping spectra of Py_9/Iod in tert-butylbenzene (storage at rt for 24 h); (a) experiment...
Figure 6: Photopolymerization profiles of EPOX upon Xe–Hg lamp irradiation (λ > 340 nm) under air for differe...
Figure 7: Photopolymerization profiles of EPOX upon a Xe–Hg lamp irradiation (λ > 340 nm) under air for diffe...
Figure 8: (A) Photopolymerization profiles of EPOX-Si upon a Xe–Hg lamp irradiation (λ > 340 nm) under air fo...
Figure 9: Photopolymerization profiles of TMPTA upon Xe–Hg lamp irradiation (λ > 340 nm) in laminate for diff...
Figure 10: Photolysis of (A) the Py_3/PBr couple, (B) the Py_3/Iod couple, and (C) the Py_3/MDEA couple; Xe–Hg...
Figure 11: Photolysis of (A) the Py_11/Iod and (B) the Py_11/Iod/NVK couple. Halogen lamp irradiation. In acet...
Scheme 6: The oxidative cycle.
Scheme 7: Oxidation versus reduction cycles.
Convergent synthesis of the tetrasaccharide repeating unit of the cell wall lipopolysaccharide of Escherichia coli O40
- Abhijit Sau and
- Anup Kumar Misra
Beilstein J. Org. Chem. 2012, 8, 2053–2059, doi:10.3762/bjoc.8.230
- glycosylation” concept [19][24] (Scheme 2). Iodonium ion promoted [2 + 2] stereoselective glycosylation of compound 8 and compound 9 in the presence of NIS and HClO4–SiO2 [17] furnished tetrasaccharide derivative 10 in 71% yield. Formation of compound 10 was confirmed by its spectral analysis [signals at δ
Graphical Abstract
Figure 1: Structure of the tetrasaccharide repeating unit of the cell-wall lipopolysaccharide of Escherichia ...
Figure 2: Structure of the synthesized tetrasaccharide 1 and its synthetic precursors.
Scheme 1: Synthesis of disaccharide derivative 8. Reagents and conditions: (a) benzyl bromide, NaOH, DMF, roo...
Scheme 2: Synthesis of disaccharide derivative 9. Reagents and conditions: (a) NIS, HClO4–SiO2, MS 4Å, CH2Cl2...
Scheme 3: Synthesis of target tetrasaccharide 1. Reagents and conditions: (a) NIS, HClO4–SiO2, CH2Cl2, −15 °C...
2-Allylphenyl glycosides as complementary building blocks for oligosaccharide and glycoconjugate synthesis
- Hemali D. Premathilake and
- Alexei V. Demchenko
Beilstein J. Org. Chem. 2012, 8, 597–605, doi:10.3762/bjoc.8.66
- of both aryl and pentenyl glycosides, they should offer a more versatile activation profile than either class of the leaving group. Our working hypothesis is that activation of the AP leaving group with I+ takes place by the formation of an epi-iodonium ion, which is then opened with the anomeric
- activated for chemical glycosylation under a variety of conditions including Lewis acid and iodonium ion mediated pathways. The two activation pathways were confirmed by a mechanistic study. We also demonstrated that the application of the AP moiety allows executing oligosaccharide assembly by an orthogonal
Graphical Abstract
Scheme 1: Orthogonal strategy introduced by Ogawa et al.
Scheme 2: Determination of the AP activation pathways.
Scheme 3: AP building blocks in oligosaccharide synthesis.
Multistep flow synthesis of vinyl azides and their use in the copper-catalyzed Huisgen-type cycloaddition under inductive-heating conditions
- Lukas Kupracz,
- Jan Hartwig,
- Jens Wegner,
- Sascha Ceylan and
- Andreas Kirschning
Beilstein J. Org. Chem. 2011, 7, 1441–1448, doi:10.3762/bjoc.7.168
- reactor at the given flow rates are between 1.5 h to 3.5 h. Mechanistically the good regioselectivity is based on the generation of the more stable carbenium ion after electrophilic attack of the iodonium species on the olefinic double bond. In cases of aliphatic alkenes without aryl substituents
Graphical Abstract
Scheme 1: Hassner's synthesis of vinyl azides and a stable, nonexplosive analogue 5 of iodine azide (1).
Scheme 2: Preparation of polymer-bound bisazido iodate(I) 5 and polymer-bound 1,8-diaza-[5.4.0]bicyclo-7-unde...
Scheme 3: Two-step protocol for the preparation of vinyl azides 4a–e and 4g–i under flow conditions.
Scheme 4: Regeneration of functionalized polymers 5 and 8.
Scheme 5: Preparation of triazoles 12a–l by using inductively heated copper turnings as a packed-bed material...
Convergent synthesis of the tetrasaccharide repeating unit of the O-antigen of Shigella boydii type 9
- Abhishek Santra and
- Anup Kumar Misra
Beilstein J. Org. Chem. 2011, 7, 1182–1188, doi:10.3762/bjoc.7.137
- thioethyl group acts as an orthogonal anomeric protecting group since it acts as a glycosyl acceptor in the case of compound 4 whereas compound 7 has been used as the glycosyl donor in the next step. Iodonium ion promoted stereoselective glycosylation of the disaccharide thioglycoside donor 7 with the
Graphical Abstract
Figure 1: Structure of the tetrasaccharide repeating unit of the O-antigen of Shigella boydii type 9.
Figure 2: Structure of the synthesized tetrasaccharide and its intermediates.
Scheme 1: Reagents: (a) acetic anhydride, sulfamic acid, 60 °C, 30 min, 91%; (b) Et3SiH, I2, 0–5 °C, 30 min, ...
Scheme 2: Reagents: (a) HClO4–SiO2, CH2Cl2, −15 °C, 1 h, 81%; (b) benzyl bromide, NaOH, n-Bu4NBr, THF, rt, 2 ...
Scheme 3: Reagents: (a) N-iodosuccinimide, HClO4–SiO2, −10 °C, 1 h, 82%; (b) 0.1 M CH3ONa, CH3OH, rt, 3 h; (c...
A practical microreactor for electrochemistry in flow
- Kevin Watts,
- William Gattrell and
- Thomas Wirth
Beilstein J. Org. Chem. 2011, 7, 1108–1114, doi:10.3762/bjoc.7.127
- syntheses as mild, non-toxic and highly selective reagents. Iodine(III) reagents with two carbon ligands are known as iodonium salts. These salts are attractive alternatives to oxidants and catalysts based on heavy metals, as they have similar properties to those of heavy metal complexes and can, therefore
- , be used in similar reaction pathways, and are beneficial for organic synthesis due to their low toxicity and cost [20]. Iodonium salts are currently being used in three main types of reactions, namely ligand exchange, reductive elimination and ligand coupling. This is due to their highly electron
- increase the selectivity of the coupling reaction [21]. The sulfuric acid acts both as a counter reaction to the oxidation at the anode, with proton reduction, and simultaneously provides a counter ion for the positively charged iodonium salt. It also acts as an electrolyte in the reaction described above
Graphical Abstract
Scheme 1: Electrochemically generated N-acyliminium ions 1 and subsequent reactions.
Figure 1: Electrochemical microreactor.
Scheme 2: Electrolysis of furan.
Scheme 3: Kolbe electrolysis of phenylacetic acids 6 in flow.
Scheme 4: Synthesis of diaryliodonium salts 11 in flow.
When gold can do what iodine cannot do: A critical comparison
- Sara Hummel and
- Stefan F. Kirsch
Beilstein J. Org. Chem. 2011, 7, 847–859, doi:10.3762/bjoc.7.97
- domino processes, for which gold pre-catalysts were found to be outstandingly effective, were paralleled by employing iodine electrophiles in place of gold compounds. This review highlights how, in certain cases, iodonium activation can match gold-catalyzed reactions to construct identical product
- scaffolds. Likewise, processes are discussed where mostly identical starting materials are transformed into diverse frameworks depending on whether gold or iodonium activation was used to trigger the reaction. Keywords: catalysis; cycloisomerizations; domino reactions; gold; iodine; Introduction Over the
- reactions [41][42]. As a logical extension, one might speculate about analogous processes triggered by direct iodonium activation in the absence of gold catalysts (Scheme 1c). Since Barluenga, Larock, and others have shown over the last decades that various cyclizations of carbon and heteroatom nucleophiles
Graphical Abstract
Scheme 1: Mechanistic scenarios for alkyne activation.
Scheme 2: Synthesis of 3(2H)-furanones.
Scheme 3: Synthesis of furans.
Scheme 4: Formation of dihydrooxazoles.
Scheme 5: Variation on indole formation.
Scheme 6: Formation of naphthalenes.
Scheme 7: Formation of indenes.
Scheme 8: Iodocyclization of 3-silyloxy-1,5-enynes.
Scheme 9: 5-Endo cyclizations with concomitant nucleophilic trapping.
Scheme 10: Reactivity of 3-BocO-1,5-enynes.
Scheme 11: Intramolecular nucleophilic trapping.
Scheme 12: Approach to azaanthraquinones.
Scheme 13: Carbocyclizations with enol derivatives.
Scheme 14: Gold-catalyzed cyclization modes for 1,5-enynes.
Scheme 15: Iodine-induced cyclization of 1,5-enynes.
Scheme 16: Diverse reactivity of 1,6-enynes.
Scheme 17: Iodocyclization of 1,6-enynes.
Scheme 18: Cyclopropanation of alkenes with 1,6-enynes.
Scheme 19: Cyclopropanation of alkenes with 1,6-enynes.
Palladium- and copper-mediated N-aryl bond formation reactions for the synthesis of biological active compounds
- Carolin Fischer and
- Burkhard Koenig
Beilstein J. Org. Chem. 2011, 7, 59–74, doi:10.3762/bjoc.7.10
- resulted in good yields [4][26]. Copper-diamine-catalysed N-arylation facilitated the arylation of pyrroles, pyrazoles, indazoles, imidazoles, triazoles, benzimidazoles and indoles [27][28][29]. Besides aryl halides as the aryl donor, arylsiloxanes [30], arylstannanes [31], iodonium salts [32], aryl lead
Graphical Abstract
Scheme 1: Synthesis of selective D3 receptor ligands.
Scheme 2: Synthesis of a novel 5-HT1B receptor antagonist.
Scheme 3: Synthesis of A-366833, a selective α4β2 neural nicotinic receptor agonist.
Scheme 4: A new route to oxcarbazepine.
Scheme 5: Synthesis of key intermediates for norepinephrine transporter (NET) inhibitors.
Scheme 6: N-Annulation yielding substituted indole for the synthesis of demethylasterriquinone A1.
Scheme 7: Palladium-catalysed double N-arylation contributing to the synthesis of murrazoline.
Scheme 8: Synthesis of vitamin E amines.
Scheme 9: Improved synthesis of martinellic acid.
Scheme 10: New tariquidar-derived ABCB1 inhibitors.
Scheme 11: β-Carbolin-1-ones as inhibitors of tumour cell proliferation.
Scheme 12: Copper-catalysed synthesis of promazine drugs.
Scheme 13: Palladium-catalysed multicomponent reaction for the synthesis of promazine drugs.
Scheme 14: Key intermediate for imatinib.
Scheme 15: Synthesis of an effective Chek1/KDR kinase inhibitor.
Scheme 16: Macrocyclization as final step of the synthesis of heat shock protein inhibitor.
Scheme 17: Synthesis of N-arylimidazoles.
Scheme 18: Synthesis of benzolactam V8.
Scheme 19: Synthesis of an intermediate for lotrafiban (SB-214857).
Scheme 20: Intermolecular effort towards lotrafiban.
Scheme 21: Synthesis of matrix metalloproteases (MMPs) inhibitor.
Scheme 22: Regioselective 9-N-arylation of purines.
Scheme 23: N-Arylation of adenine and cytosine.
Scheme 24: 9-N-Arylpurines as enterovirus inhibitors.
Scheme 25: Xanthine analogues as kinase inhibitors.
Scheme 26: Synthesis of dual PPARα/γ agonists.
Scheme 27: N-Aryltriazole ribonucleosides with anti-proliferative activity.
Aromatic and heterocyclic perfluoroalkyl sulfides. Methods of preparation
- Vladimir N. Boiko
Beilstein J. Org. Chem. 2010, 6, 880–921, doi:10.3762/bjoc.6.88
Graphical Abstract
Figure 1: Examples of industrial fluorine-containing bio-active molecules.
Figure 2: CF3(S)- and CF3(O)-containing pharmacologically active compounds.
Figure 3: Hypotensive candidates with SRF and SO2RF groups – analogues of Losartan and Nifedipin.
Figure 4: The variety of the pharmacological activity of RFS-substituted compounds.
Figure 5: Recent examples of compounds containing RFS(O)n-groups [12-18].
Scheme 1: Fluorination of ArSCCl3 to corresponding ArSCF3 derivatives. For references see: a[38-43]; b[41,42]; c[43]; d[44]; e[38-43,45-47]; f[38-43,48,49]; g...
Scheme 2: Preparation of aryl pentafluoroethyl sulfides.
Scheme 3: Mild fluorination of the aryl SCF2Br derivatives.
Scheme 4: HF fluorinations of aryl α,α,β-trichloroisobutyl sulfide at various conditions.
Scheme 5: Monofluorination of α,α-dichloromethylene group.
Scheme 6: Electrophilic substitution of phenols with CF3SCl [69].
Scheme 7: Introduction of SCF3 groups into activated phenols [71-74].
Scheme 8: Preparation of tetrakis(SCF3)-4-methoxyphenol [72].
Scheme 9: The interactions of resorcinol and phloroglucinol derivatives with RFSCl.
Scheme 10: Reactions of anilines with CF3SCl.
Scheme 11: Trifluoromethylsulfanylation of anilines with electron-donating groups in the meta position [74].
Scheme 12: Reaction of benzene with CF3SCl/CF3SO3H [77].
Scheme 13: Reactions of trifluoromethyl sulfenyl chloride with aryl magnesium and -mercury substrates.
Scheme 14: Reactions of pyrroles with CF3SCl.
Scheme 15: Trifluoromethylsulfanylation of indole and indolizines.
Scheme 16: Reactions of N-methylpyrrole with CF3SCl [80,82].
Scheme 17: Reactions of furan, thiophene and selenophene with CF3SCl.
Scheme 18: Trifluoromethylsulfanylation of imidazole and thiazole derivatives [83].
Scheme 19: Trifluoromethylsulfanylation of pyridine requires initial hydride reduction.
Scheme 20: Introduction of additional RFS-groups into heterocyclic compounds in the presence of CF3SO3H.
Scheme 21: Introduction of additional RFS-groups into pyrroles [82,87].
Scheme 22: By-products in reactions of pyrroles with CF3SCl [82].
Scheme 23: Reaction of aromatic iodides with CuSCF3 [93,95].
Scheme 24: Reaction of aromatic iodides with RFZCu (Z = S, Se), RF = CF3, C6F5 [93,95,96].
Scheme 25: Side reactions during trifluoromethylsulfanylation of aromatic iodides with CF3SCu [98].
Scheme 26: Reactions with in situ generated CuSCF3.
Scheme 27: Perfluoroalkylthiolation of aryl iodides with bulky RFSCu [105].
Scheme 28: In situ formation and reaction of RFZCu with aryl iodides.
Figure 6: Examples of compounds obtained using in situ generated RFZCu methodology [94].
Scheme 29: Introduction of SCF3 group into aromatics via difluorocarbene.
Scheme 30: Tetrakis(dimethylamino)ethylene dication trifluoromethyl thiolate as a stable reagent for substitut...
Scheme 31: The use of CF2=S/CsF or (CF3S)2C=S/CsF for the introduction of CF3S groups into fluorinated heteroc...
Scheme 32: One-pot synthesis of ArSCF3 from ArX, CCl2=S and KF.
Scheme 33: Reaction of aromatics with CF3S− Kat+ [115].
Scheme 34: Reactions of activated aromatic chlorides with AgSCF3/KI.
Scheme 35: Comparative CuSCF3/KI and Hg(SCF3)2/KI reactions.
Scheme 36: Me3SnTeCF3 – a reagent for the introduction of the TeCF3 group.
Scheme 37: Sandmeyer reactions with CuSCF3.
Scheme 38: Reactions of perfluoroalkyl iodides with alkali and organolithium reagents.
Scheme 39: Perfluoroalkylation with preliminary breaking of the disulfide bond.
Scheme 40: Preparation of RFS-substituted anilines from dinitrodiphenyl disulfides.
Scheme 41: Photochemical trifluoromethylation of 2,4,6-trimercaptochlorobenzene [163].
Scheme 42: Putative process for the formation of B, C and D.
Scheme 43: Trifluoromethylation of 2-mercapto-4-hydroxy-6-trifluoromethylyrimidine [145].
Scheme 44: Deactivation of 2-mercapto-4-hydroxypyrimidines S-centered radicals.
Scheme 45: Perfluoroalkylation of thiolates with CF3Br under UV irradiation.
Scheme 46: Catalytic effect of methylviologen for RF• generation.
Scheme 47: SO2−• catalyzed trifluoromethylation.
Scheme 48: Electrochemical reduction of CF3Br in the presence of SO2 [199,200].
Scheme 49: Participation of SO2 in the oxidation of ArSCF3−•.
Scheme 50: Electron transfer cascade involving SO2 and MV.
Scheme 51: Four stages of the SRN1 mechanism for thiol perfluoroalkylation.
Scheme 52: A double role of MV in the catalysis of RFI reactions with aryl thiols.
Scheme 53: Photochemical reaction of pentafluoroiodobenzene with trifluoromethyl disulfide.
Scheme 54: N- Trifluoromethyl-N-nitrosobenzene sulfonamide – a source of CF3• radicals [212,213].
Scheme 55: Radical trifluoromethylation of organic disulfides with ArSO2N=NCF3.
Scheme 56: Barton’s S-perfluoroalkylation reactions [216].
Scheme 57: Decarboxylation of thiohydroxamic esters in the presence of C6F13I.
Scheme 58: Reactions of thioesters of trifluoroacetic and trifluoromethanesulfonic acids in the presence of ar...
Scheme 59: Perfluoroalkylation of polychloropyridine thiols with xenon perfluorocarboxylates or XeF2 [222,223].
Scheme 60: Interaction of Xe(OCORF)2 with nitroaryl disulfide [227].
Scheme 61: Bi(CF3)3/Cu(OCOCH3)2 trifluoromethylation of thiophenolate [230].
Scheme 62: Reaction of fluorinated carbanions with aryl sulfenyl chlorides.
Scheme 63: Reaction of methyl perfluoromethacrylate with PhSCl in the presence of fluoride.
Scheme 64: Reactions of ArSCN with potassium and magnesium perfluorocarbanions [237].
Scheme 65: Reactions of RFI with TDAE and organic disulfides [239,240].
Scheme 66: Decarboxylation of perfluorocarboxylates in the presence of disulfides [245].
Scheme 67: Organization of a stable form of “CF3−” anion in the DMF.
Scheme 68: Silylated amines in the presence of fluoride can deprotonate fluoroform for reaction with disulfide...
Figure 7: Other examples of aminomethanols [264].
Scheme 69: Trifluoromethylation of diphenyl disulfide with PhSO2CF3/t-BuOK.
Scheme 70: Amides of trifluoromethane sulfinic acid are sources of CF3− anion.
Scheme 71: Trifluoromethylation of various thiols using “hyper-valent” iodine (III) reagent [279].
Scheme 72: Trifluoromethylation of p-nitrothiophenolate with diaryl CF3 sulfonium salts [280].
Scheme 73: Trifluoromethyl transfer from dibenzo (CF3)S-, (CF3)Se- and (CF3)Te-phenium salts to thiolates [283].
Scheme 74: Multi-stage paths for synthesis of dibenzo-CF3-thiophenium salts [61].
Shelf-stable electrophilic trifluoromethylating reagents: A brief historical perspective
- Norio Shibata,
- Andrej Matsnev and
- Dominique Cahard
Beilstein J. Org. Chem. 2010, 6, No. 65, doi:10.3762/bjoc.6.65
- , enamines, and thiolate anions with these reagents, albeit in low to moderate yields [28]. Neutral hypervalent iodine(III)–CF3 reagent Initial attempts by Yagupolskii and Umemoto to synthesize iodonium salts with a trifluoromethyl group were unsuccessful. Whilst iodonium salts including p
Graphical Abstract
Scheme 1: Preparation of the first electrophilic trifluoromethylating reagent and its reaction with a thiophe...
Scheme 2: Synthetic routes to S-CF3 and Se-CF3 dibenzochalcogenium salts.
Scheme 3: Synthesis of (trifluoromethyl)dibenzotellurophenium salts.
Scheme 4: Nitration of (trifluoromethyl)dibenzochalcogenium salts.
Scheme 5: Synthesis of a sulphonium salt with a bridged oxygen.
Scheme 6: Reactivity of (trifluoromethyl)dibenzochalcogenium salts.
Scheme 7: Pd(II)-Catalyzed ortho-trifluoromethylation of heterocycle-substituted arenes by Umemoto’s reagents....
Scheme 8: Mild electrophilic trifluoromethylation of β-ketoesters and silyl enol ethers.
Scheme 9: Enantioselective electrophilic trifluoromethylation of β-ketoesters.
Scheme 10: Preparation of water-soluble S-(trifluoromethyl)dibenzothiophenium salts.
Scheme 11: Method for large-scale preparation of S-(trifluoromethyl)dibenzothiophenium salts.
Scheme 12: Triflic acid catalyzed synthesis of 5-(trifluoromethyl)thiophenium salts.
Scheme 13: Trifluoromethylation of β-ketoesters and dicyanoalkylidenes by S-(trifluoromethyl)benzothiophenium ...
Scheme 14: Synthesis of chiral S-(trifluoromethyl)benzothiophenium salt 18 and attempt of enantioselective tri...
Scheme 15: Synthesis of O-(trifluoromethyl)dibenzofuranium salts.
Scheme 16: Photochemical O- and N-trifluoromethylation by 20b.
Scheme 17: Thermal O-trifluoromethylation of phenol by diazonium salt 19a. Effect of the counteranion.
Scheme 18: Thermal O- and N-trifluoromethylations.
Scheme 19: Method of preparation of S-(trifluoromethyl)diphenylsulfonium triflates.
Scheme 20: Reactivity of some S-(trifluoromethyl)diarylsulfonium triflates.
Scheme 21: One-pot synthesis of S-(trifluoromethyl)diarylsulfonium triflates.
Scheme 22: One-pot synthesis of Umemoto’s type reagents.
Scheme 23: Preparation of sulfonium salts by transformation of CF3− into CF3+.
Scheme 24: Selected reactions with the new Yagupolskii reagents.
Scheme 25: Synthesis of heteroaryl-substituted sulfonium salts.
Scheme 26: First neutral S-CF3 reagents.
Scheme 27: Synthesis of Togni reagents. aYield for the two-step procedure.
Scheme 28: Trifluoromethylation of C-nucleophiles with 37.
Scheme 29: Selected examples of trifluoromethylation of S-nucleophiles with 37.
Scheme 30: Selected examples of trifluoromethylation of P-nucleophiles with 35 and 37.
Scheme 31: Trifluoromethylation of 2,4,6-trimethylphenol with 35.
Scheme 32: Examples of O-trifluoromethylation of alcohols with 35 in the presence of 1 equiv of Zn(NTf2)2.
Scheme 33: Formation of trifluoromethyl sulfonates from sulfonic acids and 35.
Scheme 34: Organocatalytic α-trifluoromethylation of aldehydes with 37.
Scheme 35: Synthesis of reagent 42 and mechanism of trifluoromethylation.
Scheme 36: Trifluoromethylation of β-ketoesters and dicyanoalkylidenes with 42.
