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

A one-pot electrochemical synthesis of 2-aminothiazoles from active methylene ketones and thioureas mediated by NH₄I

• Shang-Feng Yang,
• Pei Li,
• Zi-Lin Fang,
• Sen Liang,
• Hong-Yu Tian,
• Bao-Guo Sun,
• Kun Xu and
• Cheng-Chu Zeng

Beilstein J. Org. Chem. 2022, 18, 1249–1255, doi:10.3762/bjoc.18.130

• α-halogenated dielectrophiles. Along this line, in situ α-halogenation strategies have been developed, using various halogenating reagents including Br2 [19][20], I2 [21][22], NBS [23][24][25], tribromoisocyanuric acid [26], 1,3-dichloro-5,5-dimethylhydantoin [27], HBr or HI, DMSO [28] etc. (Scheme

Derivatives of benzo-1,4-thiazine-3-carboxylic acid and the corresponding amino acid conjugates

• Péter Kisszékelyi,
• Tibor Peňaška,
• Klára Stankovianska,
• Mária Mečiarová and
• Radovan Šebesta

Beilstein J. Org. Chem. 2022, 18, 1195–1202, doi:10.3762/bjoc.18.124

• . The use of 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) in 1,4-dioxane afforded the dimer 11a in a slightly better yield of 46% (Scheme 2). For all the prepared benzothiazine derivatives 10 we observed some degree of instability. The derivatives were reasonably stable in the solid state but usually

DDQ in mechanochemical C–N coupling reactions

• Shyamal Kanti Bera,
• Rosalin Bhanja and
• Prasenjit Mal

Beilstein J. Org. Chem. 2022, 18, 639–646, doi:10.3762/bjoc.18.64

• -Dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) is a commonly known oxidant. Herein, we report that DDQ can be used to synthesize 1,2-disubstituted benzimidazoles and quinazolin-4(3H)-ones via the intra- and intermolecular C–N coupling reaction under solvent-free mechanochemical (ball milling) conditions. In

• moiety in 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ), it was well established as a hydride transfer reagent in various organic reactions [14][15]. Generally, DDQ assists in dehydrogenation reactions in organic synthesis [16]. In this context, various carbon–heteroatom bond formation reactions such

• ) and naphthyl (2f) proved to be efficient. Similarly, the 5,6-dimethyl- or 5,6-dichloro-1,2-disubstituted benzimidazoles 2i, 2j, and 2k were synthesized with 82, 85, and 79% yield, respectively. In addition, the structure of the synthesized 2-(4-(phenylethynyl)phenyl)-substituted product 2h was

Substituent effect on TADF properties of 2-modified 4,6-bis(3,6-di-tert-butyl-9-carbazolyl)-5-methylpyrimidines

• Irina Fiodorova,
• Tomas Serevičius,
• Rokas Skaisgiris,
• Saulius Juršėnas and
• Sigitas Tumkevicius

Beilstein J. Org. Chem. 2022, 18, 497–507, doi:10.3762/bjoc.18.52

• -9H-carbazol-9-yl)-5-methyl-2-methylthiopyrimidine (tCbz-mPYR) as a starting material for the synthesis of 2-substituted pyrimidine emitters (Scheme 1). Compound tCbz-mPYR was synthesized by using the palladium-catalyzed Buchwald–Hartwig amination reaction of 4,6-dichloro-5-methyl-2-methylpyrimidine

Recent advances in the asymmetric phosphoric acid-catalyzed synthesis of axially chiral compounds

• Alemayehu Gashaw Woldegiorgis and
• Xufeng Lin

Beilstein J. Org. Chem. 2021, 17, 2729–2764, doi:10.3762/bjoc.17.185

• accelerating imine formation (I-19), and under the catalysis of a chiral phosphoric acid, intramolecular nucleophilic addition occurs to form I-20, followed by oxidative dehydrogenation with 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ). In the presence of 10 mol % chiral phosphoric acid CPA 7, the axially

Synthetic strategies toward 1,3-oxathiolane nucleoside analogues

• Umesh P. Aher,
• Dhananjai Srivastava,
• Girij P. Singh and
• Jayashree B. S

Beilstein J. Org. Chem. 2021, 17, 2680–2715, doi:10.3762/bjoc.17.182

• chlorination at the α-position of the ester. The dichloro-substituted intermediate 3k was further cyclized to produce the oxathiolane 56a by reaction with water in the presence of acetonitrile as solvent. The focus of this novel route was to access basic reagents that are useful for the synthesis of 3TC (1

Electrocatalytic C(sp³)–H/C(sp)–H cross-coupling in continuous flow through TEMPO/copper relay catalysis

• Bin Guo and
• Hai-Chao Xu

Beilstein J. Org. Chem. 2021, 17, 2650–2656, doi:10.3762/bjoc.17.178

• electrochemical microreactors can be a viable tool for developing efficient transition-metal electrocatalysis. C(sp3)–H alkynylation of tetrahydroisoquinolines. L* = chiral ligand. TEMPO = 2,2,6,6-tetramethylpiperidine 1-oxyl. DDQ = 2,3-dichloro-5,6-dicyano-1,4-benzoquinone. BPO = benzoyl peroxide. Substrate

Development of N-F fluorinating agents and their fluorinations: Historical perspective

• Teruo Umemoto,
• Yuhao Yang and
• Gerald B. Hammond

Beilstein J. Org. Chem. 2021, 17, 1752–1813, doi:10.3762/bjoc.17.123

• -dichlorocamphorsultam) 17-2 [75] (Scheme 37). The maximum enantioselectivity of enolates of β-ketoesters with (−)-9-1 or (+)-9-2, first prepared by Lang in 1988 (see section 1-9), was 70% ee. The asymmetric fluorination with (+)- or (−)-17-2 afforded up to 75% ee as indicated in Scheme 38. The dichloro reagent 17-2

Double-headed nucleosides: Synthesis and applications

• Vineet Verma,
• Jyotirmoy Maity,
• Vipin K. Maikhuri,
• Ritika Sharma,
• Himal K. Ganguly and
• Ashok K. Prasad

Beilstein J. Org. Chem. 2021, 17, 1392–1439, doi:10.3762/bjoc.17.98

• nucleosides 2,6-dichloro-9-(2,3,5-tri-O-acetyl-5-C-(3-mesitylisoxazol-5-yl)-α-ʟ-idopentofuranosyl)-9H-purine (91) and 2,6-dichloro-9-(2,3,5-tri-O-acetyl-5-C-(1-phenyl-1,2,3-triazol-4-yl)-β-ᴅ-glucopentofuranosyl)-9H-purine (92) starting from 3,5-di-O-acetyl-6,7-dideoxy-1,2-O-isopropylidene-ʟ-ido/α-ᴅ-gluco-hept

Application of the Meerwein reaction of 1,4-benzoquinone to a metal-free synthesis of benzofuropyridine analogues

• Rashmi Singh,
• Tomas Horsten,
• Rashmi Prakash,
• Swapan Dey and
• Wim Dehaen

Beilstein J. Org. Chem. 2021, 17, 977–982, doi:10.3762/bjoc.17.79

• converted to novel oxazole-fused derivatives 19 and 20, respectively, by condensation with benzaldehyde and subsequent 2,3-dichloro-5.6-dicyano-p-benzoquinone (DDQ)-mediated oxidation (Scheme 3). Aldehyde building block 16 was a versatile starting material for further cyclization reactions. Synthesis of

Unexpected rearrangements and a novel synthesis of 1,1-dichloro-1-alkenones from 1,1,1-trifluoroalkanones with aluminium trichloride

• Beatrice Lansbergen,
• Catherine S. Meister and
• Michael C. McLeod

Beilstein J. Org. Chem. 2021, 17, 404–409, doi:10.3762/bjoc.17.36

• of 1,1-dichloro-1-alkenones. The reaction scope was found to be broad, with various chain lengths and aryl substituents tolerated. For substrates containing an electron-rich aromatic ring, further reactions take place, resulting in bicyclic and/or rearrangement products. Keywords: aluminium

• trichloride; dichloroalkenes; Friedel–Crafts alkylation; rearrangement; trifluoroalkanes; Introduction 1,1-Dichloro-1-alkenes are valuable synthetic intermediates and have been employed in Pd-mediated cross couplings of one or both chlorine atoms [1][2][3][4][5][6][7], carbonylation reactions [8], and C–H

• bond alkynylations of heteroarenes [9]. The 1,1-dichloro-1-alkenyl moiety is found in a number of pyrethroid insecticides including permethrin and marine natural products such as caracolamide A [10] (Figure 1). 1,1-Dichloro-1-alkenes 2 are commonly prepared from the corresponding aldehydes 1 in one

Annulation of a 1,3-dithiole ring to a sterically hindered o-quinone core. Novel ditopic redox-active ligands

• Sergey V. Norkov,
• Anton V. Cherkasov,
• Andrey S. Shavyrin,
• Maxim V. Arsenyev,
• Viacheslav A. Kuropatov and
• Vladimir K. Cherkasov

Beilstein J. Org. Chem. 2021, 17, 273–282, doi:10.3762/bjoc.17.26

• reaction of 4,5-dichloro-3,6-di-tert-butyl-o-benzoquinone (4) [19] with alkali metal gem-dithiolates. This synthetic procedure allows us to significantly extend the range of substituents which could be potentially introduced to the final product. Gem-dithiolates are comparatively less studied than related

The preparation and properties of 1,1-difluorocyclopropane derivatives

• Kymbat S. Adekenova,
• Peter B. Wyatt and
• Sergazy M. Adekenov

Beilstein J. Org. Chem. 2021, 17, 245–272, doi:10.3762/bjoc.17.25

• isomerization of trans-1,2-dichloro-3,3-difluorocyclopropane (84) (Scheme 37) [82]. Further research in this area was performed by the groups of Jefford [83] and Dolbier [84], who studied the 1,1-difluoro-2,3-dimethylcyclopropanes 86 and 87 (Scheme 38). Dolbier found that geminal fluorine substituents lowered

1,2,3-Triazoles as leaving groups in S_NAr–Arbuzov reactions: synthesis of C6-phosphonated purine derivatives

• Kārlis-Ēriks Kriķis,
• Irina Novosjolova,
• Anatoly Mishnev and
• Māris Turks

Beilstein J. Org. Chem. 2021, 17, 193–202, doi:10.3762/bjoc.17.19

• procedure for the SNAr–Arbuzov reaction: synthesis of 9-alkyl-2-chloro-9H-purine C6-phosphonates 2 Diethyl (2-chloro-9-heptyl-9H-purin-6-yl)phosphonate (2a): 2,6-Dichloro-9-heptyl-9H-purine (1, 1.03 g, 3.59 mmol, 1.0 equiv) was dissolved in P(OEt)3 (12 mL) and stirred for 3 h at 160 °C (HPLC control). Then

Three-component reactions of aromatic amines, 1,3-dicarbonyl compounds, and α-bromoacetaldehyde acetal to access N-(hetero)aryl-4,5-unsubstituted pyrroles

• Wenbo Huang,
• Kaimei Wang,
• Ping Liu,
• Minghao Li,
• Shaoyong Ke and
• Yanlong Gu

Beilstein J. Org. Chem. 2020, 16, 2920–2928, doi:10.3762/bjoc.16.241

• obtained for 4o and 4p were slightly inferior. Gratifyingly, a 3,5-dichloro-4-(1,1,2,2-tetrafluoroethoxy)aniline also participated smoothly in this reaction, and the expected product 4q can be obtained in 75% yield. This fluorinated substituent on the aniline ring has been identified as the key precursor

A new method for the synthesis of diamantane by hydroisomerization of binor-S on treatment with sulfuric acid

• Rishat I. Aminov and
• Ravil I. Khusnutdinov

Beilstein J. Org. Chem. 2020, 16, 2534–2539, doi:10.3762/bjoc.16.205

• starting binor-S (2) being recovered unchanged. The reaction of hydrocarbon 2 with hydrochloric acid proceeds with the addition of HCl to the cyclopropane ring and results in the formation of a mixture of mono- and dichloro derivatives, the synthesis of which has been reported [13][14]. When sulfuric acid