Antibiofilm and cytotoxic metabolites from the entomopathogenic fungus Samsoniella aurantia

• Rita Toshe,
• Syeda J. Khalid,
• Blondelle Matio Kemkuignou,
• Esteban Charria-Girón,
• Paul Eckhardt,
• Birthe Sandargo,
• Kunlapat Nuchthien,
• J. Jennifer Luangsa-ard,
• Till Opatz,
• Hedda Schrey,
• Sherif S. Ebada and
• Marc Stadler

Beilstein J. Org. Chem. 2025, 21, 327–339, doi:10.3762/bjoc.21.23

• ) begins with an acetate moiety that is extended six times by HR-PKS, programmed C-methylations took place after the first and second extensions with a cycle of full reduction occurring after the first extension. Subsequently, four acetate extensions with programmed reductions and dehydrations to afford β

Non-covalent organocatalyzed enantioselective cyclization reactions of α,β-unsaturated imines

• Sergio Torres-Oya and
• Mercedes Zurro

Beilstein J. Org. Chem. 2024, 20, 3221–3255, doi:10.3762/bjoc.20.268

• carbanion to the isocyanate group forming intermediate B which undergoes protonation yielding the product. The authors attempted to perform different reductions of the products without any success. However, they performed a gram scale version of the transformation obtaining the product in comparable yields

Advances in the use of metal-free tetrapyrrolic macrocycles as catalysts

• Mandeep K. Chahal

Beilstein J. Org. Chem. 2024, 20, 3085–3112, doi:10.3762/bjoc.20.257

• -free meso-tetra(pentafluorophenyl)porphyrin (67) as a HER electrocatalyst using TsOH (p-toluenesulfonic acid) as a proton donor in THF [111]. Macrocycle 67 undergoes two reversible one-electron reductions at E1/2 = −1.14 V and −1.54 V yielding radical anion [67]˙− and a dianion species [67]2−. Upon

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

Synthesis and conformational analysis of pyran inter-halide analogues of ᴅ-talose

• Olivier Lessard,
• Mathilde Grosset-Magagne,
• Paul A. Johnson and
• Denis Giguère

Beilstein J. Org. Chem. 2024, 20, 2442–2454, doi:10.3762/bjoc.20.208

• halogenated analogues. There are reductions in the C1–C2–C3–C4 torsion angles for the halogenated pyrans as compared to compound 18 (–56.58°) (Table 3, entry 4). The decrease depends on the size of the halogen at C4 (F: –49.4°; Cl: –46.9°; Br: –46.5°; I: –46°). There is also a reduction in the C2–C3–C4–C5

Electrocatalytic hydrogenation of cyanoarenes, nitroarenes, quinolines, and pyridines under mild conditions with a proton-exchange membrane reactor

• Koichi Mitsudo,
• Atsushi Osaki,
• Haruka Inoue,
• Eisuke Sato,
• Naoki Shida,
• Mahito Atobe and
• Seiji Suga

Beilstein J. Org. Chem. 2024, 20, 1560–1571, doi:10.3762/bjoc.20.139

• , and pyridines using PEM reactors [51][52]. In this context, we have focused on the synthesis of nitrogen-containing molecules using a PEM reactor. Herein, we report the application of a PEM reactor for the reduction of cyanoarenes, nitroarenes, quinolines, and pyridines. These reductions proceeded

Kinetically stabilized 1,3-diarylisobenzofurans and the possibility of preparing large, persistent isoacenofurans with unusually small HOMO–LUMO gaps

• Qian Liu and
• Glen P. Miller

Beilstein J. Org. Chem. 2024, 20, 1099–1110, doi:10.3762/bjoc.20.97

• -diarylisobenzofurans 3 and 23. The latter reductions in the presence of zinc likely proceed through the corresponding ketols which are known to undergo ring closure in acidic solution [10][11]. These syntheses utilizing mesitylene or 1,3,5-triethylbenzene are considerably simpler than other approaches that would place

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

• yields of 85% after 20 minutes of stirring. The nano-TiO2 catalyst was easily recovered by centrifugation, where it could be reused up to four times, without any reductions in product conversion. What holds back the efficiency of this nanocatalytic protocol is the application of conventional heating, as

Multi-redox indenofluorene chromophores incorporating dithiafulvene donor and ene/enediyne acceptor units

• Christina Schøttler,
• Kasper Lund-Rasmussen,
• Line Broløs,
• Philip Vinterberg,
• Ema Bazikova,
• Viktor B. R. Pedersen and
• Mogens Brøndsted Nielsen

Beilstein J. Org. Chem. 2024, 20, 59–73, doi:10.3762/bjoc.20.8

• reduction. The pyrrolo-annelated dimer 13 showed a reversible oxidation at +0.42 V followed by an irreversible oxidation at +1.01 V, and two reversible reductions at −1.48 V and −1.81 V. Here, the acceptor properties are not promoted by incorporating an acceptor unit as in 15, but instead by the

• -electron reductions at −1.63 V and −1.89 V, indicating that the larger conjugated system of compound 27 does not significantly change the redox properties of the compound. Compounds 26 and 27 lack the DTF donor part and are hence oxidized at significantly higher potentials than the other compounds. On the

• , incorporating different dithiafulvenes and acetylenic scaffolds, such as acetylenic radiaannulenes. The compounds have strong absorptions in the visible region and undergo reversible (or quasi-reversible) oxidations and reductions. We have also presented two new fluorene-extended dithiafulvenes, which also

Selectivity control towards CO versus H₂ for photo-driven CO₂ reduction with a novel Co(II) catalyst

• Lisa-Lou Gracia,
• Philip Henkel,
• Olaf Fuhr and
• Claudia Bizzarri

Beilstein J. Org. Chem. 2023, 19, 1766–1775, doi:10.3762/bjoc.19.129

• that the energy barriers of the reactions shown in Equation 2 and Equation 3 are lowered. In fact, the formation of the radical anion CO2−· takes place at −1.9 V versus normal hydrogen electrode (NHE), while the proton-assisted reductions of CO2 to CO and formic acid happen at −0.53 V and −0.61 V

• profile of redox processes (Figure 4a, black lines). In particular, two irreversible reductions occur at the cathodic potentials −1.53 V and −1.9 V versus ferrocene. These electrochemical processes may correspond to the first and second reduction of the metal core Co(II)/Co(I) and Co(I)/Co(0

Benzoimidazolium-derived dimeric and hydride n-dopants for organic electron-transport materials: impact of substitution on structures, electrochemistry, and reactivity

• Swagat K. Mohapatra,
• Khaled Al Kurdi,
• Samik Jhulki,
• Georgii Bogdanov,
• John Bacsa,
• Maxwell Conte,
• Tatiana V. Timofeeva,
• Seth R. Marder and
• Stephen Barlow

Beilstein J. Org. Chem. 2023, 19, 1651–1663, doi:10.3762/bjoc.19.121

• , resulting in 1g• and 1h• being more reducing monomers than their non-methoxylated analogues 1b• and 1e•, respectively. Cyclic voltammograms of both 1H and 12 both reveal irreversible oxidations (with the corresponding 1+ reductions seen in subsequent reductive cycles, see Figure 6 for examples). These 1H

• of 1h2 and VII to form VII•– under the conditions used in the present study is complete much sooner than reactions using 1b2 or 1g2, consistent with the ET-first reaction of 3h2 being more rapid than that for either 1b2 or 1g2. Furthermore, the presumed “cleavage-first” reductions of VII•– to VII2

Tying a knot between crown ethers and porphyrins

• Maksym Matviyishyn and
• Bartosz Szyszko

Beilstein J. Org. Chem. 2023, 19, 1630–1650, doi:10.3762/bjoc.19.120

• with trifluoroacetic acid (TFA) resulted in a cationic 40-H+. Cyclic voltammetry and differential pulse voltammetry were performed to investigate the electrochemical properties of 40-H+. The cation exhibited two reversible oxidations and two to three reductions. The redox potentials were influenced by

One-pot nucleophilic substitution–double click reactions of biazides leading to functionalized bis(1,2,3-triazole) derivatives

• Hans-Ulrich Reissig and
• Fei Yu

Beilstein J. Org. Chem. 2023, 19, 1399–1407, doi:10.3762/bjoc.19.101

• revealed that the N-benzyl groups were still intact, however, we cannot exclude that partial reductions had occurred at other positions of this relatively complex molecule. Thus, better conditions for the clean transformation of compounds such as 21 into carbohydrate mimetics have still to be developed. We

Enabling artificial photosynthesis systems with molecular recycling: A review of photo- and electrochemical methods for regenerating organic sacrificial electron donors

• Grace A. Lowe

Beilstein J. Org. Chem. 2023, 19, 1198–1215, doi:10.3762/bjoc.19.88

• solvent polarity [24][25]. Hence, it is important when considering new reagents and catalysts to only compare potentials measured in conditions as close to the photocatalytic conditions as possible. For instance, quinones have 2 one-electron reductions in aprotic media and one two-electron reduction at a

• various acids [49]. This system is completely metal-free and uses one photocatalyst rather than separate sensitizer and catalyst species. However, the electron source for the reductions was a thiolate sacrificial donor and not water. Thiolates are used as redox mediators in other systems such as dye

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

• applications, the most marked difference between the two types of processes, however, is that conPET is more appropriate for redox-neutral reactions, whereas PEC is more appropriate for net oxidations or reductions due to the radical polar crossover nature of its reactivity [30][31]. In the former, the neutral

• -chloroanisole (Epred = −2.88 V vs SCE) were only obtained in yields of 6% and 4%, respectively, which the authors attributed to insufficient redox power of *DCA•− in its D1 state (*E1/2 = −2.60 V vs SCE) [53]. These results strongly contrast to the work of Lambert and Lin on e-PRC reductions with DCA (vide

• two polysulfide redox couples. However, K2CO3 was needed to quench liberated protons. A large variety of electron-poor aryl bromides bearing different functional groups readily underwent SET reductions to give biaryl cross-coupled products 4 in poor to excellent yields (20–93%) (Figure 15A). The

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

• radical, but is now assumed to proceed through the formation of an organosamarium intermediate, resulting from two successive single-electron reductions [66]. This strategy was successfully applied to the construction of variecolin intermediate 140 possessing a [5-8] ring system in its backbone (Scheme 28

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

• ) [30]. HAT reductions of the C9–C11 alkene followed to deliver arisugacin F (35), phenylpyropene C (36), pyripyropene E (38), and phenylpyropene F (41). The steric bulk of the manganese catalyst employed suppressed the undesired reaction with tetrasubstituted alkenes and led to the exclusive reaction

B–N/B–H Transborylation: borane-catalysed nitrile hydroboration

• Filip Meger,
• Alexander C. W. Kwok,
• Franziska Gilch,
• Dominic R. Willcox,
• Alex J. Hendy,
• Kieran Nicholson,
• Andrew D. Bage,
• Thomas Langer,
• Thomas A. Hunt and
• Stephen P. Thomas

Beilstein J. Org. Chem. 2022, 18, 1332–1337, doi:10.3762/bjoc.18.138

• transborylation (a σ-bond metathesis turnover method) has been used for borane-catalysed reductions of N-heteroarenes [28][29], and the borane-catalysed cyanation of enones [30]. Applying B–N/B–H transborylation to the hydroboration of nitriles would enable the development of a borane-catalysed hydroboration of

• noted that the borohydride-catalysed reductions generally proceed at lower reaction temperatures using 5 mol % NaBHEt3 [24]. Esters undergo stoichiometric reduction by H3B·SMe2 (see Supporting Information File 1) [32]; therefore, chemoselective nitrile hydroboration highlights the benefit of this

Electrogenerated base-promoted cyclopropanation using alkyl 2-chloroacetates

• Kouichi Matsumoto,
• Yuta Hayashi,
• Kengo Hamasaki,
• Mizuki Matsuse,
• Hiyono Suzuki,
• Keiji Nishiwaki and
• Norihito Kawashita

Beilstein J. Org. Chem. 2022, 18, 1116–1122, doi:10.3762/bjoc.18.114

• consumed on the surface of the anode. To examine the scope and limitations, we carried out electrochemical reductions of various alkyl 2-haloacetates under the optimized conditions. Table 3 summarizes the results. The reaction of methyl 2-chloroacetate (3) afforded the corresponding compound 4 in 28% yield

Electrochemical hydrogenation of enones using a proton-exchange membrane reactor: selectivity and utility

• Koichi Mitsudo,
• Haruka Inoue,
• Yuta Niki,
• Eisuke Sato and
• Seiji Suga

Beilstein J. Org. Chem. 2022, 18, 1055–1061, doi:10.3762/bjoc.18.107

• conditions, and highly chemoselective reductions were achieved with the use of appropriate cathode catalysts. The use of a Pd/C cathode gave carbonyl compounds selectively. In contrast, saturated alcohols were obtained selectively with an Ir/C cathode. The reaction with H2O as a proton source was also

Cathodic generation of reactive (phenylthio)difluoromethyl species and its reactions: mechanistic aspects and synthetic applications

• Sadanobu Iwase,
• Shinsuke Inagi and
• Toshio Fuchigami

Beilstein J. Org. Chem. 2022, 18, 872–880, doi:10.3762/bjoc.18.88

• , one-electron and two-electron reductions of 1 seem to take place simultaneously to generate radical and anionic intermediates. In order to trap the radical intermediate, the constant potential cathodic reduction of 1 was performed in the presence of various olefins such as α-methylstyrene, cyclohexene

Inductive heating and flow chemistry – a perfect synergy of emerging enabling technologies

• Conrad Kuhwald,
• Sibel Türkhan and
• Andreas Kirschning

Beilstein J. Org. Chem. 2022, 18, 688–706, doi:10.3762/bjoc.18.70

• for the transfer hydrogenations (Pd) are reusable for several reductions without the need to adjust the overall reaction conditions (flow rate and residence time, temperature etc.). Multicomponent reactions (MCRs) are of particular interest in the field of flow chemistry because this enabling

Site-selective reactions mediated by molecular containers

• Rui Wang and
• Yang Yu

Beilstein J. Org. Chem. 2022, 18, 309–324, doi:10.3762/bjoc.18.35

• naphthalene and phthalimide mediated by cage host A. Cage host A-mediated selective 1,4-radical addition of o-quinone 10. Cyclodextrin-mediated site-selective reductions. Selective reduction of an α,ω-diazide compound mediated by water-soluble cavitand D. Selective radical reduction of α,ω-dihalides mediated

A comprehensive review of flow chemistry techniques tailored to the flavours and fragrances industries

• Guido Gambacorta,
• James S. Sharley and
• Ian R. Baxendale

Beilstein J. Org. Chem. 2021, 17, 1181–1312, doi:10.3762/bjoc.17.90

N-tert-Butanesulfinyl imines in the asymmetric synthesis of nitrogen-containing heterocycles

• Joseane A. Mendes,
• Paulo R. R. Costa,
• Miguel Yus,
• Francisco Foubelo and
• Camilla D. Buarque

Beilstein J. Org. Chem. 2021, 17, 1096–1140, doi:10.3762/bjoc.17.86