Tandem Hock and Friedel–Crafts reactions allowing an expedient synthesis of a cyclolignan-type scaffold

• Viktoria A. Ikonnikova,
• Cristina Cheibas,
• Oscar Gayraud,
• Alexandra E. Bosnidou,
• Nicolas Casaretto,
• Gilles Frison and
• Bastien Nay

Beilstein J. Org. Chem. 2024, 20, 162–169, doi:10.3762/bjoc.20.15

• photooxygenation, Hock rearrangement and Friedel–Crafts reaction, which is supposed to proceed through aldehyde 3 (see further discussion below on the reaction mechanism). To complete this exploratory work, we envisaged to add an external aromatic nucleophile to the reaction mixture, namely 1,3,5-trimethoxybenzene

• was not formed, but the formation of aldehyde 3 could be observed during TLC monitoring. Furthermore, engaging previous dihydronaphthalene 4 in a Friedel–Crafts reaction with 5 in the presence of BF3·OEt2 and MgSO4 did not afford product 6. These observations are in agreement with a mechanism

• involvement of oxocarbenium species 7 and 7’ in a Friedel–Crafts reaction with 5, to explain the formation of 6 through an interrupted Hock cleavage mechanism. Confronting the yield of this transformation (86%) and the fact that only 7’, originating from 2’, could be an intermediate towards 6 in this

Copper-promoted C5-selective bromination of 8-aminoquinoline amides with alkyl bromides

• Changdong Shao,
• Chen Ma,
• Li Li,
• Jingyi Liu,
• Yanan Shen,
• Chen Chen,
• Qionglin Yang,
• Tianyi Xu,
• Zhengsong Hu,
• Yuhe Kan and
• Tingting Zhang

Beilstein J. Org. Chem. 2024, 20, 155–161, doi:10.3762/bjoc.20.14

• gram-scale preparation was carried out using 1a, that afforded the desired product in 96% yield (Scheme 4, reaction 4). To gain more insight into the reaction mechanism, several control experiments were carried out (Scheme 5). On one hand, the failure of substrates 10–15 to participate in the reaction

• probable mechanism is proposed. As shown in Scheme 5, ethyl bromoacetate (2a) undergoes attack by the dipolar aprotic solvent DMSO to afford the intermediate A. This intermediate then reacts with the bromine anion to give intermediate B. Dimethylsulfonium bromide or dimethyl thioether/molecular bromine

• . Reaction conditions: 1a (0.2 mmol), 2 (0.8 mmol), Cu(OAc)2·H2O (20 mol %), K2CO3 (0.2 mmol), DMSO (1.0 mL), stirred under air at 100 ºC for 12 h. Isolated yield. Further substrate scope investigations and gram-scale application. Control experiments and proposed mechanism. Optimization of the reaction

Perspectives on push–pull chromophores derived from click-type [2 + 2] cycloaddition–retroelectrocyclization reactions of electron-rich alkynes and electron-deficient alkenes

• Michio Yamada

Beilstein J. Org. Chem. 2024, 20, 125–154, doi:10.3762/bjoc.20.13

• -order kinetics, indicating a bimolecular process. Furthermore, their findings elucidated a compelling linear free-energy relationship between the rate constants and electronic characteristics of the para-substituents of the DCV electrophiles, implying a dipolar, zwitterionic mechanism. The researchers

• generalizing the elucidated reaction mechanism to other [2 + 2] CA–RE reactions involving TCNE and TCNQ as electrophiles might be difficult. They emphasized the significance of considering a pre-equilibrium state of the charge-transfer complexes between the alkynes and alkenes and mentioned that the

• emission increases when they are excited at 420 nm, resulting in white-light emission. The underlying mechanism governing these luminescence properties remains unknown. It has been established that 75 does not exhibit luminescence in its solid-state form, which is attributed to the quenching effects

Visible-light-induced radical cascade cyclization: a catalyst-free synthetic approach to trifluoromethylated heterocycles

• Chuan Yang,
• Wei Shi,
• Jian Tian,
• Lin Guo,
• Yating Zhao and
• Wujiong Xia

Beilstein J. Org. Chem. 2024, 20, 118–124, doi:10.3762/bjoc.20.12

• radicals. This method allows the efficient synthesis of various indole derivatives without the need of photocatalysts or transition-metal catalysts. Mechanism experiments indicate that the process involves a radical chain process initiated by the homolysis of Umemoto's reagent. This straightforward method

• precedent work [32] (see Supporting Information File 1), and the calculated quantum yield was 2.2, which revealed that one photon generates more than one product molecule. Based on preliminary experiments and previous reports [33][34], we propose a plausible mechanism (Scheme 4). Upon light irradiation

• derivatives. UV–vis spectra of substrates; [1a] 0.33 M, [2a] 0.11 M. Selected works for the construction of dihydropyrido[1,2-a]indolones and current methodology. Substrate scope of the cascade reaction. Radical trapping experiment. Plausible reaction mechanism. Optimization of reaction conditions.a

Photoinduced in situ generation of DNA-targeting ligands: DNA-binding and DNA-photodamaging properties of benzo[c]quinolizinium ions

• Julika Schlosser,
• Olga Fedorova,
• Yuri Fedorov and
• Heiko Ihmels

Beilstein J. Org. Chem. 2024, 20, 101–117, doi:10.3762/bjoc.20.11

• , even under anaerobic conditions. Investigations of the mechanism of the DNA damage revealed the involvement of intermediate hydroxyl radicals and C-centered radicals. Under aerobic conditions, singlet oxygen only contributes to marginal extent to the DNA damage. Keywords: DNA intercalators

• cancer [39], and bacterial, fungal, parasitic and viral infections [40][41]. In general, PDT operates on the basis of a photosensitizer, which generates reactive intermediates upon irradiation [42][43][44][45]. Hence, in the type-I mechanism the photosensitizer induces the formation of reactive oxygen

• species (ROS), such peroxyl, alkoxy and hydroxyl radicals, or carbon-centered radicals, which subsequently induce DNA strand cleavage. In the type-II mechanism, a triplet-excited photosensitizer reacts with molecular oxygen to give highly reactive singlet oxygen, 1O2, as reactive intermediate, which in

Electron-beam-promoted fullerene dimerization in nanotubes: insights from DFT computations

• Laura Abella,
• Gerard Novell-Leruth,
• Josep M. Ricart,
• Josep M. Poblet and
• Antonio Rodríguez-Fortea

Beilstein J. Org. Chem. 2024, 20, 92–100, doi:10.3762/bjoc.20.10

• and reversible process named phase 1. We find that the barriers for the radical cation mechanism are significantly lower than those found for the neutral pathway. The peapod is mainly providing one-dimensional confinement for the reaction to take place in a more efficient way. Car–Parrinello

• -dimensional space within the CNT and compared the results with those for the same reaction in the gas phase. We assumed that the cation radical mechanism takes place, that is, the ionized CNT generates a radical cation C60•+ that reacts with a C60 molecule to yield different C120•+ dimers. The energies for

• Waals complex), so the two profiles are not that different, according to the energetic spam model by Kozuch and Shaik [20]. In any case, the mechanism via radical cation is the most favorable, both kinetically and thermodynamically. For dimer 1-D2h•+, the energy profile up to I-1 is very similar to that

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

• ) at 23 °C. Reaction of 1 with various Michael acceptors (EWG = electron-withdrawing group) forming the zwitterions 2a–i; the reactions were performed in dichloromethane at room temperature. Proposed mechanism for intramolecular proton transfer in zwitterion formation with Michael acceptors bearing a

Cycloaddition reactions of heterocyclic azides with 2-cyanoacetamidines as a new route to C,N-diheteroarylcarbamidines

• Pavel S. Silaichev,
• Tetyana V. Beryozkina,
• Vsevolod V. Melekhin,
• Valeriy O. Filimonov,
• Andrey N. Maslivets,
• Vladimir G. Ilkin,
• Wim Dehaen and
• Vasiliy A. Bakulev

Beilstein J. Org. Chem. 2024, 20, 17–24, doi:10.3762/bjoc.20.3

• the structure of the prepared compounds. To explain the outcome of the tandem reaction of 3,3-diaminoacrylonitriles to heterocyclic azides, a tentative mechanism for the formation of 1,2,3-triazoles 3 from acrylonitriles 1 and azides 2 is shown in Scheme 3. Firstly, treatment with a base, leads to

• (method A)a; 1 (0.5 mmol), 2 (0.5 mmol), NaOH (0.5 mmol), EtOH (2 mL), 0 °C → rt, 30 min (method B)b. Proposed mechanism for the formation of triazoles 3. Optimization of the reaction of amidine 1a with 6-azidopyrimidine-2,4-dione 2a.a Cytotoxicity index (IC50 ± SE) in µM of the studied compounds on human

Synthesis of N-acyl carbazoles, phenoxazines and acridines from cyclic diaryliodonium salts

• Nils Clamor,
• Mattis Damrath,
• Thomas J. Kuczmera,
• Daniel Duvinage and
• Boris J. Nachtsheim

Beilstein J. Org. Chem. 2024, 20, 12–16, doi:10.3762/bjoc.20.2

• the mechanism of opening of the iodane, we used 2,2'-diiodobiphenyl as the starting material, leading to no formation of 2a. Thus, we confirmed that our system does not activate 2,2'-diiodobiphenyl. Therefore, we applied the conditions described in Table 1, entry 7 for further investigation. With the

Identification of the p-coumaric acid biosynthetic gene cluster in Kutzneria albida: insights into the diazotization-dependent deamination pathway

• Seiji Kawai,
• Akito Yamada,
• Yohei Katsuyama and
• Yasuo Ohnishi

Beilstein J. Org. Chem. 2024, 20, 1–11, doi:10.3762/bjoc.20.1

• Information File 1). Because AvaA1 was shown not to recognize AvaA2, but to recognize AvaA3 in vitro, the homologs of these proteins (CmaA1, CmaA2, and CmaA3) are expected to have the same features. The mechanism by which AvaA1 and CmaA1 distinguish between two different ACPs (AvaA2 and AvaA3 for AvaA1 and

• strongly support our previous observation that AvaA7 showed a preference for NADPH as a cofactor [13][29]. In addition, CmaA6 could be an attractive target for understanding the reaction mechanism of ATP-dependent diazotase. CmaA6 could also be an ancestor for generating useful biocatalysts to synthesize

• -coumaric acid via diazotization-dependent deamination. The diazotase CmaA6 had a high catalytic activity, which enabled us to determine the kinetics of the denitrification reaction catalyzed by AvaA7. Furthermore, careful comparison between ava and cma clusters provided insights into (i) the mechanism of

Studying specificity in protein–glycosaminoglycan recognition with umbrella sampling

• Mateusz Marcisz,
• Sebastian Anila,
• Margrethe Gaardløs,
• Martin Zacharias and
• Sergey A. Samsonov

Beilstein J. Org. Chem. 2023, 19, 1933–1946, doi:10.3762/bjoc.19.144

• be a potential mechanism of GAG particular sequence recognition by proteins. Keywords: glycosaminoglycan; molecular docking; protein–glycosaminoglycan interaction specificity; RS-REMD; umbrella sampling; Introduction Glycosaminoglycans (GAGs) are long linear periodic anionic polydisperse

Construction of diazepine-containing spiroindolines via annulation reaction of α-halogenated N-acylhydrazones and isatin-derived MBH carbonates

• Xing Liu,
• Wenjing Shi,
• Jing Sun and
• Chao-Guo Yan

Beilstein J. Org. Chem. 2023, 19, 1923–1932, doi:10.3762/bjoc.19.143

• and proceeds through a by base-promoted annulation reaction of α-halogenated N-acylhydrazones and isatin-derived MBH carbonates. The reaction mechanism of this formal [4 + 3] annulation includes the in situ generated allylic ylide, nucleophilic substitution, Michael additon, and elimination processes

• cyclic 1,2-diazepine ring and the methylene unit is connected to the 3-positon of the oxindole moiety. On the basis of the current results and previous works [54][55][56][57][58][59][60][61], a reaction mechanism for the formation of the spiro[indoline-3,5'-[1,2]diazepines] has been proposed and is

• elimination of a proton and the Lewis base. Obviously, the spiro compounds 5 and 7 are formed by a similar reaction mechanism. Additionally, the method was applied to a gram-scale reaction of α-halogenated p-toluenesulfonylhydrazone 6c and MBH nitrile of isatin 2c under the standard conditions (Scheme 6). The

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

• aryl halides (RX) and discuss the scope and possible mechanism of these reactions. Results and Discussion Reaction of (Y-DMBI)2 with benzyl bromide We began our investigations of dehalogenation reactions using benzyl bromide (BnBr, 1a), which has a reduction peak potential (Epc) of −1.6 V vs FeCp2+/0

• electropositive metals and may be of use in more elaborate chemical transformations. Mechanism of dark reactions Doping of organic semiconductors by (Y-DMBI)2 dimers [18][39] or by various dimers formed by 18-electron sandwich compounds [18][40][41], as well as redox reactions of other dimers formed by organic

• ” mechanism, the first step is an ET reaction, resulting in the formation of D2•+, which subsequently cleaves to form D+ and D•, which is much more readily oxidized than the dimer itself and thus participates in a second fast ET (Scheme 2). In the present case, knowledge of the operative mechanism(s) is

Anion–π catalysis on carbon allotropes

• M. Ángeles Gutiérrez López,
• Mei-Ling Tan,
• Giacomo Renno,
• Augustina Jozeliūnaitė,
• J. Jonathan Nué-Martinez,
• Javier Lopez-Andarias,
• Naomi Sakai and
• Stefan Matile

Beilstein J. Org. Chem. 2023, 19, 1881–1894, doi:10.3762/bjoc.19.140

• formation (Figure 1C) [12]. This intriguing mechanism of catalysis should be further intensified on single-walled carbon nanotubes 2 (SWCNTs, Figure 1D) and multi-walled carbon nanotubes 3 (MWCNTs, Figure 1E) [13]. Multiple substrate/transition-state binding should reduce particularly in-plane polarization

• electric fields changes the mechanism of anion–π catalysis on carbon allotropes [44]. Rather than an anionic transition state creating its own catalyst, the OEEF polarizes the carbon allotrope in advance. The resulting macrodipoles then should enable strong anion–π and cation–π interactions depending on

Aromatic systems with two and three pyridine-2,6-dicarbazolyl-3,5-dicarbonitrile fragments as electron-transporting organic semiconductors exhibiting long-lived emissions

• Karolis Leitonas,
• Brigita Vigante,
• Dmytro Volyniuk,
• Audrius Bucinskas,
• Pavels Dimitrijevs,
• Sindija Lapcinska,
• Pavel Arsenyan and
• Juozas Vidas Grazulevicius

Beilstein J. Org. Chem. 2023, 19, 1867–1880, doi:10.3762/bjoc.19.139

• be soluble in common organic solvents and to exhibit non-structured emission peaks in the green-yellow color region of the spectrum. The PL intensity of the compounds in solution was enhanced after deoxygenation, indicating the presence of triplet harvesting by the mechanism of thermally activated

Controlling the reactivity of La@C₈₂ by reduction: reaction of the La@C₈₂ anion with alkyl halide with high regioselectivity

• Yutaka Maeda,
• Saeka Akita,
• Mitsuaki Suzuki,
• Michio Yamada,
• Takeshi Akasaka,
• Kaoru Kobayashi and
• Shigeru Nagase

Beilstein J. Org. Chem. 2023, 19, 1858–1866, doi:10.3762/bjoc.19.138

• produced chemically or electrochemically. C602− is a strong electron donor and potential nucleophile that reacts with electrophiles [6][7][8][9][10][11]. The mechanism for the reaction of C602− with alkyl halides has been studied in detail by Fukuzumi et al., who found that the reaction occurs via electron

• involvement of azomethine ylide; however, the detailed mechanism has not been elucidated. In this article, we describe the thermal reaction of the La@C2v-C82 anion, activated by one-electron reduction, with benzyl bromide derivatives. Results and Discussion The La@C2v-C82 anion [20] was prepared by chemical

• 3a was confirmed by the SC-XRD analysis, which showed that the addition site of addendum was indeed at the C10 position of La@C2v-C82 (Figure 5). The La@C2v-C82 anion can act as an electron donor and a nucleophile. To confirm the reaction mechanism, charge density and the p-orbital axis vector (POAV

Substituent-controlled construction of A₄B₂-hexaphyrins and A₃B-porphyrins: a mechanistic evaluation

• Seda Cinar,
• Dilek Isik Tasgin and
• Canan Unaleroglu

Beilstein J. Org. Chem. 2023, 19, 1832–1840, doi:10.3762/bjoc.19.135

• reaction mechanism of the presented method was studied on model reactions by electrospray-ionization time-of-flight (HRESI–TOF) mass spectral analysis in a timely manner. The analytical results indicated that the observed azafulvene-ended di- and tripyrrolic intermediates are responsible for the formation

Synthetic approach to 2-alkyl-4-quinolones and 2-alkyl-4-quinolone-3-carboxamides based on common β-keto amide precursors

• Yordanka Mollova-Sapundzhieva,
• Plamen Angelov,
• Danail Georgiev and
• Pavel Yanev

Beilstein J. Org. Chem. 2023, 19, 1804–1810, doi:10.3762/bjoc.19.132

• them to colonize niches and gain advantage over competitors [27][28]. Interference with this complicated communication mechanism is considered a viable strategy of combating bacterial infections and consequently a lot of research efforts have been devoted to it [29][30][31][32][33]. Many of the 4

Recent advancements in iodide/phosphine-mediated photoredox radical reactions

• Tinglan Liu,
• Yu Zhou,
• Junhong Tang and
• Chengming Wang

Beilstein J. Org. Chem. 2023, 19, 1785–1803, doi:10.3762/bjoc.19.131

• a wide range of transformations [7][8]. Moreover, they proposed a plausible mechanism for the aforementioned conversions (Scheme 2). Initially, an NaI/PPh3 complex I was formed through a cation–π interaction. Subsequently, the combination of complex I with N-(cyclohexanecarbonyloxy)phthalimide

• esters 8, 9 without the requirements of phosphine or other photocatalysts (Scheme 5). Through the use of density functional theory (DFT) calculations, they elucidated the mechanism behind this process. It was revealed that the formation of a photoactive EDA complex, which subsequently generated alkyl

• of fused ketones 34, eliminating the need for transition-metal catalysts or oxidants. The technique offered a broad substrate scope, remarkable selectivity, and simple reaction conditions. A plausible mechanism had been proposed for the photocatalytic decarboxylative [3 + 2]/[4 + 2] annulation, as

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

• ]. The use of bimetallic complexes has resulted in a favorable mechanism, increasing yields tremendously [36][37][38]. Targeting efficient completely earth-abundant metal-based systems, we have designed a novel Co(II) catalyst for the reduction of CO2 (complex 1 in Figure 1). The design aimed at a stable

• accumulation of the reduced PS− species. We propose the following mechanism (Scheme 1). The PS absorbs a photon (420 nm) and in its excited state is quenched by BIH, which is deprotonated by the base (TEA) and forms a radical (BI·). Since this radical is highly reducing, it can happen that this species can

• proposed mechanism is only tentative and should be confirmed by further analyses and theoretical calculations. In any case, the addition of proton sources should be beneficial for the CO2 pathway, and in the system, we studied so far, the only plausible proton source is the bezimidazolidine derivative

Charge carrier transport in perylene-based and pyrene-based columnar liquid crystals

• Alessandro L. Alves,
• Simone V. Bernardino,
• Carlos H. Stadtlober,
• Edivandro Girotto,
• Giliandro Farias,
• Rodney M. do Nascimento,
• Sergio F. Curcio,
• Thiago Cazati,
• Marta E. R. Dotto,
• Juliana Eccher,
• Leonardo N. Furini,
• Hugo Gallardo,
• Harald Bock and
• Ivan H. Bechtold

Beilstein J. Org. Chem. 2023, 19, 1755–1765, doi:10.3762/bjoc.19.128

• charge transport behavior. DFT calculations assisted the interpretation of electron and hole migration mechanism using the frontier orbital energies and the conjugation within the π-system. Results and Discussion The syntheses of 1 and 2 were previously published in [25] and [26], respectively. 1 is a

Effects of the aldehyde-derived ring substituent on the properties of two new bioinspired trimethoxybenzoylhydrazones: methyl vs nitro groups

• Dayanne Martins,
• Roberta Lamosa,
• Talis Uelisson da Silva,
• Carolina B. P. Ligiero,
• Sérgio de Paula Machado,
• Daphne S. Cukierman and
• Nicolás A. Rey

Beilstein J. Org. Chem. 2023, 19, 1713–1727, doi:10.3762/bjoc.19.125

• species (ROS) in vitro, which may be another mechanism through which the compound exerts its protective effects in the brain. From a drug development perspective, however, INHHQ has some pharmacological limitations, such as low solubility and certain susceptibility to hydrolysis in a water-rich medium

• absorptions lose intensity by around 10% along the first 48 hours after dilution in buffer (Figure S13 in Supporting Information File 1). The mechanism associated with the hydrolysis of N-acylhydrazones involves the protonation of the azomethine nitrogen (in this case, N1), followed by the nucleophilic attack

• , nitro and azomethine) compete for the delocalized negative charge coming from the ortho phenolate oxygen. Even though the azomethine group has a weaker deactivating effect on the ring than the nitro group, the electron density obtained by it through this mechanism increases the basicity of the N1 atom

Decarboxylative 1,3-dipolar cycloaddition of amino acids for the synthesis of heterocyclic compounds

• Xiaofeng Zhang,
• Xiaoming Ma and
• Wei Zhang

Beilstein J. Org. Chem. 2023, 19, 1677–1693, doi:10.3762/bjoc.19.123

• symmetry. The stereochemistry of the products was confirmed by X-ray crystal structure and NMR analysis. The reaction mechanism shown in Scheme 11 suggests that a semi-stabilized AMY 16 generated from the reaction of glycine and arylaldehydes undergoes a [3 + 2] cycloaddition with 14a via the favorable

• olefinic oxindoles to replace maleimides, the reactions gave spiro[indoline-tetrahydropyrrolothiazole] products 30 in 55–70% with greater than 4:1 dr [76]. The reaction mechanism suggests that the reaction of cysteine with arylaldehydes gives N,S-acetals 27 which convert to AMYs 28 after decarboxlyation

• -oriented synthesis (DOS) [82][83][84][85][86][87][88]. The work presented in this paper may also be helpful to understand the reaction mechanism and stereoselectivity of semi-stabilized N–H-type AMYs. We hope the new development for 1,3-dipolar cycloaddition chemistry can be used for the synthesis of

A deep-red fluorophore based on naphthothiadiazole as emitter with hybridized local and charge transfer and ambipolar transporting properties for electroluminescent devices

• Suangsiri Arunlimsawat,
• Patteera Funchien,
• Pongsakorn Chasing,
• Atthapon Saenubol,
• Taweesak Sudyoadsuk and
• Vinich Promarak

Beilstein J. Org. Chem. 2023, 19, 1664–1676, doi:10.3762/bjoc.19.122

• = 20%, PLQY in a thin film = 35%, and charge recombination: ηrec = 100%) to be 47%. This EUE was higher than the 25% theoretical upper limit of spin statistics for typical fluorescent emitters, indicating that the triplet excitons have been utilized via an HLCT mechanism to contribute to the EL in this

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

• previously reported for the Y = cyclohexyl, R = R' = H derivative 1e2 (1.640(4) Å) [14], despite DFT calculations indicating that the former dimer is considerably more weakly bonded [8][14] and kinetic evidence for the “cleavage-first” mechanism occurring in doping reactions using 1b2 but not 1e2 (see below

• dimer n-doping reactions that proceed via the “ET-first” mechanism (see below). In all cases the dimers are more easily oxidized, consistent with their greater air sensitivity. The impact of the Y-substituents on both 1H•+/1H and 12•+/12 potentials is not straightforward; one would expect π-conjugated

• electrochemical section; however, the observed rate constants for 1bH and 1iH suggest that 5-dimethylamino-2-thienyl affords less net charge stabilization than 4-dimethylaminophenyl. Two reaction pathways have been established for the oxidation of organometallic and organic dimers. A “cleavage-first” mechanism