Mono or double Pd-catalyzed C–H bond functionalization for the annulative π-extension of 1,8-dibromonaphthalene: a one pot access to fluoranthene derivatives

• Nahed Ketata,
• Linhao Liu,
• Ridha Ben Salem and
• Henri Doucet

Beilstein J. Org. Chem. 2024, 20, 427–435, doi:10.3762/bjoc.20.37

• appropriate positions should enable them to be introduced regioselectively at the desired fluoranthene position, due to the greater reactivity of some of the C–H bonds in Pd-catalyzed direct arylations. First, we used 1,4-difluorobenzene under optimized reaction conditions, – i.e., 5 mol % PdCl(C3H5)(dppb

• ]thiophenes [25]. In these reactions, the C–H bonds at the C2 and C3 positions of the thienyl unit were functionalized. In order to obtain acenaphtho[1,2-c]thiophenes and related compounds that are not easily accessible [33][34][35][36][37][38], we investigated the reactivity of three 5-membered heteroarenes

• in 63% yield without cleavage of the C–Cl bond. The use of 3-substituted arylboronic acids is also possible. The reaction of 3-nitrophenylboronic acid gave product 24 in 58% yield. Access to products 25 and 26 by activating two C–H bonds is not possible due to the higher reactivity of the C–H bond

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

• mixture was heated at 50 °C. The generality of this approach was also excellent with substituted ketones, aldehydes and indoles, all forming the respective BIMs in yields ranging from 65–98% with ketones displaying the lowest reactivity, requiring up to 12 h for reaction completion. Thus, this protocol is

• to prove the generality of this protocol. Non-activated aldehydes (not bearing an electron-withdrawing group) and heteroaromatic aldehydes showed a lower reactivity and 30 mol % of catalyst 29 was required to achieve high yields (81–95%). In contrast, activated or aliphatic aldehydes afforded

• efficiency would not diminish even after 3 cycles [99]. Several substituted indoles, aldehydes and ketones reacted in good yields (74–98%), with ketones requiring longer reaction rates of 3 hours, due to their lower reactivity. The electron-donating or withdrawing effects of the substituents of the benzene

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

• Carlos R. Azpilcueta-Nicolas Jean-Philip Lumb Department of Chemistry, McGill University, 801 Sherbrooke Street West, Montreal, Quebec H3A 0B8, Canada 10.3762/bjoc.20.35 Abstract Due to their ease of preparation, stability, and diverse reactivity, N-hydroxyphthalimide (NHPI) esters have found

• of parameters with which to control reactivity. In this perspective, we provide an overview of the different mechanisms for radical reactions involving NHPI esters, with an emphasis on recent applications in radical additions, cyclizations and decarboxylative cross-coupling reactions. Within these

• , leading to their strategic incorporation as "synthons" in modern organic chemistry, with complementary reactivity to more common polar reaction manifolds [12][13][14][15]. The utility of radicals has also been expanded through the recent development of transformations involving radical-polar crossover

Synthesis of π-conjugated polycyclic compounds by late-stage extrusion of chalcogen fragments

• Aissam Okba,
• Pablo Simón Marqués,
• Kyohei Matsuo,
• Naoki Aratani,
• Hiroko Yamada,
• Gwénaël Rapenne and
• Claire Kammerer

Beilstein J. Org. Chem. 2024, 20, 287–305, doi:10.3762/bjoc.20.30

• , and this reactivity pattern was exploited as early as in the 1950s to generate in a controlled way polycyclic aromatic compounds from isolable heteropine precursors. By way of example, the phenanthrene derivative 2 was obtained by heating the dibenzo[b,f]thiepine precursor 1 in the presence of copper

• thiepine precursor 3a exhibited a mass decrease at 300 °C in agreement with the expected elimination of sulfur to yield almost quantitatively the corresponding PBI 6a. Its sulfoxide analogue 4a exhibited higher thermal reactivity, with the loss of SO identified at lower temperature (225 °C). As a proof of

• helical S- and Se-doped seco-HBCs 28b and 28c were thus obtained as racemic mixtures in three steps from dibenzoheteropines 23b and 23c in 45% and 18% overall yield, respectively. To evaluate the impact of the heteroatom oxidation state on reactivity, the sulfur and selenium oxides were next prepared via

Unveiling the regioselectivity of rhodium(I)-catalyzed [2 + 2 + 2] cycloaddition reactions for open-cage C₇₀ production

• Cristina Castanyer,
• Anna Pla-Quintana,
• Anna Roglans,
• Albert Artigas and
• Miquel Solà

Beilstein J. Org. Chem. 2024, 20, 272–279, doi:10.3762/bjoc.20.28

• to be able to produce meaningful changes in the reactivity of the cage [28][29][30][31][32]. In 2018, our group reported a catalytic process to transform C60 in bis(fulleroid) derivatives [33][34][35]. This transformation encompassed a partially intermolecular Rh-catalyzed [2 + 2 + 2] cycloaddition

Nucleophilic functionalization of thianthrenium salts under basic conditions

• Xinting Fan,
• Duo Zhang,
• Xiangchuan Xiu,
• Bin Xu,
• Yu Yuan,
• Feng Chen and
• Pan Gao

Beilstein J. Org. Chem. 2024, 20, 257–263, doi:10.3762/bjoc.20.26

• -metal-catalyzed cross-coupling [32][33] and aminofunctionalization [34] of alkenes were achieved, benefiting from the unique reactivity of organothianthrenium species that are generated through the reaction of alkenes and thianthrene sulfoxide (TT=O) or thianthrene (TT) (Scheme 1b). Alcohols are widely

Catalytic multi-step domino and one-pot reactions

• Svetlana B. Tsogoeva

Beilstein J. Org. Chem. 2024, 20, 254–256, doi:10.3762/bjoc.20.25

• of transannular cycloadditions of cycloalkenone hydrazones catalyzed by BINOL-derived phosphoric acid are reported in the Full Research Paper by Vicario, Merino, and co-workers [10]. Their methodologies can now be used to predict the reactivity of different substrates in other cycloaddition reactions

Substitution reactions in the acenaphthene analog of quino[7,8-h]quinoline and an unusual synthesis of the corresponding acenaphthylenes by tele-elimination

• Ekaterina V. Kolupaeva,
• Narek A. Dzhangiryan,
• Alexander F. Pozharskii,
• Oleg P. Demidov and
• Valery A. Ozeryanskii

Beilstein J. Org. Chem. 2024, 20, 243–253, doi:10.3762/bjoc.20.24

• make molecule 5 (and derivatives) more rigid and flat when compared to compound 3 but it will also affect its reactivity and the sites of functionalization. This work is devoted to the clarification of this circumstance with substitution and elimination reactions chosen as the key transformations. The

Metal-catalyzed coupling/carbonylative cyclizations for accessing dibenzodiazepinones: an expedient route to clozapine and other drugs

• Amina Moutayakine and
• Anthony J. Burke

Beilstein J. Org. Chem. 2024, 20, 193–204, doi:10.3762/bjoc.20.19

• . The reactivity of Co2CO8 as CO surrogate was also explored, in this case the reaction afforded the DBDAP product 4a in 55% yield (entry 6, Table 3). Molybdenum hexacarbonyl (Mo(CO)6), was shown to be a powerful CO surrogate in this carbonylative intramolecular cyclization. The efficacy of Mo(CO)6 is

Comparison of glycosyl donors: a supramer approach

• Anna V. Orlova,
• Nelly N. Malysheva,
• Maria V. Panova,
• Nikita M. Podvalnyy,
• Michael G. Medvedev and
• Leonid O. Kononov

Beilstein J. Org. Chem. 2024, 20, 181–192, doi:10.3762/bjoc.20.18

• (trifluoroacetyl vs chloroacetyl), at different concentrations (0.05 and 0.15 mol·L−1) led to mutually excluding conclusions concerning their relative reactivity and selectivity, which prevented us from revealing a possible influence of remote protective groups at O-9 on glycosylation outcome. According to the

• and straightforward as it is usually considered. Keywords: concentration; glycosylation; protecting groups; reactivity; sialic acids; stereoselectivity; Introduction Glycoconjugates containing sialic acid occur on the surface of all cell types in a variety of organisms. They participate in a broad

• critical [57][62] concentrations that separate the concentration ranges, where supramers of similar structures hence chemical properties exist, from other concentration ranges, where supramers that are organized differently and have modified chemical properties (reactivity, selectivity) are present [35

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

• such as 2d, 2e, and 2f performed well, affording the brominated product 3aa in excellent yields (90–99%). However, transformations of amide 1a to the brominated product 3aa employing unactivated alkyl bromides (2g–i) as reaction partners proceeded with low efficiency (0–53%). Notably, the reactivity of

• primary alkyl bromides is higher than that of secondary alkyl bromides, while the reactivity of tertiary alkyl bromides is the lowest (2a–c, 2g–i). Finally, dibromomethane (2j) proceeded well in the reaction, furnishing 3aa in 65% yield. As showcased in Scheme 4, this methodology is also applicable to

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

• [4][5][7]. Notably, the N,N-dimethylanilino (DMA) moiety activates the reactivity of the neighboring alkyne moiety so strongly that the [2 + 2] CA–RE reactions with electron-deficient olefins proceed seamlessly [15][16] even when the terminus of the alkyne moiety is substituted by a cyano group [17

• the DA reaction, leading to the efficient generation of the anthracenyl TCBD 19. Concerning [2 + 2] CA–RE reactions, studies have shown that alkynes exhibiting angular distortion exhibit high reactivity toward electron-deficient alkenes independent of the presence or absence of electron-donating

• substituents on the alkynes. The remarkable reactivity displayed by angle-strained alkynes makes them highly valuable tools in biorthogonal chemistry [107][108][109]. The reaction between dibenzo-fused cyclooctyne 20 and TCNE was observed to occur at room temperature, quantitatively yielding 22, wherein the

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

• reactive in chloroform solution, while in methanol the corresponding phosphonium phenolate is formed. Keywords: Lewis-base catalysis; Michael acceptor reactivity; phospha-Michael reaction; phosphonium phenolate zwitterion; Introduction Organocatalysis has emerged in recent years as a valuable and

• more accessible with methyl acrylate than with acrylonitrile. The lower reactivity of acrylamide in chloroform compared to methyl acrylate is in accordance with its lower electrophilicity. The observed rate reduction in methanol suggests the importance of the intramolecular hydrogen transfer pathway

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

• (I) source resulted in a complete collapse of reactivity. In a further experiment, we investigated the influence of iodide on the reaction to confirm whether or not diiodobiphenyl plays a role as an intermediate. The addition of potassium iodide leads to only diiodobiphenyl as the product. To confirm

• 82% yield. Next, we investigated structural variations in the cyclic iodonium salt. Due to the high reactivity of 2,4,6-trimethylbenzamide, we utilized this substrate as the nucleophile during these investigations. Scheme 3 displays the results. We started this investigation with the synthesis of

• for the 5-membered iodoliums, electron-donating groups are beneficial, while electron-withdrawing groups adversely affect their reactivity. Hence, we isolated unsubstituted and methyl-substituted N-acyl phenoxazines 3b and 3c in 84% [29] and 74% yields and their bromo and cyano variants 3d and 3e in

1-Butyl-3-methylimidazolium tetrafluoroborate as suitable solvent for BF₃: the case of alkyne hydration. Chemistry vs electrochemistry

• Marta David,
• Elisa Galli,
• Richard C. D. Brown,
• Marta Feroci,
• Fabrizio Vetica and
• Martina Bortolami

Beilstein J. Org. Chem. 2023, 19, 1966–1981, doi:10.3762/bjoc.19.147

• conditions for hydration of diphenylacetylene in BMIm-BF4 with BF3·Et2O In the initial investigation, the internal alkyne diphenylacetylene (1a) was selected as a model substrate to evaluate alkyne reactivity in the ionic liquid 1-butyl-3-methylimidazolium tetrafluoroborate (BMIm-BF4) catalysed by BF3·Et2O

• achieved with the BF4– counter anion (Table 3, entries 8–9 vs 2), suggesting PF6− and Tf2N− do not hinder the reactivity of BF3 in the hydration reaction. Based on these results, considering the higher cost of BMIm-Tf2N and BMIm-PF6, the preferred IL among those tested, in terms of both yield and cost, is

• acid, the conditions reported in entry 9 of Table 1 were chosen as reference for the study of the reactivity of different alkynes. For the internal alkyl(aryl)alkynes a regioselective hydration occurred, with the only generation of the corresponding aryl ketones, formed after the attack of water to the

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

• -toluenesulfonylhydrazones 6 have a much higher reactivity compared to that of α-halogenated benzoylsulfonylhydrazones 1 in this reaction. The desired spiro[indoline-3,5'-[1,2]diazepines] 7a–n were obtained in satisfactory yields of 58–83% and the substituents in MBH nitriles of isatins showed only marginal effects on 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

• and/or light. This may be attributable to the lower stability and greater reactivity of aryl radicals relative to that of their benzyl counterparts. Indeed, aryl radicals are known to abstract H• from THF [30][31] and presumably do so in the present reactions before any further reactions can occur

• for (Cyc-DMBI)2 is consistent with DFT estimates of bond dissociation energies for these two dimers (ΔUdiss = 163 and 210 kJ mol−1, respectively [18][44]) and with their reactivity towards TIPS-pentacene [18][39]. Impact of photoexcitation The absorptivities, ε, of (N-DMBI)2 and (Cyc-DMBI)2 at 365 nm

• ); thus, although slight overlap between the tail of substrate absorption and the tail of the output of the nominally 365 nm LED may be responsible for the reactivity seen in the absence of dimeric reductants, the stronger absorption of the two dimeric reductants examined suggests photo-acceleration of

Biphenylene-containing polycyclic conjugated compounds

• Cagatay Dengiz

Beilstein J. Org. Chem. 2023, 19, 1895–1911, doi:10.3762/bjoc.19.141

• acenes exhibit increased reactivity, readily undergoing processes of oxidation and dimerization, consequently disrupting the molecular conjugation [4]. This instability poses a significant obstacle in their widespread application across various devices [4]. The decline in stability seen in larger acenes

• = 0.07), and compound 64 displayed almost no fluorescence emission (λmax,em = 497 nm, Φem = NA). Naphthazarin–biphenylene hybrid structures Taking the advantage of naphthazarin's bifunctional Diels–Alder reactivity, Swager and his team succeeded in the synthesis of POA-type structures incorporating

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

• , University of Tsukuba, Ibaraki 305-8577, Japan Department of Theoretical Studies, Institute for Molecular Science, Okazaki 444-8585, Japan 10.3762/bjoc.19.138 Abstract Endohedral metallofullerenes have excellent redox properties, which can be used to vary their reactivity to certain classes of molecules

• and visible–near infrared spectroscopy. The reaction of La@C2v-C82 with alkyl halides using the same conditions showed no consumption of La@C2v-C82, indicating that the reactivity of La@C2v-C82 toward alkyl halides was effectively increased by one-electron reduction. Single-crystal X-ray diffraction

• , the third carbon allotrope, have unique spherical molecular structures and exhibit high reactivity as electron-deficient polyolefins. The excellent redox properties of fullerenes are useful for their chemical derivatization and practical applications [1][2][3][4][5]. Fullerene anions can be easily

N-Boc-α-diazo glutarimide as efficient reagent for assembling N-heterocycle-glutarimide diads via Rh(II)-catalyzed N–H insertion reaction

• Grigory Kantin,
• Pavel Golubev,
• Alexander Sapegin,
• Alexander Bunev and
• Dmitry Dar’in

Beilstein J. Org. Chem. 2023, 19, 1841–1848, doi:10.3762/bjoc.19.136

• scale, and enhancing the scale of the reaction did not affect the product yield (93% vs 94%). Benzimidazole displayed relatively low reactivity, resulting in moderate yield of the desired product 6j. The introduction of a chlorine atom at the 2-position of the substrate (2-chlorobenzimidazole) actively

• literature [30]. Despite the low reactivity (the reaction was carried out for 5 days with triple portion of the catalyst), the yield of the N–H insertion product involving 1,2,4-triazole was unexpectedly high (80%). Compound 6l was obtained as a single regioisomer. The reaction with tetrazoles is also

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

• advancements in the iodide/phosphine catalytic photoredox system. The primary focus of the paper is to delve into the unique catalytic reactivity exhibited by the iodide/phosphine photoredox system, while also exploring potential reaction mechanisms. It is mainly organized around different types of reactions

Trifluoromethylated hydrazones and acylhydrazones as potent nitrogen-containing fluorinated building blocks

• Zhang Dongxu

Beilstein J. Org. Chem. 2023, 19, 1741–1754, doi:10.3762/bjoc.19.127

• in various pharmaceutical and agrochemical products. This review focuses on the reactivity, synthesis, and applications of fluoromethylated hydrazones and acylhydrazones. It summarizes recent methodologies that have been used for the synthesis of various nitrogen-containing organofluorine compounds

• used as a chloride source for the preparation of these compounds [50] (Scheme 8b). As early as in 1982, the reactivity of trifluoromethylated hydrazonoyl halides in the presence of base has been systematically studied by Tanaka et al. The trifluoromethylated hydrazonoyl halides, as the precursors of

• reactions with mercaptoacetic acid and acetic anhydride leading to trifluoromethylated 1,3-thiazolidin-4-ones and 3-acetyl-2,3-dihydro-1,3,4-oxadiazoles, respectively. It was found that the C=N reactivity of the trifluoromethylated acylhydrazones is similar to that of other nitrogen-containing fluorinated

Unprecedented synthesis of a 14-membered hexaazamacrocycle

• Anastasia A. Fesenko and
• Anatoly D. Shutalev

Beilstein J. Org. Chem. 2023, 19, 1728–1740, doi:10.3762/bjoc.19.126

• structure and reactivity of the obtained macrocycle are outlined. Keywords: amidrazones; hexaazamacrocycles; pyrazolo[3,4-d]pyrimidines; ring contraction; self-assembly; Introduction The chemistry of polyazamacrocycles (PAMs) is currently one of the most rapidly developing areas of heterocyclic chemistry

• ]hexaazacyclotetradecine-4,12-diamine (5) under various conditions. Mechanistic aspects of the macrocyclization are also discussed. Some features of the structure and reactivity of the obtained macrocycle are outlined. Results and Discussion The readily available 3-amino-1-methyl-1H-pyrazole-4-carbonitrile (3) was used as

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

• . Their electrochemistry and reactivity were compared to those derived from 2-(4-(dimethylamino)phenyl)- (1b+) and 2-cyclohexylbenzo[d]imidazolium (1e+) salts. E(1+/1•) values for 2-aryl species are less reducing than for 2-alkyl analogues, i.e., the radicals are stabilized more by aryl groups than the

• strength and their reactivity with organic semiconductors (SC) does not depend solely on the SC reduction potential, since the first step, at least in many cases, is a hydride transfer rather than an electron transfer [8][9]. Moreover, as well forming the desired semiconductor radical anion SC•−, and the

• , which can be advantageous [19]. Although the impact of different 2-aryl Y groups on the reactivity of 1H species have been examined [9][24], there has been no direct comparison of the solution reactivity (or doping behavior) of 1H or 12 reductants with Y = aryl substituents to that of their Y = alkyl

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

• binding guest molecules/ions, but also to undergo unusual transformations, such as metal-induced expansion/contraction. Depending on the design of the particular hybrid, they present unique features involving intriguing redox chemistry, interesting optical properties, and reactivity towards transition

• synthesising these systems, including cyclisation reactions, self-assembly, and their remarkable reactivity. The potential applications of porphyrin-crown ether hybrids are also highlighted. Moreover, the discussion identifies the challenges associated with synthesising and characterising hybrids, outlining

• another group of hybrid macrocycles in which the dipyrrin is connected to oligo(ethylene glycol) through carbon–carbon bonds [68]. In 2022, our group demonstrated the synthesis and reactivity of crownphyrins – hybrid macrocycles wherein the dipyrrin segment links with the crown ether part through the