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Search for "UV irradiation" in Full Text gives 127 result(s) in Beilstein Journal of Organic Chemistry.
Deep-blue emitting 9,10-bis(perfluorobenzyl)anthracene
- Long K. San,
- Sebastian Balser,
- Brian J. Reeves,
- Tyler T. Clikeman,
- Yu-Sheng Chen,
- Steven H. Strauss and
- Olga V. Boltalina
Beilstein J. Org. Chem. 2025, 21, 515–525, doi:10.3762/bjoc.21.39
- photoirradiation of the ANTH solution, a set of new resonances (δ = 6.92 (m, 2H), 6.81 (m, 2H), and 4.55 (s, 1H) ppm) appeared and increased in intensity relative to the ANTH resonances. The new photoproduct was identified as a dimer, dianthracene, which had previously been shown to form under anaerobic UV
- irradiation [37]. Notably, the apparent absence of the photodimer in the case of 9,10-ANTH(BnF)2 is likely due to the steric hindrance of the bulky perfluorobenzyl groups in the 9- and 10-positions on the ANTH core. Conclusion The perfluorobenzylation of ANTH and ANTH(Br)2 was performed for the first time
Graphical Abstract
Scheme 1: List of reactions, experimental conditions and yields studied in this work.
Figure 1: Top: 379 MHz 19F NMR spectrum of 9,10-ANTH(BnF)2 in CDCl3. Bottom: absorption (aerobic, solid line)...
Figure 2: Top: X-ray structure of 9,10-ANTH(BnF)2, thermal ellipsoids 50% probability. Bottom: a view down th...
Figure 3: Absorption spectra of ANTH and 9,10-ANTH(BnF)2 in CH2Cl2 recorded over the period of 53 days in air...
Figure 4: Direct analysis in real time (DART) positive ion mass spectrum of the photoirradiated 9,10-ANTH(BnF)...
Figure 5: The % remaining of ANTH and 9,10-ANTH(BnF)2 dissolved in CDCl3 upon irradiation. Resonances δ = 7.4...
Organocatalytic kinetic resolution of 1,5-dicarbonyl compounds through a retro-Michael reaction
- James Guevara-Pulido,
- Fernando González-Pérez,
- José M. Andrés and
- Rafael Pedrosa
Beilstein J. Org. Chem. 2025, 21, 473–482, doi:10.3762/bjoc.21.34
- a one dm path length, and concentration was given in grams per 100 mL. TLC analysis was performed on glass-backed plates coated with silica gel 60 and an F254 indicator and visualized by either UV irradiation or staining with phosphomolybdic acid solution. Flash chromatography uses silica gel (230
Graphical Abstract
Scheme 1: Previous work.
Scheme 2: Hypothesis, retro-Michael reaction, and its application in kinetic resolution.
Scheme 3: Model reaction.
Scheme 4: Kinetic resolution of the Michael adduct 1.
Scheme 5: Chemical correlation of 3 with 19.
Scheme 6: Epimerization of the anti-1 adduct promoted by A.
Photomechanochemistry: harnessing mechanical forces to enhance photochemical reactions
- Francesco Mele,
- Ana M. Constantin,
- Andrea Porcheddu,
- Raimondo Maggi,
- Giovanni Maestri,
- Nicola Della Ca’ and
- Luca Capaldo
Beilstein J. Org. Chem. 2025, 21, 458–472, doi:10.3762/bjoc.21.33
- rearrangements. Most organic molecules are colorless and, in fact, do not absorb visible light: highly energetic UV irradiation is typically needed. A milder approach is offered by photocatalytic approaches. Here, a photocatalyst is added to the reaction mixture to convert light energy into chemical potential to
- zinc cations to align 1.1 through the formation of hydrogen-bonded coordination complexes. Thus, when a single crystal of the [Zn(bpe)2(H2O)4](NO3)2·8/3H2O·2/3bpe complex was exposed to UV irradiation (dark blue phosphor lamps, λ = 350 nm) for 25 h, only 46% conversion to 1.2 was observed via 1H NMR
- coordinative bonds on one side and hydrogen bonds on the other. Surprisingly, when the crystals were manually ground for 5 min before irradiation, the conversion to dimer 1.2 remarkably increased to 88% in only 4 h of UV irradiation time. Overall, the role of manual grinding was not only to increase the
Graphical Abstract
Figure 1: The Grotthuss–Draper, Einstein–Stark, and Beer–Lambert laws. T: transmittance; ε: molar attenuation...
Figure 2: The benefits of merging photochemistry with mechanochemical setups (top). Most common setups for ph...
Scheme 1: Mechanochemically triggered pedal-like motion in solid-state [2 + 2] photochemical cycloaddition fo...
Scheme 2: Mechanically promoted [2 + 2] photodimerization of trans-1,2-bis(4-pyridyl)ethylene (2.1) via supra...
Scheme 3: Photo-thermo-mechanosynthesis of quinolines [65].
Scheme 4: Study of the mechanically assisted [2 + 2] photodimerization of chalcone [66].
Scheme 5: Liquid-assisted vortex grinding (LAVG) for the synthesis of [2.2]paracyclophane [68].
Scheme 6: Photomechanochemical approach for the riboflavin tetraacetate-catalyzed photocatalytic oxidation of...
Scheme 7: Photomechanochemical oxidation of 1,2-diphenylethyne to benzil. The photo in Scheme 7 was republished with ...
Scheme 8: Photomechanochemical borylation of aryldiazonium salts. The photo in Scheme 8 was reproduced from [72] (© 2017 ...
Scheme 9: Photomechanochemical control over stereoselectivity in the [2 + 2] dimerization of acenaphthylene. ...
Scheme 10: Photomechanochemical synthesis of polyaromatic compounds using UV light. The photo in Scheme 10 was reproduc...
Scheme 11: Mechanically assisted photocatalytic reactions: A) atom-transfer-radical addition, B) pinacol coupl...
Scheme 12: Use of mechanoluminescent materials as photon sources for photomechanochemistry. SAOED: SrAl2O4:Eu2+...
Figure 3: SWOT (strengths, weaknesses, opportunities, threats) analysis of photomechanochemistry.
Effect of substitution position of aryl groups on the thermal back reactivity of aza-diarylethene photoswitches and prediction by density functional theory
- Misato Suganuma,
- Daichi Kitagawa,
- Shota Hamatani and
- Seiya Kobatake
Beilstein J. Org. Chem. 2025, 21, 242–252, doi:10.3762/bjoc.21.16
- the absorption spectra upon UV irradiation. Notably, compound N4 turns bright yellow under UV light, adding a new color to the photochromic reaction of azadiarylethenes. The analysis of the thermal back reaction revealed activation parameters and highlighted the influence of the substitution position
Graphical Abstract
Scheme 1: Photochromic reaction of aza-diarylethene derivatives N1–N4 and I1–I4 investigated in this work.
Figure 1: Absorption spectral changes of (a) N3 and (b) I3 in n-hexane at 253 K for N3 and 203 K for I3: open...
Figure 2: Absorbance decay curves and first-order kinetics profiles for (a,b) N3 and (d,e) I3 in n-hexane at ...
Figure 3: Visualization of the difference between ΔG‡(calcd) and ΔG‡(exp) for N1–N4 and I1–I4 by calculation ...
Scheme 2: Synthetic route to aza-diarylethenes N4 and I1–I4.
Cyclodextrin-based rotaxanes for polymer materials: challenge on simultaneous realization of inexpensive production and defined structures
- Yosuke Akae
Beilstein J. Org. Chem. 2024, 20, 3026–3049, doi:10.3762/bjoc.20.252
- (Figure 5A) [56]. In the structure, α-CD was located on the trans-azobenzene moiety before ultraviolet (UV) irradiation, after which it moved to the methylene moiety based on the cis-isomerization of the azobenzene by UV irradiation. After the azobenzene moiety was moved back to the trans-isomer via
Graphical Abstract
Figure 1: Overview of the CD-based rotaxane as a polymer material covered in this review.
Figure 2: CD structure.
Figure 3: Typical pathway for synthesizing CD-based rotaxanes.
Scheme 1: (A) Synthesis of α-CD-based [2]rotaxane via a metal–ligand complex. (B) Chemical structures of meth...
Scheme 2: Synthesis of α-CD-based polyrotaxane.
Scheme 3: Facile [3]rotaxane synthesis by the urea end-capping method.
Figure 4: (A) Single-crystal structure of α-CD-based [3]rotaxane 3 and PMα-CD-based [3]rotaxane 4. (B) Schema...
Figure 5: Structural control of CD-based [2]rotaxane via (A) light irradiation and (B) light irradiation and ...
Figure 6: Relationship among the plus–minus signs of ICD, the position of the guest molecule, and the axis of...
Figure 7: Structural control of CD-based rotaxane via (A) redox reaction and (B) in a solvent.
Scheme 4: (A) Synthesis of pseudopolyrotaxane bearing an ABA triblock copolymer as an axle. (B) Two synthetic...
Scheme 5: Slippage of size-complementary rotaxanes.
Figure 8: (A) Reversible formation of the CD-based [2]rotaxane. (B) Deslipping reaction of the CD-based size-...
Figure 9: (A) Chemical structures of [3]rotaxanes 2 and 3. (B) Schematic of the deslipping reaction of [3]rot...
Figure 10: (A) Modification of the axle ends of [3]rotaxane by (1) bromination and (2) the Suzuki coupling rea...
Figure 11: (A) ICD spectra of [3]rotaxanes bearing acylated (top) and conventional (bottom) CDs. (B) Schematic...
Figure 12: Synthesis of macromolecular[3]rotaxane via a size-complementary protocol.
Figure 13: Conjugated polymer insulated by (A) β-CD. (B) Triphenylamine-substituted β-CD.
Figure 14: Synthesis of the VSC and successive rotaxane-crosslinked polymer (RCP) preparation.
Figure 15: (A) Chemical structure of the [3]rotaxane crosslinker (RC). (B) Schematic of the synthesis and de-c...
Figure 16: (A) Random vinylation of the CD-based [3]rotaxane; (B) Schematic of the reaction between α-CD and m...
Figure 17: (A) Aggregation of CD-based [3]rotaxane. (B) Schematic of the plausible mechanism of the aggregatio...
N-Glycosides of indigo, indirubin, and isoindigo: blue, red, and yellow sugars and their cancerostatic activity
- Peter Langer
Beilstein J. Org. Chem. 2024, 20, 2840–2869, doi:10.3762/bjoc.20.240
- influenced by UV irradiation. Kornienko et al. reported the synthesis and antiproliferative activity of non-glycosylated oxoindirubin Z-41e in 54% yield by reaction of cumaran-3-one with isatin under conditions similar to those employed by us (Scheme 26) [40]. However, the reaction time was much longer (24
Graphical Abstract
Scheme 1: Structures of indigo (1a), indirubin (2a) and isoindigo (3a).
Scheme 2: Structures of akashins A–C.
Scheme 3: Synthesis of 5b. Reagents and conditions: i) TMSOTf, 4 Å MS, CH2Cl2, −20 °C, 1.5 h, then 20 °C, 8–1...
Scheme 4: Synthesis of 7c. Reagents and conditions: i) TMSOTf, 4 Å MS, CH2Cl2, −18 °C, 3 h; then: TMSOTf, 4 Å...
Scheme 5: Synthesis of 1d. Reagents and conditions: i) chloroacetic acid, Na2CO3, reflux, 6 h; ii) Ac2O, NaOA...
Scheme 6: Synthesis of 10e. Reagents and conditions: i) p-TsOH·H2O, acetonitrile, MeOH, 1 d; ii) NIS, PPh3, D...
Scheme 7: Synthesis of akashins A–C. Reagents and conditions: i) TMSOTf, 4 Å MS, CH2Cl2, −18 to 20 °C, 15 h; ...
Scheme 8: Synthesis of 5d. Reagents and conditions: i) KMnO4, AcOH, high-power-stirring (12.000 rot/min), 20 ...
Scheme 9: Possible mechanism of the formation of 5c.
Scheme 10: Synthesis of 7d. Reagents and conditions: i) 1) CH2Cl2, 2) Me3SiI, 20 °C, 30 min, 3) 0 °C, 30 min, ...
Scheme 11: Synthesis of α-15b. Reagents and conditions: i) 1) CH2Cl2, 2) Me3SiI, 20 °C, 30 min, 3) 0 °C, 30 mi...
Scheme 12: Synthesis of isatin-N-glycosides 16a–f. Reagents and conditions: i) PhNH2, EtOH, 20 °C, 12 h; ii) Ac...
Scheme 13: Synthesis of 17–21. Reagents and conditions: i) Na2CO3, MeOH, 20 °C, 4 h.
Scheme 14: Synthesis of indirubin-N-glycosides α-17a and α-17b.
Scheme 15: Synthesis of β-17f. Reagents and conditions: i) 1) Na2CO3, MeOH, 20 °C, 4 h, 2) Ac2O/pyridine 1:1, ...
Scheme 16: Synthesis of β-24a. Reagents and conditions: i) n-PrOH, H2O, formic acid (buffer, 100 mM), 2 h, 65 ...
Scheme 17: Synthesis of isatin-N-glycosides 23b–g and 24b–g.
Scheme 18: Synthesis of β-29a,b. Reagents and conditions: i) EtOH, 20 °C, 12 h; ii) DDQ, dioxane, 20 °C, 12 h;...
Scheme 19: Synthesis of β-31a. Reagents and conditions: i) Na2SO3, dioxane, H2O, 110 °C, 2 d; ii) piperidine, ...
Scheme 20: Synthesis of 33a–d. Reagents and conditions: i) Ac2O, AcOH, NaOAc, 80 °C, 1 h; ii) 1) NaOMe, anhydr...
Scheme 21: Indirubins 34 and 35.
Scheme 22: Synthesis of 36f. Reagents and conditions: i) NaOH, H2O, 20 °C, 5 h; ii) HCl, NaNO2, H2O, −14 °C; i...
Scheme 23: Synthesis of 38a–h. Reagents and conditions: i) 1) 0.1 equiv NaOMe, MeOH, 20 °C, 15–20 min, 2) HOAc...
Scheme 24: Synthesis of 40a–h. Reagents and conditions: i) method A: EtOH/THF, cat. KOt-Bu, 20 °C, 3–4.5 h; me...
Scheme 25: Synthesis of 41a–d. Reagents and conditions: i) Ac2O, AcOH, NaOAc, 80 °C, 1 h.
Scheme 26: Synthesis of 41e. Reagents and conditions: i) AcOH, NaOAc, 110 °C, 24 h.
Scheme 27: Synthesis of E-β-43a–e and E-β-44a,b. Reagents and conditions: i) 1) NEt3, EtOH, 20 °C, 12 h, 2) DM...
Scheme 28: Synthesis of E-43f. Reagents and conditions: i) Na2CO3, MeOH, 20 °C, 6–24 h.
Scheme 29: Synthesis of 46a–m. Reagents and conditions: i) NEt3 (1 equiv), EtOH, 20 °C, 6–10 h; ii) MsCl, NEt3...
Scheme 30: Synthesis of 48a–d. Reagents and conditions: i) AcOH/Ac2O, NaOAc, 60 °C, 3–4 h.
Scheme 31: Synthesis of 48e. Reagents and conditions: i) NaOAc, AcOH, 110 °C, 24 h.
Scheme 32: Synthesis of β-49a,b. Reagents and conditions: i) AcOH/Ac2O, NaOAc, 60 °C, 3–4 h.
Scheme 33: Synthesis of β-54a,b. Reagents and conditions: i) 1) NaH, DMF, 0 °C, 15 min, 2) β-51a,b, 20 °C, 3 h...
Scheme 34: Synthesis of 54c–l. The yields refer to the yields of the first and second condensation step for ea...
Scheme 35: Synthesis of 57a–c and 58a–d. Reagents and conditions: i) HCl (conc.), AcOH, reflux, 24 h; ii) 1) B...
Scheme 36: Synthesis of 59a–e and 60a–e. Reagents and conditions: i) P(NEt2)3 (1.1 equiv), CH2Cl2, −78 °C to 2...
Scheme 37: Synthesis of 61a–d and 62a–d. Reagents and conditions: i) P(NEt2)3 (1.1 equiv), CH2Cl2, −78 °C to 2...
Scheme 38: Synthesis of β-64a–e and α-64a. Reagents and conditions: i) AcOH, Ac2O, NaOAc, 90 °C, 6 h.
Scheme 39: Synthesis of β-72a. Reagents and conditions: i) 66, EtOH, 20 °C, 12 h; ii) DDQ, dioxane, 20 °C, 12 ...
Scheme 40: Synthesis of β-72b.
Scheme 41: Synthesis of β-74a–c. Reagents and conditions: i) AcOH, Ac2O, NaOAc, 130 °C, 2 d.
Scheme 42: Synthesis of β-77. Reagents and conditions: i) 1) NEt3, EtOH, 20 °C, 12 h, 2) DMAP, NEt3, MsCl, 0 °...
Scheme 43: Synthesis of β-81a–f and β-80g. Reagents and conditions: i) AcOH, 80 °C, 1–3 h; ii) benzene, PTSA, ...
Scheme 44: Synthesis of 84a. Reagents and conditions: i) benzene, AlCl3, 20 °C, 10 min; ii) MeOH, NaOMe, 12 h,...
Scheme 45: Synthesis of 84b–l. The yields refer to the yields of the condensation and the deprotection step fo...
Photoluminescence color-tuning with polymer-dispersed fluorescent films containing two fluorinated diphenylacetylene-type fluorophores
- Kazuki Kobayashi,
- Shigeyuki Yamada,
- Motohiro Yasui and
- Tsutomu Konno
Beilstein J. Org. Chem. 2024, 20, 2682–2690, doi:10.3762/bjoc.20.225
- ) irradiation (λex = 365 nm). (c) A PL color diagram defined by the Commission Internationale de l'Eclairage (CIE). (a) PL spectra of PMMA dispersion films containing 1 wt % of blue fluorophore 1a and green–yellow fluorophore 1c in various weight ratios. (b) Photographs of the PMMA dispersion films under UV
- films under UV irradiation (λex = 365 nm). (c) A CIE color diagram of the PL color of PMMA dispersion films containing 1a and 1f in various weight ratios. Photophysical data of compounds 1a–g contained in a PMMA dispersion film. Photophysical data of PMMA dispersion films containing 1 wt % of blue
- fluorinated diphenylacetylenes and photoluminescence (PL) color in their crystalline states. (a) PL spectra of the donor–π–acceptor (D–π–A)-type diphenylacetylene compounds 1a–g contained in a poly(methyl methacrylate) (PMMA) dispersion film. (b) Photographs of the PMMA dispersion films under ultraviolet (UV
Graphical Abstract
Figure 1: (a) Reported photophysics of diphenylacetylene after photoexcitation. (b) Our molecular design to s...
Figure 2: Relationship between the molecular structure of fluorinated diphenylacetylenes and photoluminescenc...
Figure 3: (a) PL spectra of the donor–π–acceptor (D–π–A)-type diphenylacetylene compounds 1a–g contained in a...
Figure 4: (a) PL spectra of PMMA dispersion films containing 1 wt % of blue fluorophore 1a and green–yellow f...
Figure 5: (a) PL spectra of PMMA dispersion films containing 1 wt % of blue fluorophore 1a and yellow fluorop...
Understanding X-ray-induced isomerisation in photoswitchable surfactant assemblies
- Beatrice E. Jones,
- Camille Blayo,
- Jake L. Greenfield,
- Matthew J. Fuchter,
- Nathan Cowieson and
- Rachel C. Evans
Beilstein J. Org. Chem. 2024, 20, 2005–2015, doi:10.3762/bjoc.20.176
- on their own and in mixed micelles with lipids, on irradiation with either UV or blue light [21][22]. In addition, Ober et al. showed that in-situ UV irradiation stimulates a steady decrease in bilayer thickness for vesicles formed using Azo-modified phosphatidylcholine lipids, due to the shorter
- change in the SAXS profile from the AzoTAB (Figure 1c), resulting in a steady decrease in the scattering intensity and a shift in the Guinier plateau to higher Q values. These changes are visible within 10 minutes of UV irradiation and stabilise with no further structural changes after around 20 minutes
- explained by an increased tail-group volume of the Z isomer, which favours a higher spontaneous curvature in the amphiphile packing [4]. Similarly, the SAXS signal for AAPTAB shows a sequential change on UV irradiation (Figure 1d), reaching an equilibrium state after 40 minutes. Model fitting indicates that
Graphical Abstract
Figure 1: E–Z isomerisation of (a) AzoTAB and (b) AAPTAB under UV light (365 nm) results in a change in shape...
Figure 2: SAXS curves for AzoTAB (50 mM in water) showing the transition from the Z-rich PSS to the E-rich st...
Figure 3: SAXS curves for the Z-rich PSS of AAPTAB (50 mM) in (a) water (H2O) and (b) deuterium dioxide (D2O)...
Figure 4: Addition of excess acid (pH = 0.4) induces Z–E isomerisation in AzoTAB and AAPTAB. UV–vis absorbanc...
Figure 5: Effect of X-ray exposure time on high-concentration samples of AAPTAB in water, (a) 10 wt % and (b)...
1,2-Difluoroethylene (HFO-1132): synthesis and chemistry
- Liubov V. Sokolenko,
- Taras M. Sokolenko and
- Yurii L. Yagupolskii
Beilstein J. Org. Chem. 2024, 20, 1955–1966, doi:10.3762/bjoc.20.171
- fluorinated ones, occurred similar to HF addition [90]. Miscellaneous additions: In reference [91], the addition of trichlorosilane to 1,2-difluoroethylene (Scheme 13) was reported by the Haszeldine group. The reaction under UV irradiation produced the corresponding trichlorosilane in 85% yield, and the
- 1,2-difluoroethylene isomer (E and/or Z) was used. It was mentioned that the addition products were obtained as a mixture of diastereomers (Scheme 15). Tetramethyldiarsine was shown to react with (Z/E)-1,2-difluoroethylene under UV irradiation, yielding the product as a mixture of the racemate and the
- hexafluorodiacetyl under UV irradiation, yielding a mixture of five products, regardless of the configuration of the starting 1,2-difluoroethylene, in a ratio of 8.8:2.0:1.2:1.2:1.0 in 85% and 92% yield for the Z- and E-olefin, respectively (Scheme 23) [48]. Interestingly, the formation of [4 + 2]-adducts in this
Graphical Abstract
Scheme 1: 1,2-Difluoroethylene synthesis from HFO-1123.
Scheme 2: 1,2-Difluoroethylene synthesis from CFC-112 and HCFC-132.
Scheme 3: 1,2-Difluoroethylene synthesis from HFC-143.
Scheme 4: 1,2-Difluoroethylene synthesis from HCFC-142 via HCFC-142a.
Scheme 5: 1,2-Difluoroethylene synthesis from CFO-1112.
Scheme 6: 1,2-Difluoroethylene synthesis from 1,2-dichloroethylene.
Scheme 7: 1,2-Difluoroethylene synthesis from perfluoropropyl vinyl ether.
Scheme 8: Deuteration reaction of 1,2-difluoroethylene.
Scheme 9: Halogen addition to 1,2-difluoroethylene.
Scheme 10: Hypohalite addition to 1,2-difluoroethylene.
Scheme 11: N-Bromobis(trifluoromethyl)amine addition to 1,2-difluoroethylene.
Scheme 12: N-Chloroimidobis(sulfonyl fluoride) addition to 1,2-difluoroethylene.
Scheme 13: Trichlorosilane addition to 1,2-difluoroethylene.
Scheme 14: SF5Br addition to 1,2-difluoroethylene.
Scheme 15: PCl3/O2 addition to 1,2-difluoroethylene.
Scheme 16: Reaction of tetramethyldiarsine with 1,2-difluoroethylene.
Scheme 17: Reaction of trichlorofluoromethane with 1,2-difluoroethylene.
Scheme 18: Addition of perfluoroalkyl iodides to 1,2-difluoroethylene.
Scheme 19: Cyclopropanation of 1,2-difluoroethylene.
Scheme 20: Diels–Alder reaction of 1,2-difluoroethylene and hexachlorocyclopentadiene.
Scheme 21: Cycloaddition reaction of 1,2-difluoroethylene and fluorinated ketones.
Scheme 22: Cycloaddition reaction of 1,2-difluoroethylene and perfluorinated aldehydes.
Scheme 23: Photochemical cycloaddition of 1,2-difluoroethylene and hexafluorodiacetyl.
Scheme 24: Reaction of 1,2-difluoroethylene with difluorosilylene.
Scheme 25: Reaction of 1,2-difluoroethylene with aryl iodides.
Switchable molecular tweezers: design and applications
- Pablo Msellem,
- Maksym Dekthiarenko,
- Nihal Hadj Seyd and
- Guillaume Vives
Beilstein J. Org. Chem. 2024, 20, 504–539, doi:10.3762/bjoc.20.45
Graphical Abstract
Figure 1: Principle of switchable molecular tweezers.
Figure 2: Principle of pH-switchable molecular tweezers 1 [19].
Figure 3: a) pH-Switchable tweezers 2 substituted with alkyl chains as switchable lipids. b) Schematic depict...
Figure 4: Modification of spectral properties of 3 by controlled induction of Pt–Pt interactions.
Figure 5: Conformational switching of di(hydroxyphenyl)pyrimidine-based tweezer 4 upon alkylation or fluoride...
Figure 6: Hydrazone-based pH-responsive tweezers 5 for mesogenic modulation.
Figure 7: pH-Switchable molecular tweezers 6 bearing acridinium moieties.
Figure 8: a) Terpyridine and pyridine-hydrazone-pyridine analogs molecular tweezers and b) extended pyridine ...
Figure 9: Terpyridine-based molecular tweezers with M–salphen arms and their field of application. Figure 9 was adapt...
Figure 10: a) Terpyridine-based molecular tweezers for diphosphate recognition [48]; b) bishelicene chiroptical te...
Figure 11: Terpyridine-based molecular tweezers with allosteric cooperative binding.
Figure 12: Terpyridine-based molecular tweezers presenting closed by default conformation.
Figure 13: Pyridine-pyrimidine-pyridine-based molecular tweezers.
Figure 14: Coordination-responsive molecular tweezers based on nitrogen-containing ligands.
Figure 15: Molecular tweezers exploiting the remote bipyridine or pyridine binding to trigger the conformation...
Figure 16: Bipyridine-based molecular tweezers exploiting the direct s-trans to s-cis-switching for a) anion b...
Figure 17: a) Podand-based molecular tweezers [66,67]. b) Application of tweezers 32 for the catalytic allosteric reg...
Figure 18: Anion-triggered molecular tweezers based on calix[4]pyrrole.
Figure 19: Anion-triggered molecular tweezers.
Figure 20: a) Principle of the weak link approach (WLA) developed by Mirkin and its application to b) symmetri...
Figure 21: Molecular tweezers as allosteric catalyst in asymmetric epoxide opening [80].
Figure 22: Allosteric regulation of catalytic activity in ring-opening polymerization with double tweezers 41.
Figure 23: a) Conformational switching of 42 by intramolecular –S–S– bridge formation. b) Shift of conformatio...
Figure 24: a) Redox-active glycoluril-TTF tweezers 44. b) Mechanism of stepwise oxidation of said tweezers wit...
Figure 25: Mechanism of formation of the mixed-valence dimers of tweezers 45.
Figure 26: Mechanism of carbohydrate liberation upon redox-mediated conformation switching of 46.
Figure 27: a) The encapsulation properties of 47 as well as the DCTNF release process from its host–guest comp...
Figure 28: Redox-active bipyridinium-based tweezers. a) With a ferrocenyl hinge 49, b) with a propyl hinge 50 ...
Figure 29: Redox-active calix[4]arene porphyrin molecular tweezers.
Figure 30: a) Mechanism of the three orthogonal stimuli. b) Cubic scheme showing the eight different states of ...
Figure 31: Redox-controlled molecular gripper based on a diquinone resorcin[4]arene.
Figure 32: a) Shinkai's butterfly tweezers and their different host–guest properties depending on the isomer. ...
Figure 33: Cyclam-tethered tweezers and their different host–guest complexes depending on their configuration.
Figure 34: Azobenzene-based catalytic tweezers.
Figure 35: Photoswitchable PIEZO channel mimic.
Figure 36: Stilbene-based porphyrin tweezers for fullerene recognition.
Figure 37: Stiff-stilbene-based tweezers with urea or thiourea functional units for a) anion binding, b) anion...
Figure 38: Feringa’s photoswitchable organocatalyst (a) and different catalyzed reactions with that system (b)....
Figure 39: a) Irie and Takeshita’s thioindigo-based molecular tweezers. b) Family of hemithioindigo-based mole...
Figure 40: Dithienylethylene crown ether-bearing molecular tweezers reported by Irie and co-workers.
(E,Z)-1,1,1,4,4,4-Hexafluorobut-2-enes: hydrofluoroolefins halogenation/dehydrohalogenation cascade to reach new fluorinated allene
- Nataliia V. Kirij,
- Andrey A. Filatov,
- Yurii L. Yagupolskii,
- Sheng Peng and
- Lee Sprague
Beilstein J. Org. Chem. 2024, 20, 452–459, doi:10.3762/bjoc.20.40
- )-1,1,1,4,4,4-hexafluorobut-2-ene (1a) under UV irradiation leads to the formation of 2,3-dibromo-1,1,1,4,4,4-hexafluorobutane (2) [1]. Subsequent dehydrobromination of compound 2 by treatment with alcoholic potassium hydroxide formed a mixture of isomers 2-bromo-1,1,1,4,4,4-hexafluorobut-2-ene (3a,b) with a
- bromine in the same manner under the influence of ultraviolet irradiation or sunlight with the formation of 2,3-dibromo-1,1,1,4,4,4-hexafluorobutane (2) in 95% yield (Scheme 1). The only difference was that under UV irradiation, the reaction proceeded faster. In both cases, product 2 represented a mixture
- presence of SbCl5, AlCl3, Bu4NOH/MeOH and under UV irradiation. We found that under UV irradiation for several hours, the (E)-isomer 3a completely transformed into (Z)-isomer 3b in quantitative yield (Scheme 3). Next, our attention was directed toward the reaction of (E)- and (Z)-butenes 1a,b with iodine
Graphical Abstract
Scheme 1: Synthesis of 2,3-dibromo-1,1,1,4,4,4-hexafluorobutane (2).
Scheme 2: Synthesis of (E)-butene 3a.
Scheme 3: Isomerization reaction of (E)-butene 3a to (Z)-butene 3b.
Scheme 4: Synthesis of 2-chloro-3-iodo-1,1,1,4,4,4-hexafluorobutane (5).
Scheme 5: Dehydrohalogenation reaction of 2-chloro-3-iodo-1,1,1,4,4,4-hexafluorobutane (5).
Scheme 6: The reaction of silane 8 with I2/KF.
Scheme 7: The reaction of 3a with iPrMgCl and 4-fluorobenzaldehyde (9).
Scheme 8: The reaction of olefin 3a with iPrMgCl.
Scheme 9: The reaction of (E)-butene 3a with BuLi.
Scheme 10: The reaction of allene 11 with bromine.
Scheme 11: The reaction of allene 11 with ICl.
Scheme 12: Synthesis of 2,3-dibromo-2-chloro-1,1,1,4,4,4-hexafluorobutane (16).
Scheme 13: Synthesis of (Z, E)-2-bromo-3-chloro-1,1,1,4,4,4-hexafluorobut-2-enes (17a,b).
Scheme 14: The reaction of olefins 17a,b with BuLi.
Development of a chemical scaffold for inhibiting nonribosomal peptide synthetases in live bacterial cells
- Fumihiro Ishikawa,
- Sho Konno,
- Hideaki Kakeya and
- Genzoh Tanabe
Beilstein J. Org. Chem. 2024, 20, 445–451, doi:10.3762/bjoc.20.39
- derivatives can penetrate cells and interact with A-domains in live bacterial cells, resulting in the competitive inhibition of the labeling by ʟ-Phe-AMS-BPyne. The substituent group (R; gray) of ʟ-Phe-AMS derivatives could facilitate their cell penetration. After UV irradiation (365 nm), the labeled proteins
Graphical Abstract
Figure 1: Biosynthesis of gramicidin S. Modules comprise the PCP, A, E, C, and TE domains. PCP, peptidyl carr...
Figure 2: (A) Adenylation reaction in a nonribosomal peptide synthetase. (B) Structures of aminoacyl-AMS inhi...
Figure 3: Illustration of the inhibition of A-domains by aminoacyl-AMS derivatives in live bacterial cells. C...
Scheme 1: Synthesis of 2′-OH-substituted ʟ-Phe-AMS derivatives. Reagents and conditions: (a) NaH, TBAI, R–X (...
Figure 4: Competitive labeling experiments of GrsA using probe 3 in the presence of ʟ-Phe-AMS inhibitors. (A)...
Green and sustainable approaches for the Friedel–Crafts reaction between aldehydes and indoles
- Periklis X. Kolagkis,
- Eirini M. Galathri and
- Christoforos G. Kokotos
Beilstein J. Org. Chem. 2024, 20, 379–426, doi:10.3762/bjoc.20.36
Graphical Abstract
Scheme 1: Examples of BIMs used for their medicinal properties.
Scheme 2: Mechanisms for the synthesis of BIMs using protic or Lewis acids as catalysts.
Scheme 3: Synthesis of bis(indolyl)methanes using DBDMH.
Scheme 4: Competition experiments and synthesis of bis(indolyl)methanes using DBDMH.
Scheme 5: Proposed mechanism for formation of BIM of using DBDMH.
Scheme 6: Synthesis of bis(indolyl)methanes using I2.
Scheme 7: General reaction mechanism upon halogen bonding.
Scheme 8: Synthesis of bis(indolyl)methanes using I2, introduced by Ji.
Scheme 9: Synthesis of bis(indolyl)methanes using Br2 in CH3CN.
Scheme 10: Βidentate halogen-bond donors.
Scheme 11: Synthesis of bis(indolyl)methanes using bidentate halogen-bond donor 26.
Scheme 12: Proposed reaction mechanism.
Scheme 13: Synthesis of bis(indolyl)methanes using iodoalkyne as catalyst.
Scheme 14: Proposed reaction mechanism.
Scheme 15: Optimized reaction conditions used by Ramshini.
Scheme 16: Activation of the carbonyl group by HPA/TPI-Fe3O4.
Scheme 17: Synthesis of BIMs in the presence of nanoAg-Pt/SiO2-doped silicate.
Scheme 18: Mechanism of action proposed by Khalafi-Nezhad et al.
Scheme 19: Activation of the carbonyl group by the Cu–isatin Schiff base complex.
Scheme 20: Optimum reaction conditions published by Jain.
Scheme 21: Organocatalytic protocol utilizing nanoparticles introduced by Bankar.
Scheme 22: Activation of the carbonyl group by the AlCl3·6H2O-SDS-SiO2 complex.
Scheme 23: Optimal reaction conditions for the aforementioned nano-Fe3O4 based catalysts.
Scheme 24: Nanocatalytic protocol proposed by Kaur et al.
Scheme 25: Microwave approach introduced by Yuan.
Scheme 26: Microwave approach introduced by Zahran et al.
Scheme 27: Microwave irradiation protocol introduced by Bindu.
Scheme 28: Silica-supported microwave irradiation protocol.
Scheme 29: Proposed mechanism for formation of BIM by Nongkhlaw.
Scheme 30: Microwave-assisted synthesis of BIMs catalyzed by succinic acid.
Scheme 31: Proposed mechanism of action of MMO-4.
Scheme 32: Catalytic approach introduced by Muhammadpoor-Baltork et al.
Scheme 33: Reaction conditions used by Xiao-Ming.
Scheme 34: Ultrasonic irradiation-based protocol published by Saeednia.
Scheme 35: Pyruvic acid-mediated synthesis of BIMs proposed by Thopate.
Scheme 36: Synthesis of BIMs using [bmim]BF4 or [bmim]PF6 ionic liquids.
Scheme 37: Synthesis of BIMs utilizing In(OTf)3 in octylmethylimidazolium hexafluorophosphate as ionic liquid.
Scheme 38: FeCl3·6H2O-catalyzed synthesis of BIMs with use of ionic liquid.
Scheme 39: Synthesis of BIMs utilizing the [hmim]HSO4/EtOH catalytic system.
Scheme 40: Synthesis of BIMs utilizing acidic ionic liquid immobilized on silica gel (ILIS-SO2Cl).
Scheme 41: The [bmim][MeSO4]-catalyzed reaction of indole with various aldehydes.
Scheme 42: The role of [bmim][MeSO4] in catalyzing the reaction of indole with aldehydes.
Scheme 43: Synthesis of BIMs utilizing FeCl3-based ionic liquid ([BTBAC]Cl-FeCl3) as catalyst.
Scheme 44: Synthesis of BIMs using [Msim]Cl at room temperature.
Scheme 45: [Et3NH][H2PO4]-catalyzed synthesis of bis(indolyl)methanes.
Scheme 46: PILs-catalyzed synthesis of bis(indolyl)methanes.
Scheme 47: FSILs-mediated synthesis of bis(indolyl)methanes.
Scheme 48: Possible “release and catch” catalytic process.
Scheme 49: Synthesis of bis(indolyl)methanes by [DABCO-H][HSO4].
Scheme 50: Synthesis of bis(indolyl)methanes by [(THA)(SO4)].
Scheme 51: Synthesis of BBSI-Cl and BBSI-HSO4.
Scheme 52: Synthesis of BIMs in the presence of BBSI-Cl and BBSI-HSO4.
Scheme 53: Chemoselectivity of the present method.
Scheme 54: Synthesis of BIMs catalyzed by chitosan-supported ionic liquid.
Scheme 55: Proposed mechanism of action of CSIL.
Scheme 56: Optimization of the reaction in DESs.
Scheme 57: Synthesis of BIMs using ChCl/SnCl2 as DES.
Scheme 58: Synthesis of BIMs derivatives in presence of DES.
Scheme 59: BIMs synthesis in choline chloride/urea (CC/U).
Scheme 60: Flow chemistry-based synthesis of BIMs by Ley.
Scheme 61: Flow chemistry-based synthesis of BIMs proposed by Nam et al.
Scheme 62: Amino-catalyzed reaction of indole with propionaldehyde.
Scheme 63: Aminocatalytic synthesis of BIMs.
Scheme 64: Proposed mechanism for the aminocatalytic synthesis of BIMs.
Scheme 65: Enzymatic reaction of indole with aldehydes.
Scheme 66: Proposed mechanism for the synthesis of BIMs catalyzed by TLIM.
Scheme 67: Proposed reaction mechanism by Badsara.
Scheme 68: Mechanism proposed by D’Auria.
Scheme 69: Photoinduced thiourea catalysis.
Scheme 70: Proposed mechanism of photoacid activation.
Scheme 71: Proposed mechanism of action for CF3SO2Na.
Scheme 72: Proposed mechanism for the synthesis of BIMs by Mandawad.
Scheme 73: Proposed mechanism for the (a) acid generation and (b) synthesis of BIMs.
Scheme 74: a) Reaction conditions employed by Khaksar and b) activation of the carbonyl group by HFIP.
Scheme 75: Activation of the carbonyl group by the PPy@CH2Br through the formation of a halogen bond.
Scheme 76: Reaction conditions utilized by Mhaldar et al.
Scheme 77: a) Reaction conditions employed by López and b) activation of the carbonyl group by thiourea.
Scheme 78: Infrared irradiation approach introduced by Luna-Mora and his research group.
Scheme 79: Synthesis of BIMs with the use of the Fe–Zn BMOF.
Mechanisms for radical reactions initiating from N-hydroxyphthalimide esters
- Carlos R. Azpilcueta-Nicolas and
- Jean-Philip Lumb
Beilstein J. Org. Chem. 2024, 20, 346–378, doi:10.3762/bjoc.20.35
- photosensitizer in an energy-transfer (EnT) mechanism. This proposal was supported by fluorescence quenching measurements, as well as the direct excitation of 44 by UV irradiation, resulting in the formation of 45 in a 45% yield. According to this hypothesis, NHPI ester 44 would adopt a favorable conformation (46
Graphical Abstract
Scheme 1: Comparison between Barton and NHPI ester radical precursors.
Scheme 2: Overview of the mechanisms and activation modes involved in radical generation from RAEs.
Scheme 3: Common mechanisms in photocatalysis.
Scheme 4: A) Giese-type radical addition of NHPI esters mediated by a reductive quenching photocatalytic cycl...
Scheme 5: A) Minisci-type radical addition of NHPI esters. B) Reaction mechanism involving an “off-cycle” red...
Scheme 6: Activation of NHPI esters through hydrogen-bonding in an oxidative quenching photocatalytic cycle.
Scheme 7: SET activation of RAE facilitated by a Lewis acid catalyst.
Scheme 8: PCET activation of NHPI esters in the context of a radical-redox annulation.
Scheme 9: Activation enabled by a strong excited-state reductant catalyst and its application in the dearomat...
Scheme 10: Proposed formation of an intramolecular charge-transfer complex in the synthesis of (spiro)anellate...
Scheme 11: Formation of a charge-transfer complex between enamides and NHPI esters enabled by a chiral phospha...
Scheme 12: Activation of NHPI ester through the formation of photoactive EDA-complexes.
Scheme 13: A) EDA complex-mediated radical hydroalkylation reactions of NHPI esters. B) Proposed mechanism for...
Scheme 14: Proposed radical chain mechanism initiated by EDA-complex formation.
Scheme 15: A) Photoinduced decarboxylative borylation. B) Proposed radical chain mechanism.
Scheme 16: A) Activation of NHPI esters mediated by PPh3/NaI. B) Proposed catalytic cycle involving EDA-comple...
Scheme 17: A) Radical generation facilitated by EDA complex formation between PTH1 catalyst and NHPI esters. B...
Scheme 18: Proposed catalytic cycle for the difunctionalization of styrenes.
Scheme 19: Formation of a charge-transfer complex between NHPI esters and Cs2CO3 enables decarboxylative amina...
Scheme 20: 3-Acetoxyquinuclidine as catalytic donor in the activation of TCNHPI esters.
Scheme 21: A) Photoinduced Cu-catalyzed decarboxylative amination. B) Proposed catalytic cycle. C) Radical clo...
Scheme 22: A) Photoinduced Pd-catalyzed aminoalkylation of 1,4-dienes. B) Proposed catalytic cycle.
Scheme 23: A) TM-catalyzed decarboxylative coupling of NHPI esters and organometallic reagents. B) Representat...
Scheme 24: Synthetic applications of the TM-catalyzed decarboxylative coupling of NHPI esters and organometall...
Scheme 25: A) Ni-catalyzed cross-electrophile coupling of NHPI esters. B) Representative catalytic cycle.
Scheme 26: A) Synthetic applications of decarboxylative cross-electrophile couplings. B) Decarboxylative aryla...
Scheme 27: A) Activation of tetrachlorophthalimide redox-active esters enabled by a low-valency Bi complex. B)...
Scheme 28: Activation of NHPI esters mediated by Zn0 applied in a Z-selective alkenylation reaction.
Scheme 29: A) Activation of NHPI esters enabled by a pyridine-boryl radical species applied to the decarboxyla...
Scheme 30: A) Decarboxylative coupling of RAE and aldehydes enabled by NHC-catalyzed radical relay. B) Propose...
Scheme 31: A) Decarboxylative C(sp3)–heteroatom coupling reaction of NHPI esters under NHC catalysis B) The NH...
Scheme 32: A) Electrochemical Giese-type radical addition of NHPI esters. B) Reaction mechanism.
Scheme 33: Electrochemical Minisci-type radical addition of NHPI-esters.
Scheme 34: Ni-electrocatalytic cross-electrophile coupling of NHPI esters with aryl iodides.
Scheme 35: A) Decarboxylative arylation of NHPI esters under Ag-Ni electrocatalysis B) Formation of AgNP on th...
Scheme 36: Synthetic applications of decarboxylative couplings of NHPI esters under Ni-electrocatalysis.
Scheme 37: Examples of natural product syntheses in which RAEs were used in key C–C bond forming reactions.
Beyond n-dopants for organic semiconductors: use of bibenzo[d]imidazoles in UV-promoted dehalogenation reactions of organic halides
- Kan Tang,
- Megan R. Brown,
- Chad Risko,
- Melissa K. Gish,
- Garry Rumbles,
- Phuc H. Pham,
- Oana R. Luca,
- Stephen Barlow and
- Seth R. Marder
Beilstein J. Org. Chem. 2023, 19, 1912–1922, doi:10.3762/bjoc.19.142
- potentials of the halides that can be reduced in this way, quantum-chemical calculations, and steady-state and transient absorption spectroscopy suggest that UV irradiation accelerates the reactions via cleavage of the dimers to the corresponding radical monomers. Keywords: dehalogenation; n-dopant
- example, see ref. [32]), and were synthesized as described in Supporting Information File 1. More complete data are shown in Supporting Information File 1, Tables S1 and S2. As in the case of 1a, conversions and yields under UV irradiation in the absence of reductant are low on a 2 h timescale (≤10%) and
- the main products are those in which the halide is replaced by a hydrogen atom. The more easily reduced benzyl halides examined (1b and 1c) are dehalogenated by (N-DMBI)2 in the dark, and with (N-DMBI)2 and UV irradiation are quantitatively dehalogenated in 2–6 h with the corresponding substituted
Graphical Abstract
Figure 1: (a, b) Schematics of previous approaches to dehalogenation-based reactions using molecular reductan...
Scheme 1: Selective deiodination of 2-iodobenzyl chloride.
Scheme 2: Reaction mechanisms for the reactions of dimeric reductants (D2) such as (Y-DMBI)2 derivatives with...
Figure 2: (a) A representative temporal evolution of % conversion (blue squares), % toluene yield (red diamon...
Figure 3: Top: UV–vis absorption spectra for the two dimeric reductants in THF emphasizing (a) the different ...
Figure 4: Transient absorption spectra of (a) (N-DMBI)2 in MeCN, (b) (N-DMBI)2 in toluene, and (c) (Cyc-DMBI)2...
Active-metal template clipping synthesis of novel [2]rotaxanes
- Cătălin C. Anghel,
- Teodor A. Cucuiet,
- Niculina D. Hădade and
- Ion Grosu
Beilstein J. Org. Chem. 2023, 19, 1776–1784, doi:10.3762/bjoc.19.130
- and visualized by UV irradiation at 254 nm. Preparative column chromatography was carried out using silica gel 60 (0.040–0.063 mm) from Merck. The NMR spectra were recorded on Bruker Avance 400 MHz or Bruker Avance 600 MHz spectrometers. Chemical shifts (δ) are reported in parts per million (ppm
Graphical Abstract
Figure 1: a. Active-metal template (reported in the literature) and b. active-metal template clipping (used i...
Figure 2: Macrocyclic components of the [2]rotaxanes.
Scheme 1: Synthesis of the key intermediates 6 and 8 and of the reference macrocycle M1.
Scheme 2: Synthesis of [2]rotaxanes R1 and R2.
Figure 3: Top: HRESI(+)-MS spectrum of the rotaxane R1 (left) and R2 (right) [experimental (top) and calculat...
Radical chemistry in polymer science: an overview and recent advances
- Zixiao Wang,
- Feichen Cui,
- Yang Sui and
- Jiajun Yan
Beilstein J. Org. Chem. 2023, 19, 1580–1603, doi:10.3762/bjoc.19.116
- UV irradiation without a photoinitiator [176][177]. Grafted polymers and untethered polymers are generated simultaneously in the presence of a monomer. Ionizing radiation including high-energy photons (X-rays and γ-rays) and charged α- or β-particles generate charged particles, especially electrons
Graphical Abstract
Scheme 1: Oxidation of catechol and subsequent cross-linking. Scheme 1 redrawn from [3].
Scheme 2: (A) Structure of typical urushiol in Chinese lacquer, and (B) schematic process of laccase-catalyze...
Scheme 3: A) Primary amino acid sequence of mfp-1, mfp-3, and mfp-5 (Y: DOPA, K: lysine). B) Scheme showing e...
Scheme 4: Activation–deactivation equilibrium in nitroxide-mediated polymerizations. Bicomponent initiating s...
Scheme 5: Mechanism of a transition metal complex-mediated ATRP. Scheme 5 redrawn from [14].
Scheme 6: Mechanism of RAFT polymerization. Scheme 6 redrawn from [68].
Scheme 7: Degenerative transfer (a) and reversible termination (b) mechanism of OMRP. Scheme 7 redrawn from [70].
Scheme 8: Simplified mechanism of a RITP. Scheme 8 redrawn from [21].
Scheme 9: (A) Structures of π-conjugated conductive polymers. (B) Examples of conductive polymer synthesis vi...
Scheme 10: Possible regiochemical couplings in PATs. Scheme 10 redrawn from [79].
Scheme 11: General thiol-ene photopolymerization process. Scheme 11 redrawn from [81].
Scheme 12: (a) Three generations of Grubbs catalysts. (b) Proposed mechanism for photo-ROMP via a reductive qu...
Scheme 13: Pyrylium and thiopyrylium salts studied by Boydston et al. Scheme 13 redrawn from [91].
Scheme 14: A general illustration of post-polymerization modification by thiol–ene chemistry.
Scheme 15: Introduction of functionalities by nitroxide radical coupling of HO-TEMPO derivatives.
Scheme 16: Chemical reaction process scheme of DCP-induced crosslinking of LDPE. Scheme 16 redrawn from [126].
Scheme 17: A probable mechanism of radical-induced hydrosilylation.
Scheme 18: Polymer surface modification by homolytic dediazonation of diazonium salts.
Scheme 19: Photoinduced polymer surface modification or surface grafting using benzophenone.
Scheme 20: Depolymerization mechanism of common photoresists. (a) A possible mechanism of radiation decomposit...
Scheme 21: Proposed mechanisms of photooxidative depolymerization of polystyrene. (a) Scheme 21a was reprinted with perm...
Exploring the role of halogen bonding in iodonium ylides: insights into unexpected reactivity and reaction control
- Carlee A. Montgomery and
- Graham K. Murphy
Beilstein J. Org. Chem. 2023, 19, 1171–1190, doi:10.3762/bjoc.19.86
Graphical Abstract
Figure 1: Generic representation of halogen bonding.
Figure 2: Quantitative evaluation of σ-holes in monovalent iodine-containing compounds; and, qualitative mole...
Figure 3: Quantitative evaluation of σ-holes in hypervalent iodine-containing molecules; and, qualitative MEP...
Figure 4: Quantitative evaluation of σ-holes in iodonium ylides; and, qualitative MEP map of I-12 from −0.083...
Scheme 1: Outline of possible reaction pathways between iodonium ylides and Lewis basic nucleophiles (top); a...
Scheme 2: Metal-free cyclopropanations of iodonium ylides, either as intermolecular (a) or intramolecular pro...
Figure 5: Zwitterionic mechanism for intramolecular cyclopropanation of iodonium ylides (left); and, stepwise...
Scheme 3: Metal-free intramolecular cyclopropanation of iodonium ylides.
Figure 6: Concerted cycloaddition pathway for the metal-free, intramolecular cyclopropanation of iodonium yli...
Scheme 4: Reaction of ylide 6 with diphenylketene to form lactone 24 and 25.
Figure 7: Nucleophilic (top) and electrophilic (bottom) addition pathways proposed by Koser and Hadjiarapoglo...
Scheme 5: Indoline synthesis from acyclic iodonium ylide 31 and tertiary amines.
Scheme 6: N-Heterocycle synthesis from acyclic iodonium ylide 31 and secondary amines.
Figure 8: Proposed mechanism for the formation of 33a from iodonium ylides and amines, involving an initial h...
Scheme 7: Indoline synthesis from acyclic iodonium ylides 39 and tertiary amines under blue light photocataly...
Scheme 8: Metal-free cycloproponation of iodonium ylides under blue LED irradiation. aUsing trans-β-methylsty...
Figure 9: Proposed mechanism of the cyclopropanation between iodonium ylides and alkenes under blue LED irrad...
Scheme 9: Formal C–H alkylation of iodonium ylides by nucleophilic heterocycles under blue LED irradiation.
Figure 10: Proposed mechanism of the formal C–H insertion of pyrrole under blue LED irradiation.
Scheme 10: X–H insertions between iodonium ylides and carboxylic acids, phenols and thiophenols.
Figure 11: Mechanistic proposal for the X–H insertion reactions of iodonium ylides.
Scheme 11: Radiofluorination of biphenyl using iodonium ylides 54a–e derived from various β-dicarbonyl auxilia...
Scheme 12: Radiofluorination of arenes using spirocycle-derived iodonium ylides 56.
Scheme 13: Radiofluorination of arenes using SPIAd-derived iodonium ylides 58.
Figure 12: Calculated reaction coordinate for the radiofluorination of iodonium ylide 60.
Scheme 14: Radiofluorination of iodonium ylides possessing various ortho- and para-substituents on the iodoare...
Figure 13: Difference in Gibbs activation energy for ortho- or para-anisyl derived iodonium ylides 63a and 63b....
Figure 14: Proposed equilibration of intermediates to transit between 64a (the initial adduct formed between 6...
Scheme 15: Comparison of 31 and ortho-methoxy iodonium ylide 39 in rhodium-catalyzed cyclopropanation and cycl...
Figure 15: X-ray crystal structure of dimeric 39 [6], (CCDC# 893474) [143,144].
Scheme 16: Enaminone synthesis using diazonium and iodonium ylides.
Figure 16: Transition state calculations for enaminone synthesis from iodonium ylides and thioamides.
Scheme 17: The reaction between ylides 73a–f and N-methylpyrrole under 365 nm UV irradiation.
Figure 17: Crystal structures of 76c (top) and 76e (bottom) [101], (CCDC# 2104180 & 2104181) [143,144].
Photoredox catalysis harvesting multiple photon or electrochemical energies
- Mattia Lepori,
- Simon Schmid and
- Joshua P. Barham
Beilstein J. Org. Chem. 2023, 19, 1055–1145, doi:10.3762/bjoc.19.81
Graphical Abstract
Figure 1: Oxidative and reductive activations of organic compounds harvesting photoredox catalysis.
Figure 2: General catalytic cycles of radical ion conPET (left) and radical ion e-PRC (right).
Figure 3: “Beginner’s guide”: comparison between advantages, capacities, and prospectives of conPET and PEC.
Figure 4: A) conPET reductive dehalogenation of aryl halides with PDI. B) Reductive C–H arylation with pyrrol...
Figure 5: A) Chromoselective mono- and disubstitution or polybrominated pyrimidines with pyrroles. B) Sequent...
Figure 6: A) Synthesis of pyrrolo[1,2-a]quinolines. B) Synthesis of ullazines.
Figure 7: A) Reductive phosphorylation of aryl halides via conPET. B) Selected examples from the substrate sc...
Figure 8: A) Reductive dehalogenation of aryl halides via conPET and selected examples from the substrate sco...
Figure 9: A) Reductive C–H arylation of aryl halides via conPET (top) and selected examples from the substrat...
Figure 10: A) Reductive hydrodehalogenation of aryl halides with Mes-Acr-BF4. B) Selected examples from the su...
Figure 11: A) Reductive hydrodechlorination of aryl chlorides with 4-DPAIPN. B) Proposed formation of CO2•−. C...
Figure 12: A) Reductive conPET borylation with 3CzEPAIPN (top) and selected examples from the substrate scope ...
Figure 13: Scale-up of conPET phosphorylation with 3CzEPAIPN.
Figure 14: A) Borylation of 1d. B) Characteristics and structure of PC1 with green and red parts showing the l...
Figure 15: A) Reductive C–H arylation scope with polysulfide conPET (top) and selected examples from the subst...
Figure 16: Scale-up of A) C–H arylation and B) dehaloborylation with polysulfide photocatalysis in continuous-...
Figure 17: A) Formation of [Ir1]0 and [Ir2]0 upon PET between [Ir1]+ and Et3N. B) Mechanism of multi-photon ta...
Figure 18: A) Reductive hydrodehalogenation of aryl halides via multi-photon tandem photocatalysis. B) Selecte...
Figure 19: A) Carbonylative amidation of aryl halides in continuous flow. B) Selected examples from the substr...
Figure 20: A) General scheme for reductive (RQ) and oxidative quenching (OQ) protocols using [FeIII(btz)3](PF6)...
Figure 21: A) Carbonylative amidation of alkyl iodides with [IrIII(ppy)2(dtbbpy)]PF6. B) Selected examples fro...
Figure 22: A) Carboxylative C–N bond cleavage in cyclic amines. B) Selected examples from the substrate scope....
Figure 23: A) Formal reduction of alkenes to alkanes via transfer hydrogenation. B) Selected examples from the...
Figure 24: A) Birch-type reduction of benzenes with PMP-BPI. B) Selected examples from the substrate scope (sc...
Figure 25: Proposed mechanism of the OH− mediated conPET Birch-type reduction of benzene via generation of sol...
Figure 26: Reductive detosylation of N-tosylated amides with Mes-Acr-BF4. B) Selected examples from the substr...
Figure 27: A) Reductive detosylation of N-tosyl amides by dual PRC. B) Selected examples from the substrate sc...
Figure 28: A) Mechanism of the dual PRC based on PET between [Cu(dap)2]+ and DCA. B) Mechanism of the dual PRC...
Figure 29: A) N–O bond cleavage in Weinreb amides with anthracene. B) N–O bond cleavage in Weinreb amides rely...
Figure 30: A) Pentafluorosulfanylation and fluoride elimination. B) Mechanism of the pentafluorosulfanylation ...
Figure 31: A) α-Alkoxypentafluorosulfanylation (top) and selected examples from the substrate scope (bottom). ...
Figure 32: A) Oxidative amination of arenes with azoles catalyzed by N-Ph PTZ. B) Selected examples from the s...
Figure 33: A) C(sp3)–H bond activation by HAT via chloride oxidation by *N-Ph PTZ•+. B) Proposed mechanism for...
Figure 34: A) Recycling e-PRC C–H azolation of electron-rich arenes with pyrazoles using Mes-Acr+ as a photoca...
Figure 35: A) Radical ion e-PRC direct oxidation of unactivated arenes using TAC+ as an electro-activated phot...
Figure 36: A) Radical ion e-PRC direct oxidation of unactivated arenes using TPA as an electro-activated photo...
Figure 37: Proposed mechanism (top) and mode of preassembly (bottom).
Figure 38: A) Possible preassemblies of reactive (left) vs unreactive (right) arenes. B) Calculated spin densi...
Figure 39: A) Recycling e-PRC C(sp2 )–H acetoxylation of arenes using DDQ as a photocatalyst. B) Proposed cata...
Figure 40: Gram scale hydroxylation of benzene in a recirculated flow setup.
Figure 41: A) Radical ion e-PRC vicinal diamination of alkylarenes using TAC+ as an electro-activated photocat...
Figure 42: A) Sequential oxygenation of multiple adjacent C–H bonds under radical ion e-PRC using TAC+ as an e...
Figure 43: A) Enantioselective recycling e-PRC cyanation of benzylic C–H bonds using ADQS as photocatalyst. B)...
Figure 44: Proposed tandem mechanism by Xu and co-workers.
Figure 45: A) Enantioselective recycling e-PRC decarboxylative cyanation using Cu(acac)2, Ce(OTf)3 and a box l...
Figure 46: A) Enantioselective recycling e-PRC benzylic cyanation using Cu(MeCN)4BF4, box ligand and anthraqui...
Figure 47: A) Radical ion e-PRC acetoxyhydroxylation of aryl olefins using TAC+ as an electro-activated photoc...
Figure 48: Selected examples from the substrate scope.
Figure 49: Photoelectrochemical acetoxyhydroxylation in a recirculated flow setup.
Figure 50: A) Radical ion e-PRC aminooxygenation of aryl olefins using TAC+ as an electro-activated photocatal...
Figure 51: A) Recycling e-PRC C–H alkylation of heteroarenes with organic trifluoroborates using Mes-Acr+ as p...
Figure 52: A) Recycling e-PRC decarboxylative C–H alkylation of heteroarenes using CeCl3·7H2O as catalyst. B) ...
Figure 53: A) Recycling e-PRC decarboxylative C–H alkylation of heteroarenes using Fe(NH4)2(SO4)2·6H2O as cata...
Figure 54: A) Recycling e-PRC C–H alkylation of heteroarenes with alkyl oxalates and 4CzIPN as photocatalyst. ...
Figure 55: A) Recycling e-PRC decarboxylative C–H carbamoylation of heteroarenes using 4CzIPN as photocatalyst...
Figure 56: A) Photoelectrochemical HAT-mediated hydrocarbon activation via the chlorine radical. B) Proposed m...
Figure 57: A) Selected examples from the substrate scope. B) Gram and decagram scale semi-continuous flow PEC ...
Figure 58: A) Photoelectrochemical HAT-mediated dehydrogenative coupling of benzothiazoles with aliphatic C–H ...
Figure 59: A) Photoelectrochemical HAT activation of ethers using electro-activated TAC+ as photocatalyst. B) ...
Figure 60: Selected examples from the substrate scope.
Figure 61: A) Photoelectrochemical HAT-mediated synthesis of alkylated benzimidazo-fused isoquinolinones using...
Figure 62: A) Decoupled photoelectrochemical cerium-catalyzed oxydichlorination of alkynes using CeCl3 as cata...
Figure 63: Proposed decoupled photoelectrochemical mechanism.
Figure 64: A) Decoupled photoelectrochemical ring-opening bromination of tertiary cycloalkanols using MgBr2 as...
Figure 65: A) Recycling e-PRC ring-opening functionalization of cycloalkanols using CeCl3 as catalyst. B) Prop...
Figure 66: Selected examples from the substrate scope of the PEC ring-opening functionalization.
Figure 67: A) Radical ion e-PRC reduction of chloro- and bromoarenes using DCA as catalyst and various accepto...
Figure 68: A) Screening of different phthalimide derivatives as catalyst for the e-PRC reduction of aryl halid...
Figure 69: Screening of different organic catalysts for the e-PRC reduction of trialkylanilium salts.
Figure 70: A) e-PRC reduction of phosphonated phenols and anilinium salts. B) Selected examples from the subst...
Figure 71: A) ConPET and e-PRC reduction of 4-bromobenzonitrile using a naphthalene diimide (NDI) precatalyst ...
Figure 72: A) Radical ion e-PRC reduction of phosphinated aliphatic alcohols with n-BuO-NpMI as catalyst. B) C...
Figure 73: Selected examples from the substrate scope.
Figure 74: A) Recycling e-PRC reductive dimerization of benzylic chlorides using a [Cu2] catalyst. B) Proposed...
Figure 75: A) Decoupled photoelectrochemical C–H alkylation of heteroarenes through deamination of Katritzky s...
Figure 76: Proposed mechanism by Chen and co-workers.
Synthesis of substituted 8H-benzo[h]pyrano[2,3-f]quinazolin-8-ones via photochemical 6π-electrocyclization of pyrimidines containing an allomaltol fragment
- Constantine V. Milyutin,
- Andrey N. Komogortsev,
- Boris V. Lichitsky,
- Mikhail E. Minyaev and
- Valeriya G. Melekhina
Beilstein J. Org. Chem. 2023, 19, 778–788, doi:10.3762/bjoc.19.58
- two directions resulting in the formation of a mixture of the corresponding dihydrobenzo[h]pyrano[2,3-f]quinazolines and polyaromatic products. The obtained dihydro derivatives are stable compounds and do not undergo aromatization upon further UV irradiation. The structures of two of the dihydrobenzo
- ]. Among them, photoreactions of compounds containing the 3-hydroxypyran-4-one (allomaltol) fragment attract considerable attention due to the unique photochemical properties of compounds of this class. Previously it was shown that allomaltol derivatives under UV irradiation undergo contraction of the
- investigated. It should be noted that we have previously studied the photochemical properties of various terarylenes with a 3-hydroxy-4-pyranone moiety [21][22][23][24][25]. It was shown that UV irradiation of such systems leads to a complex mixture of products, apparently due to the simultaneous occurrence of
Graphical Abstract
Scheme 1: Photochemical behavior of terarylenes containing an allomaltol fragment.
Scheme 2: Synthesis of starting compounds 9. Reaction conditions: 13 (1 mmol), NH2CN (14, 3 mmol, 0.13 g), Et...
Scheme 3: Proposed mechanism for the formation of compounds 9.
Scheme 4: Synthesis of methylated derivatives 10. Reaction conditions: 9 (1 mmol), MeI (3 mmol, 0.43 g), K2CO3...
Figure 1: 1H NMR monitoring of the photoreaction of compound 10a under UV irradiation (365 nm) in DMSO-d6 sol...
Figure 2: The crystal structure of compound 11a (one of two polymorph modifications; p = 50%), CCDC 2248033.
Scheme 5: Photochemical synthesis of compounds 11 and 12.
Scheme 6: Proposed mechanism for the studied photoreaction.
Scheme 7: Synthesis of compounds 11g–j starting from pyrimidines 9. Reaction conditions: 9 (0.5 mmol), DMF (1...
Figure 3: One of crystallographically unique molecules of 11g (p = 50%), CCDC 2248035.
Scheme 8: Synthesis of photoproducts 12. Reaction conditions: method A) 10 (0.5 mmol), DMF (15 mL) irradiatio...
pH-Responsive fluorescent supramolecular nanoparticles based on tetraphenylethylene-labelled chitosan and a six-fold carboxylated tribenzotriquinacene
- Nan Yang,
- Yi-Yan Zhu,
- Wei-Xiu Lin,
- Yi-Long Lu and
- Wen-Rong Xu
Beilstein J. Org. Chem. 2023, 19, 635–645, doi:10.3762/bjoc.19.45
- powders of CS-TPE exhibit a pale-yellow appearance under normal daylight conditions and emit intense green-blue light when exposed to UV irradiation (365 nm). This phenomenon differs greatly from the fluorescence properties of conventional ACQ fluorophores, which are typically nonfluorescent under UV
- spectra of TBTQ-C6/CS-TPE with different Rf in aqueous solutions at pH 5.3 and 10.4. Inset: the fluorescent images of the corresponding measured solutions taken under UV irradiation. ([TBTQ-C6] = 0.10 mM, [CS-TPE-2%] = 32 μg/mL), [CS-TPE-10%] = 34 μg/mL, [CS-TPE-20%] = 35 μg/mL, [TBTQ-C6/CS-TPE-2%] = 48
Graphical Abstract
Scheme 1: (a) Synthesis route to CS-TPE. (b) Structure of TBTQ-C6. (c) Construction of TBTQ-C6/CS-TPE supramo...
Figure 1: Partial 1H NMR spectra (400 MHz, CD3COOD/D2O, 25 °C) of (a) CS, (b) CS-TPE-2%, (c) CS-TPE-10%, and ...
Figure 2: (a) Optical images of CS-TPE under daylight (top) and 365 nm UV light (bottom) in the solid state; ...
Figure 3: TEM images of (a) CS-TPE-2%, (b) CS-TPE-10%, and (c) CS-TPE-20% assemblies at pH 5.3; TEM images of...
Figure 4: (a, c, e) Optical transmittance and (b, d, f) transmittance as a function of [TBTQ-C6] at 293 nm of...
Figure 5: (a, c, e) Optical transmittance and (b, d, f) CS-TPE concentration-dependent optical transmittance ...
Figure 6: TEM images of (a) TBTQ-C6/CS-TPE-10% in aqueous solution at pH 5.3, (b) after adjustment of the sol...
Figure 7: (a) Fluorescence spectra of CS-TPE with different Rf in aqueous solutions at pH 5.3 and 10.4; (b) f...
Access to cyclopropanes with geminal trifluoromethyl and difluoromethylphosphonate groups
- Ita Hajdin,
- Romana Pajkert,
- Mira Keßler,
- Jianlin Han,
- Haibo Mei and
- Gerd-Volker Röschenthaler
Beilstein J. Org. Chem. 2023, 19, 541–549, doi:10.3762/bjoc.19.39
- % yield (Table 1, entry 6). In addition, in a catalyst-free reaction under UV irradiation, no reaction occurred and the starting diazo compound 5 was recovered (Table 1, entry 7). Having identified the optimal catalyst and conditions, we then examined the scope of the cyclopropanation reaction by reacting
Graphical Abstract
Scheme 1: Previous works (A–D) and the extension (this work).
Scheme 2: Synthesis of diethyl 2-diazo-1,1,3,3,3-pentafluoropropylphosphonate (5).
Scheme 3: Scope of the cyclopropanation. Reaction conditions: alkene (0.15 mmol), diazo compound 5 (0.1 mmol)...
Figure 1: 19F,1H-HOESY spectrum of compound 6c.
Scheme 4: Scope of the cyclopropanation. Reaction conditions: alkene (0.15 mmol), diazo compound 5 (0.1 mmol)...
Scheme 5: Addition of CuI to the diazo compound 5.
Scheme 6: Possible addition of styrene to Int2 yielding Int4_1 and Int4_2 through Int3_1 and Int3_2.
Scheme 7: Possible addition of styrene to Int2 yielding Int4_3 and Int4_4 without further intermediates.
Scheme 8: Formation of the products Pr1 to Pr4.
Strategies to access the [5-8] bicyclic core encountered in the sesquiterpene, diterpene and sesterterpene series
- Cécile Alleman,
- Charlène Gadais,
- Laurent Legentil and
- François-Hugues Porée
Beilstein J. Org. Chem. 2023, 19, 245–281, doi:10.3762/bjoc.19.23
- ). Interestingly, the reaction was carried out under UV irradiation and in the presence of catalytic nickel diiodide allowing formation of the expected compound in 63% yield [67]. 4.2 SmI2-mediated ketyl addition: discussion around pleuromutilin scaffold access Despite the promising results of the SmI2-mediated
Graphical Abstract
Figure 1: Examples of terpenes containing a bicyclo[3.6.0]undecane motif.
Figure 2: Commercially available first and second generation Grubbs and Hoveyda–Grubbs catalysts.
Figure 3: Examples of strategies to access the fusicoccan and ophiobolin tricyclic core structure by RCM.
Scheme 1: Synthesis of bicyclic core structure 12 of ophiobolin M (13) and cycloaraneosene (14).
Scheme 2: Synthesis of the core structure 21 of ophiobolins and fusicoccanes.
Scheme 3: Ring-closing metathesis attempts starting from thioester 22.
Scheme 4: Total synthesis of ent-fusicoauritone (28).
Figure 4: General structure of ophiobolins and congeners.
Scheme 5: Total synthesis of (+)-ophiobolin A (8).
Scheme 6: Investigation of RCM for the synthesis of ophiobolin A (8). Path A) RCM with TBDPS-protected alcoho...
Scheme 7: Synthesis of the core structure of cotylenin A aglycon, cotylenol (50).
Scheme 8: Synthesis of tricyclic core structure of fusicoccans.
Scheme 9: Total synthesis of (−)-teubrevin G (59).
Scheme 10: Synthesis of the core skeleton 63 of the basmane family.
Scheme 11: Total synthesis of (±)-schindilactone A (68).
Scheme 12: Total synthesis of dactylol (72).
Scheme 13: Ring-closing metathesis for the total synthesis of (±)-asteriscanolide (2).
Scheme 14: Synthesis of the simplified skeleton of pleuromutilin (1).
Scheme 15: Total synthesis of (−)-nitidasin (93) using a ring-closing metathesis to construct the eight-member...
Scheme 16: Total synthesis of (±)-naupliolide (97).
Scheme 17: Synthesis of the A-B ring structure of fusicoccane (101).
Scheme 18: First attempts of TRCM of dienyne substrates.
Scheme 19: TRCM on optimized substrates towards the synthesis of ophiobolin A (8).
Scheme 20: Tandem ring-closing metathesis for the synthesis of variecolin intermediates 114 and 115.
Scheme 21: Synthesis of poitediol (118) using the allylsilane ring-closing metathesis.
Scheme 22: Access to scaffold 122 by a NHK coupling reaction.
Scheme 23: Key step to construct the [5-8] bicyclooctanone core of aquatolide (4).
Scheme 24: Initial strategy to access aquatolide (4).
Scheme 25: Synthetic plan to cotylenin A (130).
Scheme 26: [5-8] Bicyclic structure of brachialactone (7) constructed by a Mizoroki–Heck reaction.
Scheme 27: Influence of the replacement of the allylic alcohol moiety.
Scheme 28: Formation of variecolin intermediate 140 through a SmI2-mediated Barbier-type reaction.
Scheme 29: SmI2-mediated ketyl addition. Pleuromutilin (1) eight-membered ring closure via C5–C14 bond formati...
Scheme 30: SmI2-mediated dialdehyde cyclization cascade of [5-8-6] pleuromutilin scaffold 149.
Scheme 31: A) Modular synthetic route to mutilin and pleuromutilin family members by Herzon’s group. B) Scaffo...
Scheme 32: Photocatalyzed oxidative ring expansion in pleuromutilin (1) total synthesis.
Scheme 33: Reductive radical cascade cyclization route towards (−)-6-epi-ophiobolin N (168).
Scheme 34: Reductive radical cascade cyclization route towards (+)-6-epi-ophiobolin A (173).
Scheme 35: Radical 8-endo-trig-cyclization of a xanthate precursor.
Figure 5: Structural representations of hypoestin A (177), albolic acid (178), and ceroplastol II (179) beari...
Scheme 36: Synthesis of the common [5-8-5] tricyclic intermediate of hypoestin A (177), albolic acid (178), an...
Scheme 37: Asymmetric synthesis of hypoestin A (177), albolic acid (178), and ceroplastol II (179).
Figure 6: Scope of the Pauson–Khand reaction.
Scheme 38: Nazarov cyclization revealing the fusicoauritone core structure 192.
Scheme 39: Synthesis of fusicoauritone (28) through Nazarov cyclization.
Scheme 40: (+)-Epoxydictymene (5) synthesis through a Nicholas cyclization followed by a Pauson–Khand reaction...
Scheme 41: Synthesis of aquatolide (4) by a Mukaiyama-type aldolisation.
Scheme 42: Tandem Wolff/Cope rearrangement furnishing the A-B bicyclic moiety 204 of variecolin.
Scheme 43: Asymmetric synthesis of the A-B bicyclic core 205 and 206 of variecolin.
Scheme 44: Formation of [5-8]-fused rings by cyclization under thermal activation.
Scheme 45: Construction of the [5-8-6] tricyclic core structure of variecolin (3) by Diels–Alder reaction.
Scheme 46: Synthesis of the [6-4-8-5]-tetracyclic skeleton by palladium-mediated cyclization.
Scheme 47: Access to the [5-8] bicyclic core structure of asteriscanolide (227) through rhodium-catalyzed cycl...
Scheme 48: Total syntheses of asterisca-3(15),6-diene (230) and asteriscanolide (2) with a Rh-catalyzed cycliz...
Scheme 49: Photocyclization of 2-pyridones to access the [5-8-5] backbone of fusicoccanes.
Scheme 50: Total synthesis of (+)-asteriscunolide D (245) and (+)-aquatolide (4) through photocyclization.
Scheme 51: Biocatalysis pathway to construct the [5-8-5] tricyclic scaffold of brassicicenes.
Scheme 52: Influence of the CotB2 mutant over the cyclization’s outcome of GGDP.
Combining the best of both worlds: radical-based divergent total synthesis
- Kyriaki Gennaiou,
- Antonios Kelesidis,
- Maria Kourgiantaki and
- Alexandros L. Zografos
Beilstein J. Org. Chem. 2023, 19, 1–26, doi:10.3762/bjoc.19.1
- substantial decrease of the product yield. FGI, followed by methylenation provided the common scaffold 88. Further elaboration of 88 to natural products 90 and 89 was accomplished by UV irradiation at 365 nm in MeOH and by utilizing singlet oxygen (using rose Bengal) in MeCN/pyridine, 40:1, respectively
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).
A Streptomyces P450 enzyme dimerizes isoflavones from plants
- Run-Zhou Liu,
- Shanchong Chen and
- Lihan Zhang
Beilstein J. Org. Chem. 2022, 18, 1107–1115, doi:10.3762/bjoc.18.113
- host against oxidative radicals generated by UV irradiation [25][32]. To verify the antioxidative effect of the isoflavone dimers, 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS)-based antioxidant activity was performed [33]. The results showed that while 2 and 3 had an activity roughly
Graphical Abstract
Figure 1: Structures of cattleyaisoflavones A (1), B (2), C (3), and daidzein (4).
Figure 2: a) The culture in ISP-2 liquid did not produce 1–3, while feeding with 4 restored the production (a...
Figure 3: CYP158C1 dimerizes 4 to form dimers 2 and 5 in vitro (analytical method B, 254 nm). Control conditi...
Scheme 1: a) Compatible and b) incompatible substrates of CYP158C1. Products were identified using analytical...
Scheme 2: Proposed mechanism of CYP158C1-mediated dimerization of isoflavones.
