Unprecedented visible light-initiated topochemical [2 + 2] cycloaddition in a functionalized bimane dye

• Metodej Dvoracek,
• Brendan Twamley,
• Mathias O. Senge and
• Mikhail A. Filatov

Beilstein J. Org. Chem. 2025, 21, 500–509, doi:10.3762/bjoc.21.37

• crystal lattice and are often reversible, requiring either high-energy light or heat for initiation [6][7][8]. Notably, topochemical polymerizations align with the principles of green chemistry, as they are solvent-free and do not involve toxic reagents [9]. The highly ordered and uniform nature of

• react and Me2B did not. One possible explanation lies in the light source used for irradiation. The emission wavelength (405 nm) is within 2 nm of the λmax of Cl2B (as a solution in DCM), allowing it to absorb the initiation light with much greater intensity. Additionally, Cl2B has a higher molar

Giese-type alkylation of dehydroalanine derivatives via silane-mediated alkyl bromide activation

• Perry van der Heide,
• Michele Retini,
• Fabiola Fanini,
• Giovanni Piersanti,
• Francesco Secci,
• Daniele Mazzarella,
• Timothy Noël and
• Alberto Luridiana

Beilstein J. Org. Chem. 2024, 20, 3274–3280, doi:10.3762/bjoc.20.271

• , alkyl radicals have been produced from alkyl halides, using azobisisobutyronitrile (AIBN) as initiator, promoting a tin-mediated XAT (Figure 1a) [8][9]. However, tin-based compounds are highly toxic and require harsh conditions for the initiation event. Fortunately, a renaissance in the field of

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

• was demonstrated to be scalable for natural products such as sclareolide and protected ʟ-valine. The proposed mechanism involves a radical chain process. Initiation occurs by nitrate-mediated or direct electrochemical anodic oxidation, followed by fluorination with Selectfluor. After fluorination, the

The Groebke–Blackburn–Bienaymé reaction in its maturity: innovation and improvements since its 21st birthday (2019–2023)

• Cristina Martini,
• Muhammad Idham Darussalam Mardjan and
• Andrea Basso

Beilstein J. Org. Chem. 2024, 20, 1839–1879, doi:10.3762/bjoc.20.162

Methyltransferases from RiPP pathways: shaping the landscape of natural product chemistry

• Maria-Paula Schröder,
• Isabel P.-M. Pfeiffer and
• Silja Mordhorst

Beilstein J. Org. Chem. 2024, 20, 1652–1670, doi:10.3762/bjoc.20.147

• recombinant elements” (PURE) was developed by Shimizu et al. [45]. PURE contains all the necessary components of the Escherichia coli ribosomal machinery, such as the ribosome, initiation, elongation, and release factors, and pre-charged tRNAs. In the first step, mRNA or a plasmid containing the desired

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

• (sp3)–H fluorination. They demonstrated this reaction primarily on alkyl substrates, but 5 secondary benzylic substrates were also shown to undergo the reaction effectively (Figure 19) [60]. The authors proposed the transformation occurred via established triethylborane autoxidation initiation and

Activity assays of NnlA homologs suggest the natural product N-nitroglycine is degraded by diverse bacteria

• Kara A. Strickland,
• Brenda Martinez Rodriguez,
• Ashley A. Holland,
• Shelby Wagner,
• Michelle Luna-Alva,
• David E. Graham and
• Jonathan D. Caranto

Beilstein J. Org. Chem. 2024, 20, 830–840, doi:10.3762/bjoc.20.75

• ], there is far less known regarding the environmental biodegradation pathways of linear nitramine contaminants. Biodegradations of NDAB by the fungus Phanerochaete chrysosporium and the bacterium Methylobacterium sp. strain JS178 have been reported [17][18]. Initiation of the P. chrysosporium degradation

• these, four were fully isolated and characterized. Each isolated homolog exhibited similar oligomerization and heme occupancy as Vs NnlA. In addition, we confirmed by in vitro assays that initiation of NNG degradation activity by the NnlA requires reduction of the heme, verifying the necessity of the

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

• , which incorporate both radical and ionic bond-forming steps into a single synthetic operation [16][17]. The success of radical reactions is intimately linked to the mechanisms of their initiation and the radical progenitor employed. Amongst the many progenitors that are available, carboxylic acids are

• overview of the diverse mechanisms that have been proposed for radical based transformations initiating from NHPI esters. The discussion is organized into four sections: (i) mechanisms under photochemical conditions, (ii) initiation by metal catalysis and stoichiometric reductants, (iii) N-heterocyclic

• -type additions. However, an alternative radical chain mechanism has been discussed in the literature [62] (Scheme 14). In this instance, chain initiation takes place through photoinduced SET, enabled by EDA complex formation between the reductant N-(n-butyl)-1,4-dihydronicotinamide (BuNAH) and an NHPI

Using the phospha-Michael reaction for making phosphonium phenolate zwitterions

• Matthias R. Steiner,
• Max Schmallegger,
• Larissa Donner,
• Johann A. Hlina,
• Christoph Marschner,
• Judith Baumgartner and
• Christian Slugovc

Beilstein J. Org. Chem. 2024, 20, 41–51, doi:10.3762/bjoc.20.6

• this zwitterion formation is of great importance since it is the initiation step for the catalytic cycle in Michael reactions [8]. Generally, the conjugate addition is favored for strong nucleophiles, which is why electron-rich trialkylphosphines were among the first catalysts used in this type of

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

• macrocycle with a crown ether segment attached through the β-positions of the two pyrrole rings located oppositely to each other, hovering above the porphyrin plane [40]. The initiation of these research topics was crucial for the search of simple chemical models for haemoglobins and cytochromes, as well as

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

• an initiator molecule; M represents a monomer molecule; Pi represents a polymer chain with i repeating units; S represents a solvent molecule; and a dot indicates free radical species. These reactions are classified into four elementary steps: initiation, propagation, termination, and transfer. The

• initiation step includes Equation 1 and Equation 2, when the thermal initiator decomposes into two small-molecule radical species and the first monomer adds to the growing chain to form the first repeating unit. The propagation step is depicted in Equation 3 when monomers take turns to undergo radical

• negative free energy of polymerization and the latter an adequate reactivity of the monomer, stability of the derived free radical, and a low proportion of side reactions. A slow rate of chain initiation, a fast rate of chain propagation, and a rapid rate of chain termination are key features of

α-(Aminomethyl)acrylates as acceptors in radical–polar crossover 1,4-additions of dialkylzincs: insights into enolate formation and trapping

• Angel Palillero-Cisneros,
• Paola G. Gordillo-Guerra,
• Fernando García-Alvarez,
• Olivier Jackowski,
• Franck Ferreira,
• Fabrice Chemla,
• Joel L. Terán and
• Alejandro Perez-Luna

Beilstein J. Org. Chem. 2023, 19, 1443–1451, doi:10.3762/bjoc.19.103

• enolate and a new R• that propagates the radical chain (Scheme 1). Initiation occurs upon oxidation of the dialkylzinc reagent by oxygen. The feasibility of such 1,4-addition reactions is fully reliant on the ease of the intermediate enoxyl radical to undergo alkylzinc-group transfer. Secondary α-carbonyl

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

• numerous similar attributes, halogen bonding has also proven to be a viable alternative in methodologies that rely on hydrogen bond initiation. For example, both halogen- and hydrogen bonding can be used in supramolecular chemistry as the binding mechanism in photoresponsive receptors [73][74][75][76][77

• cycloaddition reactions that occur without transition metal catalysts, the unexpected initiation of single electron transfer (SET) processes or photochemical transformations, and even proton transfers that appear to defy pKa limitations. The reaction pathways followed by iodonium ylides and Lewis basic reaction

Eschenmoser coupling reactions starting from primary thioamides. When do they work and when not?

• Lukáš Marek,
• Jiří Váňa,
• Jan Svoboda and
• Jiří Hanusek

Beilstein J. Org. Chem. 2023, 19, 808–819, doi:10.3762/bjoc.19.61

• -dimethyl-1,4-dihydroisoquinolin-3(2H)-one and isoquinoline-1,3(2H,4H)-dione were prepared using adapted procedures described in the literature [29][30][37] and their subsequent selective monobromination to 2b or 3 was achieved with NBS in chloroform under MCPBA initiation (see Supporting Information File 1

Investigation of cationic ring-opening polymerization of 2-oxazolines in the “green” solvent dihydrolevoglucosenone

• Solomiia Borova and
• Robert Luxenhofer

Beilstein J. Org. Chem. 2023, 19, 217–230, doi:10.3762/bjoc.19.21

• acid polymer termini from the initiation were observed, and apparently only syntheses of polymers with a low molar mass could be achieved. In addition, the specific equipment necessary for supercritical CO2 applications will limit its widespread use. Dihydrolevoglucosenone (DLG) is a dipolar aprotic

• initiating group (which equals the concentration of the propagation species [P*] if a fast and quantitative initiation is achieved), [M]0 is the initial concentration of the monomer, and t is the reaction time. Considering that kp is constant and [P*] should be constant and equal to [I]0, a linear plot of

• initiation. The monomer conversion reached more than 95% after 3 h of incubation (Figure 2a). The 1H NMR spectra of the polymer solutions after complete monomer conversion display significant signals at 1.06 ppm and 3.4 ppm attributed to the methyl group in the side chain and PEtOx backbone, respectively

Insight into oral amphiphilic cyclodextrin nanoparticles for colorectal cancer: comprehensive mathematical model of drug release kinetic studies and antitumoral efficacy in 3D spheroid colon tumors

• Sedat Ünal,
• Gamze Varan,
• Juan M. Benito,
• Yeşim Aktaş and
• Erem Bilensoy

Beilstein J. Org. Chem. 2023, 19, 139–157, doi:10.3762/bjoc.19.14

• 1.039 and 0.450, respectively. Similarly, the n value of Korsmeyer–Peppas above 0.85 indicates that the release mechanism is realized by super case II [44]. This value was interpreted as indicative of the release seen with the erosion of the nanoparticle material and the initiation of polymer relaxation

Redox-active molecules as organocatalysts for selective oxidative transformations – an unperceived organocatalysis field

• Elena R. Lopat’eva,
• Igor B. Krylov,
• Dmitry A. Lapshin and
• Alexander O. Terent’ev

Beilstein J. Org. Chem. 2022, 18, 1672–1695, doi:10.3762/bjoc.18.179

• ] (Scheme 36). One of the emerging areas in the chemistry of iodine(III) reagents with high synthetic potential is the visible-light induced I–O bond homolysis [152], which is currently employed mainly for the initiation of chain processes or stoichiometric oxidations, but definitely should find application

Oxa-Michael-initiated cascade reactions of levoglucosenone

• Julian Klepp,
• Thomas Bousfield,
• Hugh Cummins,
• Sarah V. A.-M. Legendre,
• Jason E. Camp and
• Ben W. Greatrex

Beilstein J. Org. Chem. 2022, 18, 1457–1462, doi:10.3762/bjoc.18.151

• during the reaction, and the formation of the bridged species is thermodynamically favored, except in the case of 5-methylfurfural and pyrrole-2-carboxaldehyde. This is the first report detailing this type of aldol/Michael cascade involving oxa-Michael initiation. Keywords: cascade reactions; green

• bridged α,β-unsaturated ketones; however, these reactions do not involve initiation by an oxa-Michael addition [23][24]. The reaction between 1 and aromatic ketones under basic conditions is analogous to the well-known aldol/Michael cascade reaction observed between aldehydes and enolates giving di- and

High-speed C–H chlorination of ethylene carbonate using a new photoflow setup

• Takayoshi Kasakado,
• Takahide Fukuyama,
• Tomohiro Nakagawa,
• Shinji Taguchi and
• Ilhyong Ryu

Beilstein J. Org. Chem. 2022, 18, 152–158, doi:10.3762/bjoc.18.16

• chlorination, which is consistent with the requirement of photoirradiation for the purpose of radical initiation. Near-complete selectivity for single chlorination required the low conversion of ethylene carbonate such as 9%, which was controlled by limited introduction of chlorine gas. At a higher conversion

• ; ethylene carbonate; photo flow reactor; vinylene carbonate; Introduction The C–H chlorination by molecular chlorine is a highly exothermic reaction that proceeds via a radical chain mechanism as illustrated in Scheme 1 [1][2][3][4][5][6]. Frequently, photoirradiation is used for radical initiation through

• ), chloroethylene carbonate (2) was obtained in good to excellent selectivity by tuning the flow rates of 1 and chlorine gas. Partial irradiation of the flow channel is sufficient for the C–H chlorination, consistent with the requirement for light irradiation for the radical initiation step. If we apply the

Iron-catalyzed domino coupling reactions of π-systems

• Austin Pounder and
• William Tam

Beilstein J. Org. Chem. 2021, 17, 2848–2893, doi:10.3762/bjoc.17.196

• the initiation of a multistep reaction is through the generation of an organoiron species. This can occur by the oxidative insertion of a low-valent iron into a C–X bond (Scheme 2). Evidently, iron in low oxidation states may operate as an iron-centered nucleophile, and catalyze reactions involving

Exfoliated black phosphorous-mediated CuAAC chemistry for organic and macromolecular synthesis under white LED and near-IR irradiation

• Azra Kocaarslan,
• Zafer Eroglu,
• Önder Metin and
• Yusuf Yagci

Beilstein J. Org. Chem. 2021, 17, 2477–2487, doi:10.3762/bjoc.17.164

• has set a milestone as a new and effective method for the synthesis of macromolecules [11]. Initiation of this reaction photocatalytically provides many advantages for the synthetic methodologies including bioconjugation, labeling, surface functionalization, dendrimer synthesis, polymer synthesis, and

Correction: Amine–borane complex-initiated SF₅Cl radical addition on alkenes and alkynes

• Audrey Gilbert,
• Pauline Langowski,
• Marine Delgado,
• Laurent Chabaud,
• Mathieu Pucheault and
• Jean-François Paquin

Beilstein J. Org. Chem. 2021, 17, 1725–1726, doi:10.3762/bjoc.17.120

• , France 10.3762/bjoc.17.120 Keywords: amine–borane complex; pentafluorosulfanyl chloride; pentafluorosulfanyl substituent; radical addition; radical initiation; The stereochemistry of some alkene products (2i–k) in Scheme 4 of the original publication was misattributed. The corrected structures are

A systems-based framework to computationally describe putative transcription factors and signaling pathways regulating glycan biosynthesis

• Theodore Groth,
• Rudiyanto Gunawan and
• Sriram Neelamegham

Beilstein J. Org. Chem. 2021, 17, 1712–1724, doi:10.3762/bjoc.17.119

• core 3 and core 4 glycans can occur during disease, and thus this classification includes core 3-forming B3GNT6 and core 4-forming GCNT3. Other O-glycan core types are rare in nature. 8) Chondroitin sulfate and heparan sulfate initiation: Chondroitin and heparan sulfate glycosaminoglycans all have a

• adds glucuronic acid to the terminal galactose. Also involved in the formation of this core is FAM20B, a kinase that 2-O-phosphorylates xylose. At this point, the addition of GalNAc to GlcA by CSGALNACT1 and 2 results in the initiation of chondroitin sulfate chains. The attachment of GlcNAc by EXTL3 to

Volatile emission and biosynthesis in endophytic fungi colonizing black poplar leaves

• Christin Walther,
• Pamela Baumann,
• Katrin Luck,
• Beate Rothe,
• Peter H. W. Biedermann,
• Jonathan Gershenzon,
• Tobias G. Köllner and
• Sybille B. Unsicker

Beilstein J. Org. Chem. 2021, 17, 1698–1711, doi:10.3762/bjoc.17.118

• : initiation and activation of polymerase (95 °C/5 min); followed by 35 cycles of denaturation (95 °C/30 s), annealing (65 °C/30 s) and elongation (72 °C/90 s) and a single, final elongation step (72 °C/10 min). For gel electrophoresis, 4 µL PCR product was mixed with one drop loading dye (0.3 mL 30% glycerol