Harnessing the versatility of hydrazones through electrosynthetic oxidative transformations

• Aurélie Claraz

Beilstein J. Org. Chem. 2024, 20, 1988–2004, doi:10.3762/bjoc.20.175

• -tetraethylammonium perchlorate solution under constant potential in a divided cell equipped with platinum gauze anode and nickel cathode. Such a transformation constituted a straightforward route to the corresponding fused s-triazolo perchlorates 46 in moderate to high yield. Coulometric analysis established that

• aldehyde-derived N,N-dialkylhydrazones 123 under constant current with two carbon electrodes. Aromatic and aliphatic sodium sulfinates 124 were employed as sources of sulfinate radicals under electrolyte-free reaction conditions. The targeted product was obtained in high yield regardless of the electronic

Development of a flow photochemical process for a π-Lewis acidic metal-catalyzed cyclization/radical addition sequence: in situ-generated 2-benzopyrylium as photoredox catalyst and reactive intermediate

• Masahiro Terada,
• Zen Iwasaki,
• Ryohei Yazaki,
• Shigenobu Umemiya and
• Jun Kikuchi

Beilstein J. Org. Chem. 2024, 20, 1973–1980, doi:10.3762/bjoc.20.173

• , the reaction of substrate 1c having a methyl group as a weak electron-donating group at the para-position afforded product 3c in high yield (Table 2, entry 3: 76%). In addition, the reaction of 1d having a bromo group resulted in a moderate yield, but with a significant improvement compared with the

• batch reaction (Table 2, entry 4: 57% vs 10%). The reaction of 1e substituted with a strong electron-withdrawing trifluoromethyl group afforded the product 3e in high yield (Table 2, entry 5: 77%), again confirming the high efficiency of the flow reaction system (batch: 54%). Next, the effects of the

• of the ortho-substituent (Table 2, entry 10 vs entries 3 and 7). When a fluoro group was introduced to the tethering phenyl backbone, a high yield was obtained regardless of whether it was introduced at the 6- or 7-position (Table 2, entries 11 and 12). Next, the effects of a carbonyl substituent

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 and the disappearance of vinyl protons resonances in the 1H NMR spectra [78]. Addition to the C=C bond Halogen addition: 1,2-Difluoroethylene was reported to react with chlorine [46][79] and bromine [51] under irradiation, yielding 1,2-difluoro-1,2-dihaloethanes in moderate to high yield (Scheme 9

• (trifluoromethyl)amine easily reacted with (Z)-1,2-difluoroethylene to form the addition product in high yield (Scheme 11) [89]. However, the stereochemistry of this reaction has not been reported. A similar reaction of (Z)-1,2-difluoroethylene with N-chloroimidobis(sulfonyl fluoride) (Scheme 12) [90] was shown to

• be stereounspecific, although the addition product was reported to form in high yield. In the same publication [90], it was mentioned that (FSO2)2NH did not form an addition product in the reaction with (Z)-1,2-difluoroethylene, although the reaction of (FSO2)2NH with other olefins, including

Negishi-coupling-enabled synthesis of α-heteroaryl-α-amino acid building blocks for DNA-encoded chemical library applications

• Matteo Gasparetto,
• Balázs Fődi and
• Gellért Sipos

Beilstein J. Org. Chem. 2024, 20, 1922–1932, doi:10.3762/bjoc.20.168

• acetate 2i in high yield. A similar result was obtained for the furanyl derivative 2j. Pyrazoles were the only substrate class which clearly benefited from light irradiation (2k–o), displaying not just a shorter reaction time but also higher yields. Even unprotected pyrazoles (2k, 2m, 2n) performed well

Solvent-dependent chemoselective synthesis of different isoquinolinones mediated by the hypervalent iodine(III) reagent PISA

• Ze-Nan Hu,
• Yan-Hui Wang,
• Jia-Bing Wu,
• Ze Chen,
• Dou Hong and
• Chi Zhang

Beilstein J. Org. Chem. 2024, 20, 1914–1921, doi:10.3762/bjoc.20.167

• , respectively, the substrates could be successfully converted to the products 3b–d and 2f in 52–87% yield with this method. In addition, a good or high yield of 3-methylisoquinolinones 3e–k, with different substituents on the phenyl ring, was also obtained. It is worth noting that when an electron-withdrawing

Electrochemical radical cation aza-Wacker cyclizations

• Sota Adachi and
• Yohei Okada

Beilstein J. Org. Chem. 2024, 20, 1900–1905, doi:10.3762/bjoc.20.165

• ), with platinum (Pt) as a cathode. To our delight, a constant-current condition at 1 mA was productive, and the desired five-membered pyrrolidine 2 was obtained in high yield (Table 1, entry 2). During the screening of conditions, the addition of acetonitrile (CH3CN) was found to be effective, probably

Access to 2-oxoazetidine-3-carboxylic acid derivatives via thermal microwave-assisted Wolff rearrangement of 3-diazotetramic acids in the presence of nucleophiles

• Ivan Lyutin,
• Vasilisa Krivovicheva,
• Grigory Kantin and
• Dmitry Dar’in

Beilstein J. Org. Chem. 2024, 20, 1894–1899, doi:10.3762/bjoc.20.164

• derivative 3a could be obtained in high yield (83%) after simple chromatographic separation of the reaction mixture (Scheme 2). When the synthesis was carried out using conventional heating in 1,2-dichlorobenzene (200 °C, 1 h), product 3a was obtained in slightly lower yield (75%), so further experiments

The Groebke–Blackburn–Bienaymé reaction in its maturity: innovation and improvements since its 21st birthday (2019–2023)

• Cristina Martini,
• Muhammad Idham Darussalam Mardjan and
• Andrea Basso

Beilstein J. Org. Chem. 2024, 20, 1839–1879, doi:10.3762/bjoc.20.162

• derivatization, allowed the obtainment of 18 in high yield under relatively mild conditions, and was extended to the synthesis of 23 analogues, all in high yields (>86%). The catalyst could be recovered from the reaction medium by precipitation and reused up to five times without loss in activity. In 2020, Tyagi

Chiral bifunctional sulfide-catalyzed enantioselective bromolactonizations of α- and β-substituted 5-hexenoic acids

• Sao Sumida,
• Ken Okuno,
• Taiki Mori,
• Yasuaki Furuya and
• Seiji Shirakawa

Beilstein J. Org. Chem. 2024, 20, 1794–1799, doi:10.3762/bjoc.20.158

• substrate was also examined to give a dihydroisocoumarin product 3o in high yield with moderate enantioselectivity. The absolute stereochemistry of the bromolactonization product 3o was confirmed by comparison with reported data [24]. The transformations of the optically active bromolactonization product 3a

Oxidative fluorination with Selectfluor: A convenient procedure for preparing hypervalent iodine(V) fluorides

• Samuel M. G. Dearman,
• Xiang Li,
• Yang Li,
• Kuldip Singh and
• Alison M. Stuart

Beilstein J. Org. Chem. 2024, 20, 1785–1793, doi:10.3762/bjoc.20.157

• efficient separation from the excess Selectfluor and its byproduct. Reducing the amount of Selectfluor to 2.5 equivalents and the reaction time to 24 hours (Table 2, entry 2) resulted in a similar high yield of difluoroiodane 6. The reaction also proceeded well at either room temperature for 24 hours (Table

Oxidation of benzylic alcohols to carbonyls using N-heterocyclic stabilized λ³-iodanes

• Thomas J. Kuczmera,
• Pim Puylaert and
• Boris J. Nachtsheim

Beilstein J. Org. Chem. 2024, 20, 1677–1683, doi:10.3762/bjoc.20.149

• isolated in a high yield of 84% with reisolation of the 5-(2-iodophenyl)-1H-tetrazole (6) in 90% yield. Other para-halogenated benzaldehydes 4b–f were isolated in good yields of up to 88%. ortho-Substitution led to a lower yield of the iodinated product 4g (43%) compared to the para-iodinated analogues 4d

Polymer degrading marine Microbulbifer bacteria: an un(der)utilized source of chemical and biocatalytic novelty

• Weimao Zhong and
• Vinayak Agarwal

Beilstein J. Org. Chem. 2024, 20, 1635–1651, doi:10.3762/bjoc.20.146

• 8.0 and 55 °C, respectively. The biocatalytic utility of the enzyme was also evaluated; it was used for neoagarooligosaccharide production in high yield [80]. Five additional GH-16 agarases AgaA3 produced in B. subtilis, ID2563 produced in E. coli, N3-1 produced in Pichia pastoris, AG1 produced in E

New triazinephosphonate dopants for Nafion proton exchange membranes (PEM)

• Fátima C. Teixeira,
• António P. S. Teixeira and
• C. M. Rangel

Beilstein J. Org. Chem. 2024, 20, 1623–1634, doi:10.3762/bjoc.20.145

• )methylene]bis(phosphonate) (13) [56] was successfully achieved, with high yield, by the reaction of diethyl phosphonate with 4-hydroxybenzaldehyde (12) in the presence of sodium metal. A reaction to obtain the corresponding amino derivative 14 [57] was carried out starting from 4-nitrobenzaldehyde (15

Electrocatalytic hydrogenation of cyanoarenes, nitroarenes, quinolines, and pyridines under mild conditions with a proton-exchange membrane reactor

• Koichi Mitsudo,
• Atsushi Osaki,
• Haruka Inoue,
• Eisuke Sato,
• Naoki Shida,
• Mahito Atobe and
• Seiji Suga

Beilstein J. Org. Chem. 2024, 20, 1560–1571, doi:10.3762/bjoc.20.139

• more π-extended aniline was easily obtained in a high yield. Reduction of quinolines to tetrahydroquinolines The electrochemical reduction of quinolines was performed using a PEM reactor. First, several different cathode catalyst were examined for the reduction of quinoline (6a) (Table 5). Because 4.0

• was reused eight times, and 7a was obtained in high yield in each run. The addition of pyridinium p-toluenesulfonate (PPTS) was also efficient, and MEA was repeatedly used to afford 7a in high yield (Figure 4). After further tunings, we found that the charge for electro-reduction of 6a could be

• selectively afforded the desired products. A substrate with a methoxy group at the 8-position (6o) afforded the desired product 7o in high yield. However, 6p and 6q with a methoxy group at the 6- and 3-position gave only a small amount of the target product, and 6r with a methoxy group at the 4-position gave

Transition-metal-catalyst-free electroreductive alkene hydroarylation with aryl halides under visible-light irradiation

• Kosuke Yamamoto,
• Kazuhisa Arita,
• Masami Kuriyama and
• Osamu Onomura

Beilstein J. Org. Chem. 2024, 20, 1327–1333, doi:10.3762/bjoc.20.116

• found to be suitable coupling partners. Aryl chloride 1a reacted with tert-butyl acrylate (2b) without any difficulty, providing 3ab in a high yield. Methacrylamide (2c) and acrylonitrile (2d) were transformed into the corresponding products in high yields, but with slightly lower Faradaic efficiency

Synthesis of indano[60]fullerene thioketone and its application in organic solar cells

• Yong-Chang Zhai,
• Shimon Oiwa,
• Shinobu Aoyagi,
• Shohei Ohno,
• Tsubasa Mikie,
• Jun-Zhuo Wang,
• Hirofumi Amada,
• Koki Yamanaka,
• Kazuhira Miwa,
• Naoyuki Imai,
• Takeshi Igarashi,
• Itaru Osaka and
• Yutaka Matsuo

Beilstein J. Org. Chem. 2024, 20, 1270–1277, doi:10.3762/bjoc.20.109

• converted to indano[60]fullerene thioketone (FIDS) in high yield by using Lawesson's reagent. Three compounds with different substituents in para position were successfully converted to the corresponding thioketones, showing that the reaction tolerates compounds with electron-donating and electron

Domino reactions of chromones with activated carbonyl compounds

• Peter Langer

Beilstein J. Org. Chem. 2024, 20, 1256–1269, doi:10.3762/bjoc.20.108

• dienes has to proceed with full conversion and in high yield as the they cannot be purified by chromatography. Distillation is also problematic, as dienes containing substituents located at carbon atom C-2 readily undergo isomerization reactions. The reactions of 1,3-bis(silyloxy)-1,3-butadienes with

Manganese-catalyzed C–C and C–N bond formation with alcohols via borrowing hydrogen or hydrogen auto-transfer

• Mohd Farhan Ansari,
• Atul Kumar Maurya,
• Abhishek Kumar and
• Saravanakumar Elangovan

Beilstein J. Org. Chem. 2024, 20, 1111–1166, doi:10.3762/bjoc.20.98

• , several γ-disubstituted alcohols were isolated from moderate to high yield (Scheme 48). Notably, the reduced temperature to 60 °C for 6 h is necessary to achieve the excellent yield of the desired γ-disubstituted alcohol products. To access the β-disubstituted ketones from secondary alcohols, 3 mol % of

Light on the sustainable preparation of aryl-cored dibromides

• Fabrizio Roncaglia,
• Alberto Ughetti,
• Nicola Porcelli,
• Biagio Anderlini,
• Andrea Severini and
• Luca Rigamonti

Beilstein J. Org. Chem. 2024, 20, 1076–1087, doi:10.3762/bjoc.20.95

• ” first-ring-then-benzylic halogenation methods are compared. Conclusion In summary, the peroxide-bromide halogenation method, originally developed for the monobromination of benzenoid structures, has been extended to synthesize aryl-cored polybromides with high yield and high atom economy. This method

• preparation of aryl polybromides through ring halogenation. The two variants, tested on a 10-gram scale, can be telescoped to achieve polybromo derivatives that feature both core and side chain substitution, in high yield. The application of this method enables the effective preparation of high-interest

Auxiliary strategy for the general and practical synthesis of diaryliodonium(III) salts with diverse organocarboxylate counterions

• Naoki Miyamoto,
• Daichi Koseki,
• Kohei Sumida,
• Elghareeb E. Elboray,
• Naoko Takenaga,
• Ravi Kumar and
• Toshifumi Dohi

Beilstein J. Org. Chem. 2024, 20, 1020–1028, doi:10.3762/bjoc.20.90

• smoothly under the set conditions to form the corresponding phenyl(TMP)iodonium(III) carboxylates 7aa–ad in high yield. Additionally, a range of aliphatic carboxylic acids such as acetic acid (6e), pivalic acid (6f), cyclohexanecarboxylic acid (6g), and aliphatic carboxylic acid with acidic α-proton (6h

Advancements in hydrochlorination of alkenes

• Daniel S. Müller

Beilstein J. Org. Chem. 2024, 20, 787–814, doi:10.3762/bjoc.20.72

• alkenes remains a commonly employed approach, yielding high yields for styrene derivatives (Scheme 4) [41][42][43]. The example by Theato is remarkable (Scheme 4A), who used HCl (gas) bubbled into neat alkene 13 for 5 hours, and obtained a relatively high yield of the monohydrochlorinated product 14 after

SOMOphilic alkyne vs radical-polar crossover approaches: The full story of the azido-alkynylation of alkenes

• Julien Borrel and
• Jerome Waser

Beilstein J. Org. Chem. 2024, 20, 701–713, doi:10.3762/bjoc.20.64

• high yield (72%) of the homopropargylic azide was reached. Full insights are given about the factors that were essential for the success of the optimization process. Keywords: alkyne; azide; hypervalent iodine; photoredox; trifluoroborate salt; Introduction Homopropargylic azides are important

Enhanced reactivity of Li⁺@C₆₀ toward thermal [2 + 2] cycloaddition by encapsulated Li⁺ Lewis acid

• Hiroshi Ueno,
• Yu Yamazaki,
• Hiroshi Okada,
• Fuminori Misaizu,
• Ken Kokubo and
• Hidehiro Sakurai

Beilstein J. Org. Chem. 2024, 20, 653–660, doi:10.3762/bjoc.20.58

• , resulting in much better yields of the target monoadducts. Electrochemical measurements revealed that the functionalization raised the LUMO level of Li+@C60, leading to lower reactivity for the second addition. With this facile, selective, and high-yield approach for the derivatization of ion-endohedral

A laterally-fused N-heterocyclic carbene framework from polysubstituted aminoimidazo[5,1-b]oxazol-6-ium salts

• Andrew D. Gillie,
• Matthew G. Wakeling,
• Bethan L. Greene,
• Louise Male and
• Paul W. Davies

Beilstein J. Org. Chem. 2024, 20, 621–627, doi:10.3762/bjoc.20.54

• IPrAuCl [35]. In arylative cyclisations incomplete reaction was seen with enyne 19 [8][37] but ynone 22 [39] afforded high yield of 24. A quantitative conversion was seen in the intramolecular arylative cyclisation of 25 where 13 outperformed IPrAuCl [36]. Conclusion An L-shaped NHC ligand motif, AImOx

Synthesis and biological profile of 2,3-dihydro[1,3]thiazolo[4,5-b]pyridines, a novel class of acyl-ACP thioesterase inhibitors

• Jens Frackenpohl,
• David M. Barber,
• Guido Bojack,
• Birgit Bollenbach-Wahl,
• Ralf Braun,
• Rahel Getachew,
• Sabine Hohmann,
• Kwang-Yoon Ko,
• Karoline Kurowski,
• Bernd Laber,
• Rebecca L. Mattison,
• Thomas Müller,
• Anna M. Reingruber,
• Dirk Schmutzler and
• Andrea Svejda

Beilstein J. Org. Chem. 2024, 20, 540–551, doi:10.3762/bjoc.20.46

• series. Likewise, 1,8-naphthyridines are easily accessed in high yield and on a multigram scale via Friedländer synthesis [18]. This was in clear contrast to the intermediate thiazolo[4,5-b]pyridines and the desired 2,3-dihydro[1,3]thiazolo[4,5-b]pyridine that we wanted to access, with approaches to