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

• neutral PDI and forms the aryl halide’s radical anion, which then undergoes C(sp2)–X bond fission to afford the aryl radical as a reactive intermediate. The aryl radical then either reacts via hydrogen atom transfer (HAT) with solvent molecules or Et3N•+ in an overall dehalogenation to furnish product 2

One-pot synthesis of dicyclopenta-fused peropyrene via a fourfold alkyne annulation

• Ji Ma,
• Yubin Fu,
• Junzhi Liu and
• Xinliang Feng

Beilstein J. Org. Chem. 2020, 16, 791–797, doi:10.3762/bjoc.16.72

• arylacetylenes in good yield [28][29]. However, the larger CP-PAHs beyond the pyrene core, or its extended analogs [30] remain elusive. Peropyrene (Scheme 1), as the higher homolog of pyrene, has recently attracted attention because of its promising applications in optoelectronics, e.g., for singlet fission

Diversity-oriented synthesis of spirothiazolidinediones and their biological evaluation

• Sambasivarao Kotha,
• Gaddamedi Sreevani,
• Lilya U. Dzhemileva,
• Milyausha M. Yunusbaeva,
• Usein M. Dzhemilev and
• Vladimir A. D’yakonov

Beilstein J. Org. Chem. 2019, 15, 2774–2781, doi:10.3762/bjoc.15.269

• hypodiploidal DNA peak appears 24 hours after the action of compounds 22, 20 and 17, which shows the inability to stop the fission cycle at the checkpoints, and ultimately, leads to cell death. Conclusion In summary, we have synthesized spirothiazolidinedione derivatives via a [2 + 2 + 2] cyclotrimerization

Excited state dynamics for visible-light sensitization of a photochromic benzil-subsituted phenoxyl-imidazolyl radical complex

• Yoichi Kobayashi,
• Yukie Mamiya,
• Katsuya Mutoh,
• Hikaru Sotome,
• Masafumi Koga,
• Hiroshi Miyasaka and
• Jiro Abe

Beilstein J. Org. Chem. 2019, 15, 2369–2379, doi:10.3762/bjoc.15.229

• and the spectral shift due to the benzil unit (from 582 nm to 556 nm). In PABI, which is a similar photochromic molecule to PIC, it was reported that the C–N bond fission occurs with the time constant of 140 fs and the broad absorption assigned to the biradical form was formed with a time constant of

Anomeric sugar boronic acid analogues as potential agents for boron neutron capture therapy

• Daniela Imperio,
• Erika Del Grosso,
• Silvia Fallarini,
• Grazia Lombardi and
• Luigi Panza

Beilstein J. Org. Chem. 2019, 15, 1355–1359, doi:10.3762/bjoc.15.135

• ; Introduction Boron neutron capture therapy (BNCT) belongs to the so-called binary therapies for cancer treatment. It is based on the fission reaction after a low-energy neutron capture by a 10B atom. The neutron capture reaction gives rise to two high linear energy transfer (LET) particles (an α-particle and a

Oxidative radical ring-opening/cyclization of cyclopropane derivatives

• Yu Liu,
• Qiao-Lin Wang,
• Zan Chen,
• Cong-Shan Zhou,
• Bi-Quan Xiong,
• Pan-Liang Zhang,
• Chang-An Yang and
• Quan Zhou

Beilstein J. Org. Chem. 2019, 15, 256–278, doi:10.3762/bjoc.15.23

• complex 126 is initially formed from the process of ligand exchange between the substrate and AgF2. The alkoxy radical 98 is produced via a single-electron oxidation by Ag–O bond homolysis. As a feature of the cyclopropane system, the radical 98 goes through a ring fission to form the alkyl radical 99

Nucleofugal behavior of a β-shielded α-cyanovinyl carbanion

• Rudolf Knorr and
• Barbara Schmidt

Beilstein J. Org. Chem. 2018, 14, 3018–3024, doi:10.3762/bjoc.14.281

• fission may also be used to generate different metal derivatives of the nucleofugal anions as equilibrium components. Fluoride-catalyzed, metal-free desilylation admitted carbonyl addition but blocked the retro-addition. Keywords: alkoxide fission; desilylation; fragmentation; retro-addition; reversible

• formally) heterolytic cleavage of C–C single bonds can provide cases of interest if it generates organometallic compounds under unusual conditions. The well-known cases of alkoxide fission [1][2][3] (top line of Scheme 1) may be viewed as a reversed formation of an alkoxide A1M1 from an organometallic C–M1

• and a carbonyl compound (R1)2C=O. Such a C–C fission (retro-addition reaction) can occur already near room temperature (rt) if the nucleofugal carbanion proves to be an electronically stabilized N≡C–CH2– [1] or allylic [2] species or a short-lived equilibrium component [3]. A cleavable alkoxide A1M1

One hundred years of benzotropone chemistry

• Arif Dastan,
• Haydar Kilic and
• Nurullah Saracoglu

Beilstein J. Org. Chem. 2018, 14, 1120–1180, doi:10.3762/bjoc.14.98

• ) [174]. Catalytic hydrogenation of 241 over Adams's catalyst (PtO2.H2) gave the diol 295 (Scheme 49) [162][165][174]. Treatment of 241 with alkaline hydrogen peroxide caused degradative fission to give o-carboxycinnamic acid (296) [165], while nitration of 241 with nitric acid in an acetic acid solution

Electrochemically modified Corey–Fuchs reaction for the synthesis of arylalkynes. The case of 2-(2,2-dibromovinyl)naphthalene

• Fabiana Pandolfi,
• Isabella Chiarotto and
• Marta Feroci

Beilstein J. Org. Chem. 2018, 14, 891–899, doi:10.3762/bjoc.14.76

• corresponding carbanion and halogen anion, can be achieved by a bielectronic cathodic process (Scheme 2). The electrolysis is carried out at a suitable controlled potential, i.e., at a potential that is negative enough to achieve the selective fission of the envisaged C–halogen bond [23]. Therefore, the

Phosphodiester models for cleavage of nucleic acids

• Satu Mikkola,
• Tuomas Lönnberg and
• Harri Lönnberg

Beilstein J. Org. Chem. 2018, 14, 803–837, doi:10.3762/bjoc.14.68

• reaction is a synchronous displacement (ANDN) when bond formation to the entering nucleophile is as advanced as bond fission to the departing nucleophile (A in Figure 2). In case the bond formation is more or less advanced than the bond fission, the reaction still is concerted but has an associative or

• fission of the intermediate to a 2´,3´-cyclic phosphate, leading to pH-independent cleavage, is much slower (Scheme 1). The rate of this reaction (black line in Figure 6) is only 2% of the interconversion rate of 2´,5´- and 3´,5´-diesters [44]. Studies with various uridine 3´-alkylphosphates have, however

• endocyclic cleavage of the phosphorane intermediate is more than 10 kcal mol−1 lower than that for the exocyclic cleavage, it is not clear whether a similar proton transfer from a phosphorane hydroxy ligand to the departing oxygen occurs concerted with the fission of P–O2´ and P–O3´ bonds or does protonation

From chemical metabolism to life: the origin of the genetic coding process

• Antoine Danchin

Beilstein J. Org. Chem. 2017, 13, 1119–1135, doi:10.3762/bjoc.13.111

Synthesis and enzymatic ketonization of the 5-(halo)-2-hydroxymuconates and 5-(halo)-2-hydroxy-2,4-pentadienoates

• Tyler M. M. Stack,
• William H. Johnson Jr. and
• Christian P. Whitman

Beilstein J. Org. Chem. 2017, 13, 1022–1031, doi:10.3762/bjoc.13.101

• , University of Texas, Austin, TX 78712, USA 10.3762/bjoc.13.101 Abstract 5-Halo-2-hydroxymuconates and 5-halo-2-hydroxy-2,4-pentadienoates are stable dienols that are proposed intermediates in bacterial meta-fission pathways for the degradation of halogenated aromatic compounds. The presence of the halogen

• pathway steps. This information is also useful to predict the fate of halogenated species once released into the environment. One major route for the degradation of aromatic compounds is the meta-fission pathway [6][7]. The enzymes and reactions of the meta-fission pathway in Pseudomonas putida mt-2 for

• monocyclic aromatic compounds (e.g., benzene, toluene, and alkyl-substituted derivatives) have been extensively studied for more than 60 years. Initially, the aromatic compound is converted to catechol or a catechol derivative. Subsequently, the resulting species undergoes meta-fission where this term refers

Versatile synthesis of the signaling peptide glorin

• Robert Barnett,
• Daniel Raszkowski,
• Thomas Winckler and
• Pierre Stallforth

Beilstein J. Org. Chem. 2017, 13, 247–250, doi:10.3762/bjoc.13.27

• study the emergence of multicellularity since they can exist in both a unicellular and a multicellular stage with a well-orchestrated developmental cycle linking the two [2]. The unicellular amoebae feed on bacteria and divide by binary fission. Upon depletion of their food source, they aggregate to

Genicunolide A, B and C: three new triterpenoids from Euphorbia geniculata

• Alia Farozi,
• Javid A. Banday and
• Shakeel A. Shah

Beilstein J. Org. Chem. 2015, 11, 2707–2712, doi:10.3762/bjoc.11.291

• observed upfield at δC 73.0–73.2 [44]. The densely populated ion peaks at m/z 221 (rings A/B) and 203 (221 − H2O.+), arising from the fission of 9, 11 and 8, 14 bonds in ring C, together with the downfield carbon signal at δC 89.5 placed the second tertiary hydroxy groups at C-9. The structure of compound

Photoinduced 1,2,3,4-tetrahydropyridine ring conversions

• Baiba Turovska,
• Henning Lund,
• Viesturs Lūsis,
• Anna Lielpētere,
• Edvards Liepiņš,
• Sergejs Beljakovs,
• Inguna Goba and
• Jānis Stradiņš

Beilstein J. Org. Chem. 2015, 11, 2166–2170, doi:10.3762/bjoc.11.234

• –carbon double bond in enamines to give the corresponding epoxides, however, in most cases they have not been isolated [36]. The hydroperoxide 2 reacts in the same way. Fission of the epoxide ring may be induced by the base itself producing 3. Attack of a second molecule of hydroperoxide 2 on the imine

• group of 3 oxidizes it to oxaziridine intermediate 4 (Figure 4), which then undergoes a slow nucleophilic ring fission followed by cyclization (Scheme 3) to give 5 (Figure 4). The reaction depicted in Scheme 2 proceeds as long as the hydroperoxide 2 is present in the solution, and the crude product

Copper-catalyzed aerobic radical C–C bond cleavage of N–H ketimines

• Ya Lin Tnay,
• Gim Yean Ang and
• Shunsuke Chiba

Beilstein J. Org. Chem. 2015, 11, 1933–1943, doi:10.3762/bjoc.11.209

• applications of the copper-catalyzed aerobic C–C bond fission of iminyl radical species for the synthesis of oxaspirocyclohexadienones as well as the electrophilic cyanation of Grignard reagents using the readily available pivalonitrile as a CN source. Results and Discussion We further explored the reactivity

• both aryl rings of the biaryl moiety, underwent the C–C bond fission process smoothly to afford oxaspirocyclized product 3b and biaryl alkene 4b in 48% and 35% yields, respectively, along with p-tolunitrile (5a) in 90% yield (Table 2, entry 1). The reactions of N–H ketimines having cyclopentyl and

• proposal. Next, we turned our attention to apply the present copper-catalyzed aerobic C–C bond fission process in the electrophilic cyanation of Grignard reagents. As carbonitriles are omnipresent components in various natural products, dyes and potent pharmaceutical drugs [60][61][62], new and versatile

Development of variously functionalized nitrile oxides

• Haruyasu Asahara,
• Keita Arikiyo and
• Nagatoshi Nishiwaki

Beilstein J. Org. Chem. 2015, 11, 1241–1245, doi:10.3762/bjoc.11.138

• single experimental step [1][2]. In addition, cycloadducts serve as precursors of polyfunctionalized compounds by ring opening reaction followed by N–O bond fission [2][3]. Hence, functionalized nitrile oxides are clearly useful for the preparation of more complex systems. However, because the precursors

The Shono-type electroorganic oxidation of unfunctionalised amides. Carbon–carbon bond formation via electrogenerated N-acyliminium ions

• Alan M. Jones and
• Craig E. Banks

Beilstein J. Org. Chem. 2014, 10, 3056–3072, doi:10.3762/bjoc.10.323

• –silicon bond (when an electroauxiliary is present) or direct carbon–hydrogen bond fission to afford the α-methoxylated product (Scheme 10) [67][68]. The direct anodic oxidation reaction to afford the N-acyliminium ion can be intercepted with a carbon nucleophile enantioselectively when a chiral auxiliary

A computational study of base-catalyzed reactions of cyclic 1,2-diones: cyclobutane-1,2-dione

• Nargis Sultana and
• Walter M. F. Fabian

Beilstein J. Org. Chem. 2013, 9, 594–601, doi:10.3762/bjoc.9.64

• compounds leads to the formation of relatively stable tetrahedral adducts (Scheme 1) [1]. These adducts further react either by (i) fission of the R2–C bond and migration of R2 (benzil–benzilic acid rearrangement, path A); (ii) fission of the R2–C bond without migration of R2 resulting in α-oxocarboxylic

• acids (path B); or (iii) fission of the carbonyl-C–sp3-C with formation of an aldehyde and carboxylic acid (path C). In the case of benzils, depending on the substituents on the aryl rings, all three types of reactions have been observed [2]. The benzilic acid rearrangement of cyclic 1,2-diones [3][4

• free energy of activation of the benzilic acid rearrangement (fission of the C1–C4 and concerted formation of the C2–C4 bond) via TS2 (ν = 246i cm–1) is ca. 15 kcal mol–1. The initial product P1a (1-carboxycyclopropanolate) is expected to easily convert to the final product 1

Zanthoxoaporphines A–C: Three new larvicidal dibenzo[de,g]quinolin-7-one alkaloids from Zanthoxylum paracanthum (Rutaceae)

• Fidelis N. Samita,
• Louis P. Sandjo,
• Isaiah O. Ndiege,
• Ahmed Hassanali and
• Wilber Lwande

Beilstein J. Org. Chem. 2013, 9, 447–452, doi:10.3762/bjoc.9.47

• , and column chromatography. Iodine–silica gel was employed as a developer to visualize the spots on the TLC plates. HRMS–EI were recorded with a JEOL JMS HX-110 mass spectrometer instrument, and EI analysis was performed by using the direct insertion probe (DIP) on a fission platform 11 mass

Inclusion of the insecticide fenitrothion in dimethylated-β-cyclodextrin: unusual guest disorder in the solid state and efficient retardation of the hydrolysis rate of the complexed guest in alkaline solution

• Dyanne L. Cruickshank,
• Natalia M. Rougier,
• Raquel V. Vico,
• Susan A. Bourne,
• Elba I. Buján,
• Mino R. Caira and
• Rita H. de Rossi

Beilstein J. Org. Chem. 2013, 9, 106–117, doi:10.3762/bjoc.9.14

• not the case under our reaction conditions; therefore we think that the type A complex is predominant for β-CD and DIMEB. Kinetic studies The hydrolysis reaction of fenitrothion takes place with P–O bond fission as shown in Scheme 1 [12] and it was studied in the presence of constant HO− and variable

Hydrophobic analogues of rhodamine B and rhodamine 101: potent fluorescent probes of mitochondria in living C. elegans

• Laurie F. Mottram,
• Safiyyah Forbes,
• Brian D. Ackley and
• Blake R. Peterson

Beilstein J. Org. Chem. 2012, 8, 2156–2165, doi:10.3762/bjoc.8.243

• Mitochondria undergo dynamic fusion and fission events that affect the structure and function of these critical energy-producing cellular organelles. Defects in these dynamic processes have been implicated in a wide range of human diseases including ischemia, neurodegeneration, metabolic disease, and cancer

• mitochondrial stains rhodamine 123, rhodamine 6G, and rhodamine B, as well as the structurally related fluorophores rhodamine 101, and basic violet 11, revealed that HRB and HR101 are the most potent mitochondrial probes, enabling imaging of mitochondrial motility, fusion, and fission in the germline and other

• expression of mitochondria-targeted fluorescent proteins. The high bioavailabilty of these novel fluorescent probes may facilitate the identification of agents and factors that affect diverse aspects of mitochondrial biology in vivo. Keywords: Caenorhabditis elegans; chemical biology; fission; fluorophores

Alkoxide-induced ring opening of bicyclic 2-vinylcyclobutanones: A convenient synthesis of 2-vinyl-substituted 3-cycloalkene-1-carboxylic acid esters

• Xiufang Ji,
• Zhiming Li,
• Quanrui Wang and
• Andreas Goeke

Beilstein J. Org. Chem. 2012, 8, 650–657, doi:10.3762/bjoc.8.72

• by 4a, the reaction begins with the nucleophilic exo-facial attack on the carbonyl group by an alkoxide ion to trigger the cleavage of the four-membered ring. The presence of a vinyl group facilitates the ring fission since the resultant carbanion can be stabilized by resonance. Protonation leads to

Isotopic labelling studies for a gold-catalysed skeletal rearrangement of alkynyl aziridines

• Paul W. Davies,
• Nicolas Martin and
• Neil Spencer

Beilstein J. Org. Chem. 2011, 7, 839–846, doi:10.3762/bjoc.7.96

• the most common fundamental steps in these skeletal rearrangements involves C–C bond fission through 1,2-migration. This step is triggered by the generation of carbocationic character, which is generally stabilised in some form, either by an adjacent gold atom or through extended delocalisation. While

• requires fission of three bonds: The propargylic C–N bond in ring expansion; the aryl–aziridinyl C–C bond in the 1,2 shift and the propargylic C–H bond for aromatisation (Scheme 3). The positioning of a deuterium atom at the benzylic carbon in 4 enables the carbons of the aziridine ring to be distinguished

• . Cycloisomerisation of 15 once again afforded a mixture of isotopomers of the 2,4-disubstituted pyrrole 21a/b alongside 2,5-disubstituted pyrrole 20 (Scheme 10). The formation of the isotopomers 17a, 19 and 21a with 13C-enrichment at C-5 confirms C–C bond fission between the aryl group and the aziridine during the

Kinetic evaluation of the solvolysis of isobutyl chloro- and chlorothioformate esters

• Malcolm J. D’Souza,
• Matthew J. McAneny,
• Dennis N. Kevill,
• Jin Burm Kyong and
• Song Hee Choi

Beilstein J. Org. Chem. 2011, 7, 543–552, doi:10.3762/bjoc.7.62

• to the chlorocarbonyl group in alkyl chloro- and chlorothioformates, the positive entropies and low solvent isotope effects pointed to a mechanism involving a unimolecular acyl–halogen bond fission. More recent studies on alkyl and aryl chlorothio-, chlorodithio-, and chlorothionoformate esters favor