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Search for "photooxidation" in Full Text gives 37 result(s) in Beilstein Journal of Organic Chemistry.
Photocatalytic nucleophilic addition of alcohols to styrenes in Markovnikov and anti-Markovnikov orientation
- Martin Weiser,
- Sergej Hermann,
- Alexander Penner and
- Hans-Achim Wagenknecht
Beilstein J. Org. Chem. 2015, 11, 568–575, doi:10.3762/bjoc.11.62
- mechanism (Scheme 4). Comparison of product formation after 18 h showed that the methoxy substituted product 9 was obtained in approximately double yield compared to 11. Obviously, the photooxidation of the electron-rich double bond in substrate 8 by electron transfer occured faster than the one in
- LEDs (250 mW), λ = 530 nm. Photooxidation of the substrate and reductive quenching of the photocatalyst (left) vs photoreduction of the substrate and oxidative quenching of the photocatalyst (right) give two complementary photocatalytic cycles yielding either anti-Markovnikov-type or Markovnikov-type
Graphical Abstract
Scheme 1: Photooxidation of the substrate and reductive quenching of the photocatalyst (left) vs photoreducti...
Scheme 2: Mechanism of the Markovnikov-type photocatalytic addition of methanol to 1,1-diphenylethylene (1) a...
Scheme 3: Intramolecular photocatalytic addition with substrate 3; reaction conditions: 3 (2 mM), Py (2 mM), ...
Scheme 4: Proposed mechanism of the anti-Markovnikov-type photocatalytic addition of methanol to 1,1-diphenyl...
Figure 1: Conversion of substrate 1 and formation of product 5 observed during photocatalysis with PDI in the...
Figure 2: Conversion of substrate 1 (black dashed) and formation of product 5 (red solid) observed during pho...
Figure 3: Spectra of PDI before (dotted black) and after excitation (red), then every 2 min until ground stat...
Scheme 5: Intramolecular additions of substrates 8 and 10 to demonstrate the effect of different electron den...
Electrochemical oxidation of cholesterol
- Jacek W. Morzycki and
- Andrzej Sobkowiak
Beilstein J. Org. Chem. 2015, 11, 392–402, doi:10.3762/bjoc.11.45
- studies on cholesterol oxidation may allow for significant advances in cholesterol biology and chemistry. Review General remarks A series of physiological actions in both humans and animals are caused by chemical oxidation, photooxidation or enzymatic oxidation of cholesterol. Despite the importance of
Graphical Abstract
Figure 1: Preferential sites of cholesterol electrooxidation.
Scheme 1: Functionalization of the cholesterol side chain.
Scheme 2: Oxidation of cholestane-3β,5α,6β-triol triacetate (3) with the Gif system.
Scheme 3: Electrochemical oxidation of cholesteryl acetate (1a) with dioxygen and iron–picolinate complexes.
Scheme 4: Electrochemical chlorination of cholesterol catalyzed by FeCl3.
Scheme 5: Electrochemical chlorination of Δ5-steroids.
Scheme 6: Electrochemical bromination of Δ5-steroids in different solvents.
Scheme 7: Direct electrochemical acetoxylation of cholesterol at the allylic position.
Scheme 8: Direct anodic oxidation of cholesterol in dichloromethane.
Scheme 9: A plausible mechanism of the electrochemical oxidation of cholesterol in dichloromethane.
Scheme 10: The electrochemical formation of glycosides and glycoconjugates.
Scheme 11: Efficient electrochemical oxidation of cholesterol to cholesta-4,6-dien-3-one (24).
One-pot functionalisation of N-substituted tetrahydroisoquinolines by photooxidation and tunable organometallic trapping of iminium intermediates
- Joshua P. Barham,
- Matthew P. John and
- John A. Murphy
Beilstein J. Org. Chem. 2014, 10, 2981–2988, doi:10.3762/bjoc.10.316
- novel, one-pot methodology that functionalises N-substituted tetrahydroisoquinolines by visible light-assisted photooxidation, followed by trapping of the resultant iminium ions with organometallic nucleophiles. This affords 1,2-disubstituted tetrahydroisoquinolines in moderate to excellent yields
Graphical Abstract
Figure 1: Examples of biologically active 1,2-disubstituted tetrahydroisoquinolines.
Scheme 1: Oxidative C–H functionalisation and examples of previously reported nucleophilic trappings.
Figure 2: Products from allylzinc reagent addition to 5a and 5b.
Figure 3: Proposed mechanism for formation of side-product 8a. Analogous reactivity in the formation of cycli...
Figure 4: Mechanism for dimerisation of the allylzinc halide and β-hydride addition to 5a [36].
Scheme 2: A concise synthesis of methopholine (3).
Cyclization–endoperoxidation cascade reactions of dienes mediated by a pyrylium photoredox catalyst
- Nathan J. Gesmundo and
- David A. Nicewicz
Beilstein J. Org. Chem. 2014, 10, 1272–1281, doi:10.3762/bjoc.10.128
- single electron oxidants capable of this task, we elected to employ photooxidation catalysts. Additionally, we sought to select visible light-activated organic single electron oxidants that do not readily sensitize singlet oxygen [17][18][19]. For these reasons, we were attracted to the use of
- tetrafluoroborate, which has been used with success in other photooxidation processes [23][24][25][26], was used in place of 1c, complete consumption of 2a was observed, but 3a was not produced. Once again only oxidative decomposition pathways seemed active, this time possibly due to superoxide formation. Lastly
Graphical Abstract
Figure 1: Selected examples of endoperoxide-containing natural products.
Scheme 1: Endoperoxide formation via cation radicals. In both examples, single electron oxidation is followed...
Scheme 2: Diversification strategy for endoperoxide synthesis by single electron transfer. E*red vs SCE [20].
Figure 2: ORTEP of 3a.
Scheme 3: Proposed mechanism for endoperoxide synthesis from tethered dienes.
Scheme 4: Competing formal [3,3] pathway.
On the mechanism of photocatalytic reactions with eosin Y
- Michal Majek,
- Fabiana Filace and
- Axel Jacobi von Wangelin
Beilstein J. Org. Chem. 2014, 10, 981–989, doi:10.3762/bjoc.10.97
- photocatalysts [3][4][5][6][7][8], whereas much less attention has been directed at eosin Y-catalyzed reactions. The reductive quenching pathway of eosin Y, which operates in the photooxidation of isoquinolines [9], has been studied in a single report [22]. To the best of our knowledge, related data have not
Graphical Abstract
Scheme 1: Oxidative quenching of eosin Y with arenediazonium salts and reactions of the resultant aryl radica...
Scheme 2: Proposed general reaction mechanism of eosin Y-catalyzed substitutions with arene diazonium salts.
Figure 1: UV–vis spectra of the photoborylation reaction mixture (RM).
Figure 2: Fluorescence spectra of the photoborylation reaction mixture (RM). Ex. = excitation wavelength.
Scheme 3: Acid–base behaviour of eosin Y.
Figure 3: UV–vis spectrum of p-bromobenzenediazonium tetrafluoroborate (pBrPhN2) and bispinacolato diboron (B2...
Scheme 4: Eosin Y-catalyzed and dye-free photolytic borylation.
Scheme 5: Eosin Y-catalyzed and dye-free reactions with ethyl propiolate.
Figure 4: UV–vis spectra of ortho-biphenyldiazonium tetrafluoroborate (biPhN2) in acetonitrile.
Scheme 6: Quantum yield determinations of selected visible-light-driven aromatic substitutions.
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
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).
The chemistry of amine radical cations produced by visible light photoredox catalysis
- Jie Hu,
- Jiang Wang,
- Theresa H. Nguyen and
- Nan Zheng
Beilstein J. Org. Chem. 2013, 9, 1977–2001, doi:10.3762/bjoc.9.234
- chemistries that have focused on the use of amines as a sacrificial electron donor only or as a hydrogen radical donor only will not be discussed in the review. These chemistries have been recently reviewed [22][23][35][36][37][38][39][40][41][42]. Photooxidation of amines to amine radical cations can also be
- (distonic ion) [106]. We have applied Ru(bpz)3(PF6)2-catalyzed photooxidation of N-cyclopropylanilines to induce this rearrangement reaction. The resulting distonic ion was then intercepted by alkenes to produce [3 + 2] annulation products (Scheme 32) [107]. An aryl group on the amine was required for the
- expanded the type of bonds that can be formed, particularly bonds formed asymmetrically. In summary, the utility of amine radical cations formed via photooxidation of the amines has been amply demonstrated in a number of synthetic methods. With the organic community’s increasing interest in visible light
Graphical Abstract
Scheme 1: Amine radical cations’ mode of reactivity.
Scheme 2: Reductive quenching of photoexcited Ru complexes by Et3N.
Scheme 3: Photoredox aza-Henry reaction.
Scheme 4: Formation of iminium ions using BrCCl3 as stoichiometric oxidant.
Scheme 5: Oxidative functionalization of N-aryltetrahydroisoquinolines using Eosin Y.
Scheme 6: Synthetic and mechanistic studies of Eosin Y-catalyzed aza-Henry reaction.
Scheme 7: Oxidative functionalization of N-aryltetrahydroisoquinolines using RB and GO.
Scheme 8: Merging Ru-based photoredox catalysis and Lewis base catalysis for the Mannich reaction.
Scheme 9: Merging Au-based photoredox catalysis and Lewis base catalysis for the Mannich reaction.
Scheme 10: Merging Ru-based photoredox catalysis and Cu-catalyzed alkynylation reaction.
Scheme 11: Merging Ru-based photoredox catalysis and NHC catalysis.
Scheme 12: 1,3-Dipolar cycloaddition of photogenically formed azomethine ylides.
Scheme 13: Plausible mechanism for photoredox 1,3-dipolar cycloaddition.
Scheme 14: Photoredox-catalyzed cascade reaction for the synthesis of fused isoxazolidines.
Scheme 15: Plausible mechanism for the photoredox-catalyzed cascade reaction.
Scheme 16: Photoredox-catalyzed α-arylation of glycine derivatives.
Scheme 17: Photoredox-catalyzed α-arylation of amides.
Scheme 18: Intramolecular interception of iminium ions by sulfonamides.
Scheme 19: Intramolecular interception of iminium ions by alcohols and sulfonamides.
Scheme 20: Intermolecular interception of iminium ions by phosphites.
Scheme 21: Photoredox-catalyzed oxidative phosphonylation by Eosin Y.
Scheme 22: Conjugated addition of α-amino radicals to Michael acceptors.
Scheme 23: Conjugated addition of α-amino radicals to Michael acceptors assisted by a Brønsted acid.
Scheme 24: Conjugated addition of α-amino radicals derived from anilines to Michael acceptors.
Scheme 25: Oxygen switch between two pathways involving α-amino radicals.
Scheme 26: Interception of α-amino radicals by azodicarboxylates.
Scheme 27: α-Arylation of amines.
Scheme 28: Plausible mechanism for α-arylation of amines.
Scheme 29: Photoinduced C–C bond cleavage of tertiary amines.
Scheme 30: Photoredox cleavage of C–C bonds of 1,2-diamines.
Scheme 31: Proposed mechanism photoredox cleavage of C–C bonds.
Scheme 32: Intermolecular [3 + 2] annulation of cyclopropylamines with olefins.
Scheme 33: Proposed mechanism for intermolecular [3 + 2] annulation.
Scheme 34: Photoinduced clevage of N–N bonds of aromatic hydrazines and hydrazides.
Flow photochemistry: Old light through new windows
- Jonathan P. Knowles,
- Luke D. Elliott and
- Kevin I. Booker-Milburn
Beilstein J. Org. Chem. 2012, 8, 2025–2052, doi:10.3762/bjoc.8.229
Graphical Abstract
Figure 1: An immersion-well batch reactor with 125 W medium pressure Hg lamp.
Figure 2: Transmission profile of a 0.05 M solution, ε = 200 M−1 cm−1.
Figure 3: Schematic of a typical microflow photochemical reactor (above) and detail of a triple-channel micro...
Figure 4: Schematic of a typical macroflow photochemical reactor (above) and images of the FEP photochemical ...
Scheme 1: [2 + 2] photocycloadditions of enones with enol derivatives.
Scheme 2: Competing reactions in an intramolecular [2 + 2] photocycloaddition.
Scheme 3: Diastereocontrolled cycloaddition of a cyclic enone with cyclopentene.
Scheme 4: Comparison of yields and reaction times for a batch reactor with a microflow system.
Scheme 5: Intramolecular [2 + 2] photocycloaddition.
Scheme 6: Paterno–Büchi reaction of benzophenone with an allylic alcohol.
Scheme 7: Photooxygenation of cyclopentadiene.
Scheme 8: Preparation of the anthelmintic ascaridole 23.
Scheme 9: Production of rose oxide 27 from (−)-β-citronellol (24).
Scheme 10: Photocatalytic alkylation of benzylamine.
Scheme 11: Photocatalytic reduction of 4-nitroacetophenone.
Scheme 12: Conversion of L-lysine to L-pipecolinic acid.
Scheme 13: Photocatalytic hydrodehalogenation.
Scheme 14: Photocatalytic aza-Henry reactions.
Scheme 15: Photocatalytic α-alkylation of aliphatic ketones.
Scheme 16: Decarboxylative photochemical additions.
Scheme 17: Photochemical addition of isopropanol to furanones.
Scheme 18: Photochemical addition of methanol to limonene.
Scheme 19: Light-promoted reduction of flavone.
Scheme 20: Photoreduction of benzophenone with benzhydrol.
Scheme 21: Barton reaction in a microflow system.
Scheme 22: Microflow synthesis of vitamin D3.
Scheme 23: photochemical chlorination of cyclohexane.
Scheme 24: photochemical cyanation of pyrene.
Scheme 25: Intermolecular [2 + 2] cycloaddition of maleimide (76) and intramolecular [2 + 2] cycloaddition of ...
Scheme 26: Intramolecular [5 + 2] cycloaddition of maleimide under flow conditions.
Scheme 27: Intramolecular [5 + 2] cycloaddition as a key step in the synthesis of (±)-neostenine.
Scheme 28: In situ generation of a thioaldehyde by photolysis of a phenacyl sulfide.
Scheme 29: Photodimerisation of maleic anhydride.
Scheme 30: [2 + 2] cycloaddition of a chiral enone with ethylene.
Scheme 31: Intramolecular [2 + 2] cycloaddition of a cyclopentenone.
Scheme 32: Photochemical Wolff rearrangement and cyclisation to β-lactams.
Scheme 33: Photochemical rearrangement of aryl azides.
Scheme 34: Rearrangement of quinoline N-oxides to quinolones.
Scheme 35: Photochemical rearrangement of cyclobutenones.
Scheme 36: Photoisomerisation en route to a vitamin-D derivative.
Scheme 37: Schematic of the Seeberger photooxygenation apparatus and sensitised photooxygenation of citronello...
Scheme 38: Sensitised photooxygenation of dihydroartemisinic acid.
Scheme 39: Photochemical preparation of CpRu(MeCN)3PF6.
Scheme 40: In situ photochemical generation and reaction of a [CpRu]+ catalyst.
Scheme 41: Intermolecular alkene–alkyne coupling with photogenerated catalyst.
Scheme 42: PET deoxygenation of nucleosides.
Scheme 43: Photochemical defluorination of DABFT.
Scheme 44: Aromatic azide reduction by visible-light-mediated photocatalysis.
Scheme 45: Examples of visible-light-mediated reactions.
Scheme 46: Visible-light-mediated formation of iminium ions.
Scheme 47: Examples of visible-light-mediated photocatalytic reactions.
Scheme 48: Anhydride formation from a visible-light-mediated process.
Scheme 49: Light-mediated conjugate addition of glycosyl bromide 141 to acrolein.
Scheme 50: Visible-light-mediated photocyclisation to [5]helicene.
Synthesis and photooxidation of styrene copolymer bearing camphorquinone pendant groups
- Branislav Husár,
- Norbert Moszner and
- Ivan Lukáč
Beilstein J. Org. Chem. 2012, 8, 337–343, doi:10.3762/bjoc.8.37
- formed in irradiated films of styrene copolymers with pendant BZ groups leads to crosslinking, only small molecular-weight changes in irradiated MCQ/S were observed. Keywords: camphorquinone; 1,2-diketone; (±)-10-methacryloyloxycamphorquinone; photooxidation; polystyrene; Introduction Camphorquinone
- % from UV–vis. MCQ is therefore more reactive than styrene, which is in agreement with the copolymerization parameters of structurally similar monomers. Photooxidation of MCQ/S Since it is difficult to follow the structural changes of the CQ structures of the MCQ/S copolymer during photochemical
- CQ photooxidation in PS are summarized in Scheme 3 [21]. The addition of molecular oxygen to the excited n→π* triplet state of ketones and 1,2-diketones to form 1,4-biradicals is a generally accepted mechanism, which has been theoretically treated and reviewed [37]. The oxygen atom released during
Graphical Abstract
Scheme 1: Photoperoxidation of BZ in an aerated glassy polymer matrix.
Scheme 2: Synthesis of MCQ from (±)-10-camphorsulfonic acid (1). Only one enantiomer of each compound is depi...
Scheme 3: Photooxidation of CQ in aerated glassy PS matrix.
Figure 1: FTIR spectra of MCQ/S film after irradiation in a carousel for the indicated periods. Spectrum of PS...
Figure 2: UV–vis spectra of MCQ/S film after irradiation in a carousel apparatus for the indicated periods.
Scheme 4: Proposed mechanism of MCQ/S photochemistry.
Synthetic incorporation of Nile Blue into DNA using 2′-deoxyriboside substitutes: Representative comparison of (R)- and (S)-aminopropanediol as an acyclic linker
- Daniel Lachmann,
- Sina Berndl,
- Otto S. Wolfbeis and
- Hans-Achim Wagenknecht
Beilstein J. Org. Chem. 2010, 6, No. 13, doi:10.3762/bjoc.6.13
- Ered −0.3 V (vs. NHE), the excited state potential is estimated to be E*red = 2.2 eV [17]. Hence, a photooxidation of guanine is highly favorable because the oxidation potential of guanine is only ~1.3–1.4 V [44]. Hence sequence-dependent fluorescence quenching of the Nile Blue dye in DNA was expected
Graphical Abstract
Scheme 1: Chirality of C-3 of natural 2′-deoxyribofuranosides (left) in comparison with the acyclic D-threoni...
Scheme 2: Synthesis of the R-configured DNA building block 3 and postsynthetic click ligation of the Nile Blu...
Figure 1: UV–vis absorption spectra of single-stranded DNA1 and DNA2, and the corresponding duplexes DNA1Y an...
Figure 2: Fluorescence spectra of single-stranded DNA1 and DNA2, and corresponding duplexes DNA1Y and DNA2Y (...
Figure 3: Models for DNA1A bearing the (R)-3-amino-1,2-propanediol linker (left) and the corresponding duplex...
Reversible intramolecular photocycloaddition of a bis(9-anthrylbutadienyl)paracyclophane – an inverse photochromic system. (Photoactive cyclophanes 5)
- Henning Hopf,
- Christian Beck,
- Jean-Pierre Desvergne,
- Henri Bouas-Laurent,
- Peter G. Jones and
- Ludger Ernst
Beilstein J. Org. Chem. 2009, 5, No. 20, doi:10.3762/bjoc.5.20
- bubbled through the solution to prevent photooxidation, and the spectra were recorded at various time intervals (Figure 7). Three isosbestic points at 220, 289, and 329 nm were observed as well as new absorptions at 306 nm and in the far UV. Similar features were noted for the MCH solutions. At that
Graphical Abstract
Figure 1: Schematic representation of a photochromic system. The reverse reaction can be a photochemical or t...
Figure 2: Photochromic reaction of pseudo-gem disubstituted tetraene [2.2]cyclophane 1 in acetonitrile, conc....
Figure 3: Molecular structure of 4,13-bis[(1E,3E)-4-(9-anthracenyl)-buta-1,3-dienyl][2.2]paracyclophane (2).
Scheme 1: Preparation of 2 (last step), using the Wittig reaction. The preparation of 3 has been described in...
Figure 4: Molecular structure of 2 in the crystal. Radii are arbitrary; only selected H atoms are shown.
Figure 5: Projection of the molecular structure of 2 exhibiting the closest internuclear distances (distances...
Figure 6: Electronic absorption spectra of 2 (conc. ca 10−4 M) in MCH (full line) and CH3CN (dotted line) at ...
Figure 7: Irradiation of 2 (2.6 × 10−5 M) in CH3CN at 400 nm at 20 °C. The spectra were recorded at various t...
Figure 8: Irradiation at 306 nm of the photoproduct 4 obtained at 400 nm in the same setup; the spectra were ...
Figure 9: Reversibility of the formation of the photoproduct 4 at 400 nm (40 min) and photodissociation of 4 ...
Figure 10: 1H NMR spectra (400 MHz, CDCl3). A: Compound 2, B: Compound 4.
Figure 11: Proposed structure of 4 (1,4 : 2′,3′-cycloadduct).
EcoScale, a semi- quantitative tool to select an organic preparation based on economical and ecological parameters
- Koen Van Aken,
- Lucjan Strekowski and
- Luc Patiny
Beilstein J. Org. Chem. 2006, 2, No. 3, doi:10.1186/1860-5397-2-3
- , mutagenic, teratogenic, corrosive, lachrymatic, highly flammable or explosive, among other things. In addition, the hazard can increase over time, and photooxidation of ether to generate explosive peroxides is a good example. It must also be emphasised that it takes a long time before the safety profiles of
Graphical Abstract
Scheme 1: Reduction of nitrobenzene to aniline [23]
Scheme 2: Oxidation of benzyl chloride to benzoic acid [24]
Scheme 3: Synthesis of benzamide [25]
Scheme 4: Synthesis of benzamide using HMDS [26]
