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

• E. M. Kosower in 1978. In this study, we report the topochemical cycloaddition of diethyl 2,6-dichloro-1,7-dioxo-1H,7H-pyrazolo[1,2-a]pyrazole-3,5-dicarboxylate (Cl2B), initiated by visible light. Crystal structure analysis confirmed that the reactive double bonds are parallel and coplanar, in line

Visible-light-promoted radical cyclisation of unactivated alkenes in benzimidazoles: synthesis of difluoromethyl- and aryldifluoromethyl-substituted polycyclic imidazoles

• Yujun Pang,
• Jinglan Yan,
• Nawaf Al-Maharik,
• Qian Zhang,
• Zeguo Fang and
• Dong Li

Beilstein J. Org. Chem. 2025, 21, 234–241, doi:10.3762/bjoc.21.15

• benzimidazole ring also successfully underwent smooth cyclization, leading to the formation of products 3c and 3d. Furthermore, the methodology was compatible with 5,6-disubstituted N-alkenylbenzimidazoles, including those with -difluoro, -dichloro, -dibromo, and -dimethyl substitutions, resulting in the

Hypervalent iodine-mediated intramolecular alkene halocyclisation

• Charu Bansal,
• Oliver Ruggles,
• Albert C. Rowett and
• Alastair J. J. Lennox

Beilstein J. Org. Chem. 2024, 20, 3113–3133, doi:10.3762/bjoc.20.258

• instead proceeded with addition of dichloro(pyridine-2-carboxylato)gold(III) complex in combination with silver triflimide, AgNTf2. A range of β-fluoroazepanes 7 were successfully synthesised with high enantiomeric purity in good yields. A mechanism for the synthesis of β-fluorinated piperidines was

5th International Symposium on Synthesis and Catalysis (ISySyCat2023)

• Anthony J. Burke and
• Elisabete P. Carreiro

Beilstein J. Org. Chem. 2024, 20, 2704–2707, doi:10.3762/bjoc.20.227

• substitution (SNAr) reaction between 2-chloro-6,7-dimethoxy-4-sulfonylquinazoline derivatives and NaN3, while the second involved an SNAr reaction between 2,4-dichloro-6,7-dimethoxyquinazoline and alkyl/arylsulfinates, followed by substitution with NaN3. Using this developed methodology, the adrenoblockers

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

• authors, the reaction proceeds via hydrogen-atom transfer (HAT) at the benzylic position, mediated by DDQ (2,3-dichloro-5,6-dicyano-1,4-benzoquinone). The proposed mechanism includes two possible pathways: In path A, the benzylic position undergoes HAT to form a benzyl radical, which is then oxidized by

Asymmetric organocatalytic synthesis of chiral homoallylic amines

• Nikolay S. Kondratyev and
• Andrei V. Malkov

Beilstein J. Org. Chem. 2024, 20, 2349–2377, doi:10.3762/bjoc.20.201

• securing the enantioselectivity of the reaction by locking the catalyst in the more active and enantioselective Z-configuration (Figure 2). Further, the authors found that H-bond donors featuring urea, thiourea, and guanidine motifs were either inactive or provided racemic mixtures. Among 3,5-dichloro

Efficacy of radical reactions of isocyanides with heteroatom radicals in organic synthesis

• Akiya Ogawa and
• Yuki Yamamoto

Beilstein J. Org. Chem. 2024, 20, 2114–2128, doi:10.3762/bjoc.20.182

• -Addition of molecular bromine to phenyl isocyanide was reported by E. Kühle et al. to afford the corresponding 1,1-adduct (PhN=CBr2) [23]. Since dichloro compounds (RN=CCl2) [24] are the imino derivatives of highly toxic phosgene (O=CCl2), reactions using them as key intermediates are not safe synthetic

1,2-Difluoroethylene (HFO-1132): synthesis and chemistry

• Liubov V. Sokolenko,
• Taras M. Sokolenko and
• Yurii L. Yagupolskii

Beilstein J. Org. Chem. 2024, 20, 1955–1966, doi:10.3762/bjoc.20.171

• -difluoroethylene was based on 1,2-dichloro-1,2-difluoroethane (HCFC-132) [48][49][50][51][52], prepared from 1,1,2,2-tetrachloro-1,2-difluoroethane (CFC-112) by reduction using lithium aluminum hydride [48][49][50][51] or photoreduction (Scheme 2) [51]. The resulting HCFC-132 reacted with zinc [47][49][52] or

• -based catalysts (Fe, Mg, Ca, Ni, Zn, Pd, Li, Na [57] or Pd, Ru [61]). Unsaturated compounds were also applied as starting materials for 1,2-difluoroethylene preparation. Thus, chlorine atoms in 1,2-dichloro-1,2-difluoroethylene (CFO-1112) could be removed through the action of hydrogen and metal

• going from diiodo- and dibromo- to dichloro- and difluoroethylene, the radius of the halogen atom decreases while the electronegativity increases. As a result, the influence of halogen atom electronegativity on the double bond is more significant in 1,2-difluoroethylene, and the relative energy of the

Regioselective quinazoline C2 modifications through the azide–tetrazole tautomeric equilibrium

• Dāgs Dāvis Līpiņš,
• Andris Jeminejs,
• Una Ušacka,
• Anatoly Mishnev,
• Māris Turks and
• Irina Novosjolova

Beilstein J. Org. Chem. 2024, 20, 675–683, doi:10.3762/bjoc.20.61

• dance process using a more electron-rich quinazoline. The commercially available 2,4-dichloro-6,7-dimethoxyquinazoline (7) was chosen for this purpose (Scheme 3). The common dimethoxy motif is also found in a variety of quinazoline-based pharmaceuticals [2][3][8][23]. We commenced our study with the

• two pathways: 1) SNAr reaction between 2-chloro-6,7-dimethoxy-4-sulfonylquinazoline derivatives and NaN3; 2) SNAr reaction between 2,4-dichloro-6,7-dimethoxyquinazoline and alkyl/arylsulfinates, followed by substitution with NaN3. 4-Azido-6,7-dimethoxy-2-alkyl/arylsulfonylquinazolines serve as

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

• -worker described the reaction of 1,8-diiodonaphthalene with arylboronic acids using PdCl2(dppf) as catalyst for the synthesis of various substituted fluoranthenes (Scheme 1a) [19]. In 2009, Quimby and Scott reported the use of 5,6-dichloro-1,2-dihydroacenaphthylene for the preparation of fluoranthene

Optimizations of lipid II synthesis: an essential glycolipid precursor in bacterial cell wall synthesis and a validated antibiotic target

• Milandip Karak,
• Cian R. Cloonan,
• Brad R. Baker,
• Rachel V. K. Cochrane and
• Stephen A. Cochrane

Beilstein J. Org. Chem. 2024, 20, 220–227, doi:10.3762/bjoc.20.22

• disaccharide synthesis alongside C6-protected acceptors (2a or 2b in Figure 2) [10][11][14][15][37][38]. More recently, an innovative one-pot glycosylation approach using a (2,6-dichloro-4-methoxyphenyl)(2,4-dichlorophenyl)-protected glycosyl acceptor has been developed, demonstrating satisfactory stability

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

• -dichloro-5,6-dicyano-1,4-benzoquinone, and its homologous compounds have been employed in chemical transformation reactions involving electron-rich alkynes. In particular, a [2 + 2] CA adduct was prepared through the [2 + 2] CA–RE reaction. Studies have shown that the thermal treatment of the [2 + 2] CA

Synthesis of ether lipids: natural compounds and analogues

• Marco Antônio G. B. Gomes,
• Alicia Bauduin,
• Chloé Le Roux,
• Romain Fouinneteau,
• Wilfried Berthe,
• Mathieu Berchel,
• Hélène Couthon and
• Paul-Alain Jaffrès

Beilstein J. Org. Chem. 2023, 19, 1299–1369, doi:10.3762/bjoc.19.96

• cesium cation with the halogen atom and the activation of the Sn–O bond of the stannylene acetal via a pentacoordinated intermediate with the fluoride anion [110]. The acetylation of the secondary alcohol and the deprotection of the primary alcohol with 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ

Non-noble metal-catalyzed cross-dehydrogenation coupling (CDC) involving ether α-C(sp³)–H to construct C–C bonds

• Hui Yu and
• Feng Xu

Beilstein J. Org. Chem. 2023, 19, 1259–1288, doi:10.3762/bjoc.19.94

• and elimination occurs to give the target coupling product. Liu et al. reported a novel In-catalyzed coupling of benzopyrans with 1,3-dicarbonyl moieties and aryl rings using dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) as the oxidant (Scheme 39) [105]. Under the established standard conditions

Selective construction of dispiro[indoline-3,2'-quinoline-3',3''-indoline] and dispiro[indoline-3,2'-pyrrole-3',3''-indoline] via three-component reaction

• Ziying Xiao,
• Fengshun Xu,
• Jing Sun and
• Chao-Guo Yan

Beilstein J. Org. Chem. 2023, 19, 1234–1242, doi:10.3762/bjoc.19.91

• solvent by rotatory evaporation at reduced pressure, the residue was subjected to column chromatography (silicon gel, 300–400 mesh) with petroleum ether and ethyl acetate (v/v = 1:1) to give the pure product for analysis. Ethyl rel-(3R,3'S,4'R)-1,1''-dibenzyl-5,5''-dichloro-7',7'-dimethyl-2,2'',5'-trioxo

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

• reductive quenching of Ru(bpy)3 and reduction of photooxidized Ru(bpy)3. Furthermore, quinones have well-studied PCET chemistry [26]. 2,3-Dichloro-5,6-cyano-1,4,hydroquinone, the hydrogenated form of 2,3-dichloro-5,6-cyano-1,4-benzoquinone (DDQ), has the highest oxidation potential of the 3 quinone examples

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

Pyridine C(sp²)–H bond functionalization under transition-metal and rare earth metal catalysis

• Haritha Sindhe,
• Malladi Mounika Reddy,
• Karthikeyan Rajkumar,
• Akshay Kamble,
• Amardeep Singh,
• Anand Kumar and
• Satyasheel Sharma

Beilstein J. Org. Chem. 2023, 19, 820–863, doi:10.3762/bjoc.19.62

• yields (Scheme 28). In this reaction, Grignard reagent 148 was used as arylation source in excess amount as the reagent underwent homocoupling leading to the formation of biaryl systems under the reaction conditions. 1,2-Dichloro-2-methylpropane (149) was found to be an effective oxidant under the

Honeycomb reactor: a promising device for streamlining aerobic oxidation under continuous-flow conditions

• Masahiro Hosoya,
• Yusuke Saito and
• Yousuke Horiuchi

Beilstein J. Org. Chem. 2023, 19, 752–763, doi:10.3762/bjoc.19.55

• Pd(OAc)2 did not dissolve in toluene even with pyridine. As a substitute for TEMPO, 2,3-dichloro-5,6-dicyano-p-benzoquinone (DDQ) was tried (Table 1, entries 9 and 10) [45]. Although the reactivity was improved compared with the TEMPO catalytic system in Table 1, entries 3–5, the DDQ catalytic system

Construction of hexabenzocoronene-based chiral nanographenes

• Ranran Li,
• Di Wang,
• Shengtao Li and
• Peng An

Beilstein J. Org. Chem. 2023, 19, 736–751, doi:10.3762/bjoc.19.54

• % yield. The Scholl reaction of compound 3 in the presence of FeCl3 and nitromethane led to the [5]helicene containing, seco-HBC-based chiral NG 4 in an 80% yield [33]. Miao and co-workers reported a twisted chiral NG 7 by a partially cyclized Scholl reaction. By treating compound 6 in 2,3-dichloro-5,6

Synthetic study toward tridachiapyrone B

• Morgan Cormier,
• Florian Hernvann and
• Michaël De Paolis

Beilstein J. Org. Chem. 2022, 18, 1741–1748, doi:10.3762/bjoc.18.183

• necessary (70% yield, 2:1 dr). The desaturation of the enone compound was next examined and while exposure of 13 to oxidant (o-iodoxybenzoic acid (IBX) or 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ)) left the starting materials unchanged, treatment with NaH in the presence of oxygen to induce the

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

• application as redox-catalysts [124][125] or photoredox catalysts [30][31] for selective oxidations and also as stoichiometric oxidants [126]. Electron-withdrawing groups are used to increase oxidative properties, the most known examples are 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) [126] and 2,3,5,6

One-pot synthesis of 2-arylated and 2-alkylated benzoxazoles and benzimidazoles based on triphenylbismuth dichloride-promoted desulfurization of thioamides

• Arisu Koyanagi,
• Yuki Murata,
• Shiori Hayakawa,
• Mio Matsumura and
• Shuji Yasuike

Beilstein J. Org. Chem. 2022, 18, 1479–1487, doi:10.3762/bjoc.18.155

• cyclodesulfurization method (Scheme 2). The reaction of methyl 4-amino-3-hydroxybenzoate (10) with 3,5-dichloro-N-phenylbenzothioamide (11) afforded the benzoxazole 12 in 91% yield. The subsequent hydrolysis of compound 12 then afforded the desired product 13 in 92% yield (84% overall). On the other hand, an attempt

Dissecting Mechanochemistry III

• Lars Borchardt and
• José G. Hernández

Beilstein J. Org. Chem. 2022, 18, 1454–1456, doi:10.3762/bjoc.18.150

• ) from an initial mechanical treatment of trichloroheptazine and Na3P, once again highlighting the importance of halogenated organic molecules as building blocks for graphitic heptazine materials (Scheme 4) [8]. Another halogenated molecule, 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ), proved to be

Mechanochemical synthesis of unsymmetrical salens for the preparation of Co–salen complexes and their evaluation as catalysts for the synthesis of α-aryloxy alcohols via asymmetric phenolic kinetic resolution of terminal epoxides

• Shengli Zuo,
• Shuxiang Zheng,
• Jianjun Liu and
• Ang Zuo

Beilstein J. Org. Chem. 2022, 18, 1416–1423, doi:10.3762/bjoc.18.147

• ethylenediamine monohydrochlorides were grinded with a half equivalent of 4-diethylamino (Et2N‒), 3,5-dichloro (Cl‒), or 3,5-di-tert-butyl (t-Bu‒) salicylaldehydes (blue moieties in Scheme 2) for 10 minutes. The synthesis of diamine monohydrochlorides and characterization data of mono-imine ammonium salts were

• ), half equivalent of 5-bromo (Br‒), 5-methyl, 4-diethylamino (Et2N‒), 3,5-dichloro (Cl‒), or 3,5-di-tert-butyl (t-Bu‒) salicylaldehydes (red moieties in Scheme 2), and trace methanol, followed by grinding for 20 minutes for the second reaction step to complete, monitored by TLC. A trace amount of

• due to the strong electron-withdrawing effect of bromine, enhancing the electrophilic property of bromo-substituted salicylaldehyde. Because of the poor solubility in the eluent, the yield of dichloro-containing 1c (88%) was lower than 1a after isolating by column chromatography. This was also found