Interaction of a pyrene derivative with cationic [60]fullerene in phospholipid membranes and its effects on photodynamic actions

• Hayato Takagi,
• Çetin Çelik,
• Ryosuke Fukuda,
• Qi Guo,
• Tomohiro Higashino,
• Hiroshi Imahori,
• Yoko Yamakoshi and
• Tatsuya Murakami

Beilstein J. Org. Chem. 2024, 20, 2732–2738, doi:10.3762/bjoc.20.231

• Instutite for Liberal Arts and Sciences (ILAS), Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan 10.3762/bjoc.20.231 Abstract We have reported that upon visible light irradiation, ferrocene-porphyrin-[60]fullerene triad molecules yield long-lived charge-separated states, enabling the control of the plasma

• light irradiation [7], with the C60 species becoming negatively charged while the ferrocene moiety became positively charged (Figure 1a). This charge-separated state can be used to initiate nanoscale electric fields, e.g., Vm. The design of the triad molecules may also help to keep their orientation

Synthesis of spiroindolenines through a one-pot multistep process mediated by visible light

• Francesco Gambuti,
• Jacopo Pizzorno,
• Chiara Lambruschini,
• Renata Riva and
• Lisa Moni

Beilstein J. Org. Chem. 2024, 20, 2722–2731, doi:10.3762/bjoc.20.230

• materials (Scheme 1d). The synthetic procedure is achieved using blue light irradiation and bromotrichloromethane (BrCCl3), as a one-pot procedure, minimizing chemical wastes, avoiding purification of intermediates, and simplifying practical aspects. Results and Discussion We have recently published the one

• isocyanide without the presence of a catalyst. In order to establish the role of GO we carried out the 3C Ugi-type reaction starting from iminium ion 1a, freshly prepared by visible light irradiation in the presence of bromochloroform [28]. This protocol resulted quite convenient as can be conducted under

• and the intermediates involved, the relationship between the product conversions and the reaction time was investigated in the reaction between N-Ph-THIQ, 3,5-dimethoxyaniline and t-BuNC in the presence of BrCCl3 under light irradiation (Figure 2). This time profile shows that, as soon as the N-Ph

Transition-metal-free synthesis of arylboronates via thermal generation of aryl radicals from triarylbismuthines in air

• Yuki Yamamoto,
• Yuki Konakazawa,
• Kohsuke Fujiwara and
• Akiya Ogawa

Beilstein J. Org. Chem. 2024, 20, 2577–2584, doi:10.3762/bjoc.20.216

• of photocatalysts or UV light irradiation without metal catalysts [45][46][47][48]. Similar homolysis by electrolysis has also been reported [49]. These two activation methods required special equipment (i.e., light sources or electronic devices). To achieve thermal homolysis of the Ar–Bi bonds, the

• reaction conditions were harsh, requiring heating at 260 °C for several days [50]. Thus, only two examples of the use of triarylbismuthines as aryl radical sources have been reported for the synthesis of arylboronates, which proceeds under light irradiation conditions (Scheme 1a) [47][48]. Our group has

A review of recent advances in electrochemical and photoelectrochemical late-stage functionalization classified by anodic oxidation, cathodic reduction, and paired electrolysis

• Nian Li,
• Ruzal Sitdikov,
• Ajit Prabhakar Kale,
• Joost Steverlynck,
• Bo Li and
• Magnus Rueping

Beilstein J. Org. Chem. 2024, 20, 2500–2566, doi:10.3762/bjoc.20.214

• constant voltage (CV) conditions and light irradiation under a nitrogen atmosphere. This method demonstrates broad compatibility with various functional groups and complex substrates, including alcohol, carboxylic acid, esters, alkyl chloride, and tosylate groups. Notably, the LSF of compounds such as

Visible-light-mediated flow protocol for Achmatowicz rearrangement

• Joachyutharayalu Oja,
• Sanjeev Kumar and
• Srihari Pabbaraja

Beilstein J. Org. Chem. 2024, 20, 2493–2499, doi:10.3762/bjoc.20.213

• -off experiment was performed to examine the Achmatowicz rearrangement's dependence on light, and it was observed that continuous light irradiation was required (Table 1, entry 2). Next, we considered running the process without utilizing the Ru(bpy)3Cl2·6H2O catalyst (Table 1, entry 3). There was no

Photoredox-catalyzed intramolecular nucleophilic amidation of alkenes with β-lactams

• Valentina Giraldi,
• Giandomenico Magagnano,
• Daria Giacomini,
• Pier Giorgio Cozzi and
• Andrea Gualandi

Beilstein J. Org. Chem. 2024, 20, 2461–2468, doi:10.3762/bjoc.20.210

• as final product, characterized by significant ring strain [59]. Under light irradiation, PhSSPh is in equilibrium with the corresponding thiyl radical, which is subsequently reduced to thiophenolate by PC•, originating from the reduction of *PC+. The reduction potential of PhS−/PhS• (Epred = +0.45 V

Efficacy of radical reactions of isocyanides with heteroatom radicals in organic synthesis

• Akiya Ogawa and
• Yuki Yamamoto

Beilstein J. Org. Chem. 2024, 20, 2114–2128, doi:10.3762/bjoc.20.182

• , when using sunlight, which is an inexhaustible natural energy, it is expected to be the most environmentally friendly method. The homolysis of E–E upon visible light irradiation is induced by exciting one electron of the isolated electron pair on E to the anti-bonding orbital of the E–E-bond (σ

• not proceed at all for normal isocyanides, but for aromatic isocyanides with electron-withdrawing groups (EWG) such as p-NO2, p-CF3, p-CN, p-Cl, and m-MeO, the desired thiotelluration reaction proceeded under visible light irradiation to successfully afford the corresponding thiotelluration products 4

• ][65][66]. The iodoperfluoroalkylation with radical cyclization of ortho-diisocyanoarenes proceeded efficiently by using AIBN as initiator or using a hexabutyldistannane under visible light irradiation to afford the quinoxaline derivative 25 in good yields (Scheme 18a) [63]. At the same time, a similar

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

• mechanisms of structural changes using in-situ light irradiation with rapid, time-resolved data collection. However, X-ray irradiation has been shown previously to induce Z-to-E isomerisation of Azo-PS, which can lead to inaccuracies in the measured photostationary state. Here, we investigate the effect of

• light and X-ray irradiation on micelles formed from two different PS, containing either an Azo or AAP photoswitch using SAXS with in-situ light irradiation. The effect of X-ray irradiation on the Z isomer is shown to depend on the photoswitch, solvent, concentration and morphology. We use this to create

• brilliance of synchrotron X-ray sources enables the mechanisms of structural changes in PS to be studied, using in-situ light irradiation with time-resolved data collection. For example, Tribet and co-workers used this approach to explore the kinetics of micellisation and dissolution of cationic Azo-PS, both

Harnessing the versatility of hydrazones through electrosynthetic oxidative transformations

• Aurélie Claraz

Beilstein J. Org. Chem. 2024, 20, 1988–2004, doi:10.3762/bjoc.20.175

• photocatalyst TAC+. The electrolysis was carried out at a constant cell potential of 1.5 V under white light irradiation. The carbonyl compound 144 was initially treated with tert-butyl carbazate (145) in acetonitrile in the presence of molecular sieves, followed by the addition of trifluoroacetic acid (TFA) to

Development of a flow photochemical process for a π-Lewis acidic metal-catalyzed cyclization/radical addition sequence: in situ-generated 2-benzopyrylium as photoredox catalyst and reactive intermediate

• Masahiro Terada,
• Zen Iwasaki,
• Ryohei Yazaki,
• Shigenobu Umemiya and
• Jun Kikuchi

Beilstein J. Org. Chem. 2024, 20, 1973–1980, doi:10.3762/bjoc.20.173

• continues to flow and the reaction can be quenched immediately when necessary, the decomposition of an unstable product under the reaction conditions can be avoided [22][23][24][25]. Furthermore, when a photoreaction is performed in a flow system, there is an advantage that the light irradiation efficiency

• intramolecular cyclization followed by proto-demetalation with trifluoroacetic acid (TFA). In catalytic cycle II, photoexcitation of the generated 2-benzopyrylium intermediates A under light irradiation facilitates single-electron transfer (SET) from benzyltrimethylsilane derivatives 2 as the donor molecule

• feature of this sequential transformation is that the in situ-generated 2-benzopyrylium intermediates A are used not only as an electrophile but also as a photoredox catalyst. However, as this reaction is carried out under relatively harsh conditions (i.e., light irradiation, use of an excess amount of

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

• ]. However, under light irradiation, conversion and product yield were higher, although the ratio of diastereomers produced in both cases was almost the same for the E- and Z-isomer, respectively, and did not depend on irradiation. The reaction of 1,2-difluoroethylene with PCl3 and O2 was described by Boyce

Negishi-coupling-enabled synthesis of α-heteroaryl-α-amino acid building blocks for DNA-encoded chemical library applications

• Matteo Gasparetto,
• Balázs Fődi and
• Gellért Sipos

Beilstein J. Org. Chem. 2024, 20, 1922–1932, doi:10.3762/bjoc.20.168

• Negishi reaction (Supporting Information File 1). Preliminary experiments were carried out with and without blue light irradiation in the PhotoCubeTM photoreactor [45]. These experiments revealed that while the conversion of imidazoles and pyrazoles benefits from irradiation, thiazoles seem to be largely

• the blue region. This complex then accelerates the oxidative addition of the aryl halide to the metal, which is usually the rate-limiting step for palladium-catalyzed cross-couplings. Based on these results we decided to perform all Negishi reactions under blue light irradiation. With the optimized

• acetate 2i in high yield. A similar result was obtained for the furanyl derivative 2j. Pyrazoles were the only substrate class which clearly benefited from light irradiation (2k–o), displaying not just a shorter reaction time but also higher yields. Even unprotected pyrazoles (2k, 2m, 2n) performed well

Ring opening of photogenerated azetidinols as a strategy for the synthesis of aminodioxolanes

• Henning Maag,
• Daniel J. Lemcke and
• Johannes M. Wahl

Beilstein J. Org. Chem. 2024, 20, 1671–1676, doi:10.3762/bjoc.20.148

• strategy is founded on the build and release of molecular strain and achieves a formal transposition of a methyl group. During light irradiation, 3-phenylazetidinols are forged as reaction intermediates, which readily undergo ring opening upon the addition of electron-deficient ketones or boronic acids

Supramolecular assemblies of amphiphilic donor–acceptor Stenhouse adducts as macroscopic soft scaffolds

• Ka-Lung Hung,
• Leong-Hung Cheung,
• Yikun Ren,
• Ming-Hin Chau,
• Yan-Yi Lam,
• Takashi Kajitani and
• Franco King-Chi Leung

Beilstein J. Org. Chem. 2024, 20, 1590–1603, doi:10.3762/bjoc.20.142

• revealed by X-ray diffraction analysis. Upon visible-light irradiation, significant transformations of the DA geometry enabled transformations of the supramolecular assemblies on a microscopic scale, subsequently disassembling macroscopic soft scaffolds of DAs. The current work shows promising use for the

• systematically by visible light irradiation. On a macroscopic length scale, the soft DAn scaffolds were able to perform macroscopic structure disassembly upon visible-light irradiation. The biocompatibility of the macroscopic soft DAn scaffolds was investigated, revealing limited cytotoxicity. The current work

• (Figure 1a). Upon 625 nm red-light irradiation for 60 s at 20 °C to reach the photostationary state (PSS), the strong absorption band at 470–685 nm was diminished, with a clear isosbestic point at 259 nm (Figure 1a, red line), which indicates a selective photoisomerization process from the open-isomer O

Benzylic C(sp³)–H fluorination

• Alexander P. Atkins,
• Alice C. Dean and
• Alastair J. J. Lennox

Beilstein J. Org. Chem. 2024, 20, 1527–1547, doi:10.3762/bjoc.20.137

• pioneering report in 2013 that used photocatalyst 9-fluorenone under visible-light irradiation to generate a photoexcited aryl ketone, capable of HAT to promote benzylic fluorination with Selectfluor (Figure 23) [69]. The reaction tolerated an exceptional range of functional groups and enabled the

• showed that 1,2,4,5-tetracyanobenzene could be used under ultraviolet light irradiation as a photocatalyst in the fluorination of benzylic C(sp3)–H bonds (Figure 25) [70]. Selectfluor was used as the FAT reagent to furnish a selection of primary, secondary and tertiary benzyl fluorides with different

• disclosed the use of catalytic amounts of the organic dye Acr+-Mes under visible-light irradiation in combination with stoichiometric amounts of Selectfluor to achieve benzylic fluorination (Figure 29) [74]. It was proposed that a SET between Selectfluor and the photoexcited catalyst liberated fluoride and

Electrophotochemical metal-catalyzed synthesis of alkylnitriles from simple aliphatic carboxylic acids

• Yukang Wang,
• Yan Yao and
• Niankai Fu

Beilstein J. Org. Chem. 2024, 20, 1497–1503, doi:10.3762/bjoc.20.133

• esters, the so called "Barton esters", for decarboxylative cyanation of aliphatic acids with tosyl cyanide as the nitrile source under visible light irradiation at room temperature [21][22]. Although two synthetic steps are required, this is the first practical decarboxylative cyanation protocol because

• by anodic oxidation and visible light irradiation of the Ce species in a sequential fashion [38][39][40][41][42][43][44][45]. Therefore, the anodic electrode potential for this process could be substantially reduced. In doing so, a low working potential at the anode offers the opportunity for

• , experiments using stoichiometric Cu(II) and Ce(IV) indicated that the radical decarboxylative cyanation reaction can only occur under light irradiation. In contrast, reaction with Ce(III) exhibited nearly no reactivity, demonstrating the crucial roles of anodic oxidation and light irradiation to the

Synthesis of 4-functionalized pyrazoles via oxidative thio- or selenocyanation mediated by PhICl₂ and NH₄SCN/KSeCN

• Jialiang Wu,
• Haofeng Shi,
• Xuemin Li,
• Jiaxin He,
• Chen Zhang,
• Fengxia Sun and
• Yunfei Du

Beilstein J. Org. Chem. 2024, 20, 1453–1461, doi:10.3762/bjoc.20.128

• presented a method for the C–H thiocyanation of pyrazoles by using a sustainable catalyst of graphite-phase carbon nitride (g-C3N4) under visible light irradiation (Scheme 1c) [2]. Furthermore, Yao harnessed an electrochemical approach to form the electrophilic SCN+ intermediate, which reacted with

Generation of alkyl and acyl radicals by visible-light photoredox catalysis: direct activation of C–O bonds in organic transformations

• Mithu Roy,
• Bitan Sardar,
• Itu Mallick and
• Dipankar Srimani

Beilstein J. Org. Chem. 2024, 20, 1348–1375, doi:10.3762/bjoc.20.119

• -mediated deoxygenative trifluoromethylation technique worked with both benzylic and unactivated thiocarbonates. The proposed mechanism starts with the homolysis of (bpy)Cu(III)(CF3)3 by blue-light irradiation, which produces CF3 radicals and (bpy)Cu(II)(CF3)2. Subsequently, the interaction between the CF3

• reduction of xanthates. Under blue-light irradiation, xanthates were reacted with B2cat2 (19) in dimethylacetamide (DMAc), providing the borylated product in decent yield. The methodology was metal-free and did not require conventional heating. Nevertheless, the borylation process was limited to secondary

• directly activated via photoredox catalysis. In 2018, Doyle and co-workers [54] documented a catalytic method for the deoxygenation of benzylic alcohols to toluenes, utilizing phosphines and photoredox catalyst under visible-light irradiation (Scheme 18). In this method, they were able to synthesize

Transition-metal-catalyst-free electroreductive alkene hydroarylation with aryl halides under visible-light irradiation

• Kosuke Yamamoto,
• Kazuhisa Arita,
• Masami Kuriyama and
• Osamu Onomura

Beilstein J. Org. Chem. 2024, 20, 1327–1333, doi:10.3762/bjoc.20.116

• conditions. The key to success is the use of 1,3-dicyanobenzene as a redox mediator and visible-light irradiation, which effectively suppresses the formation of simple reduction, i.e., hydrodehalogenation, products to afford the desired products in good to high yields. Mechanistic investigations proposed

• ][53]. Furthermore, odd-numbered [n]cumulenes have proven to be effective redox mediators for electroreductive radical borylation of unactivated aryl chlorides without visible-light irradiation by the group of Milner [54]. Herein, we report transition-metal-catalyst-free electroreductive alkene

• hydroarylation with (hetero)aryl halides using 1,3-dicyanobenzene as a redox mediator under visible-light irradiation. Results and Discussion We began the investigation of the electroreductive hydroarylation using methyl 4-chlorobenzoate (1a) and methyl acrylate (2a) as model substrates (Table 1). After

Light on the sustainable preparation of aryl-cored dibromides

• Fabrizio Roncaglia,
• Alberto Ughetti,
• Nicola Porcelli,
• Biagio Anderlini,
• Andrea Severini and
• Luca Rigamonti

Beilstein J. Org. Chem. 2024, 20, 1076–1087, doi:10.3762/bjoc.20.95

• be employed in two variants modulated by light irradiation. This external switch can be used to selectively trigger side-chain or core halogenation. Keywords: aryl halides; benzyl halides; bromination; sustainability; Introduction Activation through halogens has become a key strategy in achieving

• ] resulting in easier recyclability. Light irradiation often significantly influences the selectivity of halogenation processes. Photolytic cleavage of molecular halogens gives rise to radicals that are known to favour benzylic functionalisation [17]. Conversely, the same molecular halogens exhibit prominent

• incorporation of the halogen into the product (no bromide byproducts are generated). Unfortunately, the safety and selectivity advantages of using NBS are counterbalanced by other issues. Specifically, light irradiation is often ineffective as an initiator for NBS [26][30], introducing the necessity to add a

Synthesis and characterization of water-soluble C₆₀–peptide conjugates

• Yue Ma,
• Lorenzo Persi and
• Yoko Yamakoshi

Beilstein J. Org. Chem. 2024, 20, 777–786, doi:10.3762/bjoc.20.71

• most other solvents. C60–oligo-Lys and C60–oligo-Glu were characterized by 1H and 13C NMR. Photoinduced 1O2 generation was observed in the most soluble C60–oligo-Lys conjugate under visible light irradiation (527 nm) to show the potential of this highly water-soluble molecule in biological systems, for

• the HRESIMS results (Figure S2, Supporting Information File 1), it was confirmed that the highly water-soluble compound 5a was successfully synthesized. 1O2 generation under visible light irradiation To preliminarily evaluate the synthesized C60–oligo-Lys (5a) as a PS, generation of singlet oxygen was

• measured by the ESR spin trapping method under irradiation of visible light (527 nm green LED). 4-Oxo-TEMP was used as a spin trapping reagent to form an adduct with 1O2, i.e., 4-oxo-TEMPO, which was observed by ESR (Figure 7b). As shown in Figure 7a, upon visible light irradiation, three peaks

SOMOphilic alkyne vs radical-polar crossover approaches: The full story of the azido-alkynylation of alkenes

• Julien Borrel and
• Jerome Waser

Beilstein J. Org. Chem. 2024, 20, 701–713, doi:10.3762/bjoc.20.64

• source. Upon light irradiation, it can release an azide radical by homolysis of the I−N3 bond [46]. We were pleased to see that irradiation of a mixture of styrene (1a), Ph-EBX (2) and Ts-ABZ (3) afforded 17% isolated yield of the desired homopropargylic azide 4a (Table 1, entry 1). Heating the reaction

• under blue light irradiation afforded 4a in 17% NMR yield (Table 2, entry 1). The major byproduct formed during the transformation was identified as diazide 6. When a copper photocatalyst is involved, a lot of diazidation can be observed. We assumed it could be caused by the reaction of Ts-ABZ (3) with

• potassium to tetrabutylammonium (7) reduced the yield to 14% (Scheme 2A). When TMS-alkyne 8 was used, no product formation occurred. In this case, we observed that the initial reaction mixture before light irradiation was colorless. This was surprising, as in all the previous experiments a yellow/orange

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

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

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

• radicals were successfully generated by subjecting NHPI esters to light irradiation in the presence of the photoreductant 1,6-bis(dimethylamino)pyrene (BDMAP). Following their initial discovery, multiple studies have shown their versatility as radical progenitors under thermal, photochemical, and

• readers to recently published review articles for additional discussion [30][31]. Discussion Mechanism under photochemical conditions In this section we provide a summary of the various conditions and activation modes employed in radical reactions of NHPI esters using visible-light irradiation. Upon

• type addition reactions (Scheme 4A). In 1991, Okada and co-workers reported the addition of alkyl radicals to α,β-unsaturated ketones, by subjecting NHPI esters to visible-light irradiation in the presence of the photocatalyst [Ru(bpy)3]Cl2 and the reductant 1-benzyl-1,4-dihydronicotinamide (BNAH) [37