Synthesis of new condensed naphthoquinone, pyran and pyrimidine furancarboxylates

• Kirill A. Gomonov,
• Vasilii V. Pelipko,
• Igor A. Litvinov,
• Ilya A. Pilipenko,
• Anna M. Stepanova,
• Nikolai A. Lapatin,
• Ruslan I. Baichurin and
• Sergei V. Makarenko

Beilstein J. Org. Chem. 2025, 21, 340–347, doi:10.3762/bjoc.21.24

• case of 2e) or alcohol (in the case of 2f,g) solution for 1–3 h (ratio of acrylate/CH-acid/AcOK = 1:1:1.5) with a yield of 43–64% (Scheme 7). The structures of the obtained condensed furans 3–7 were characterized by a set of physicochemical methods, including X-ray diffraction analysis. Analysis of the

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

• , no reaction was observed with indazoles and furans using the first two conditions, requiring the formation of the ketoesters 4j and 4r first, followed by the functional group interconversion (FGI) with NH2OH·HCl (Scheme 6, blue and green sections). The Riley oxidation of the furanyl derivative 2j

2-Heteroarylethylamines in medicinal chemistry: a review of 2-phenethylamine satellite chemical space

• Carlos Nieto,
• Alejandro Manchado,
• Ángel García-González,
• David Díez and
• Narciso M. Garrido

Beilstein J. Org. Chem. 2024, 20, 1880–1893, doi:10.3762/bjoc.20.163

• rings Furans: Racemic heteroarylisopropylamines were described as MAO inhibitors (monoamine oxidase) by Vallejos et al. [14] as a natural extension of their previous QSAR studies using phenylisopropylamines [15]. The authors supported their aryl-to-heteroaryl group hopping due to the success of similar

Syntheses and medicinal chemistry of spiro heterocyclic steroids

• Laura L. Romero-Hernández,
• Ana Isabel Ahuja-Casarín,
• Penélope Merino-Montiel,
• Sara Montiel-Smith,
• José Luis Vega-Báez and
• Jesús Sandoval-Ramírez

Beilstein J. Org. Chem. 2024, 20, 1713–1745, doi:10.3762/bjoc.20.152

Domino reactions of chromones with activated carbonyl compounds

• Peter Langer

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

• -Ketoamides The reaction of 3-ketoamides 34a–f with 3-halochromones 15a–g afforded 2-(salicyloyl)furans 35a–x in mostly good to excellent yields (Scheme 18) [41]. The reaction proceeds by 1,4-addition of the methylene carbon of 34 to the chromone to give intermediate T, cyclization by regioselective

• these products can be explained by initial formation of the corresponding 2-(salicyloyl)furans V. Iodination of the latter afforded iodonium salt W which underwent cyclization by attack of the salicylate hydroxy group to give intermediate X. Extrusion of hydrogen iodide afforded the final product

A Diels–Alder probe for discovery of natural products containing furan moieties

• Alyssa S. Eggly,
• Namuunzul Otgontseren,
• Carson B. Roberts,
• Amir Y. Alwali,
• Haylie E. Hennigan and
• Elizabeth I. Parkinson

Beilstein J. Org. Chem. 2024, 20, 1001–1010, doi:10.3762/bjoc.20.88

• easily identifiable on liquid chromatography–mass spectrometry (LC–MS). The molecular probe, which undergoes this reaction with a variety of furans, was designed with both a UV-tag and a mass tag to enable easy identification. The probe has been tested with a variety of purified furans, including natural

• products, methylenomycin furan (MMF) hormones, and MMF derivatives. Moreover, the molecular probe has been tested in crude supernatants of various Streptomyces strains and enables identification of MMFs. Keywords: Diels–Alder reaction; furans; methylenomycin furan hormones; natural products; reactivity

• isolated from a sea sponge, Plakortis simplex [3][4]. Wortmannin, which also has a furan, was isolated from Penicillium wortmannin and shows anticancer activity via potent inhibition of phosphoinositide 3-kinase [5]. These are just a handful of the bioactive natural products containing furans that exist

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

• , respectively. The unsymmetrically substituted 1-(5-methylfuran-2-yl)ethan-1-one also reacted satisfactorily with 1,8-dibromonaphthalene to give acenaphtho[1,2-c]furan 18 in 53% yield. It is worth mentioning that at the present time, very few methods for the preparation of acenaphtho[1,2-c]furans have been

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

Exploring the role of halogen bonding in iodonium ylides: insights into unexpected reactivity and reaction control

• Carlee A. Montgomery and
• Graham K. Murphy

Beilstein J. Org. Chem. 2023, 19, 1171–1190, doi:10.3762/bjoc.19.86

• 44, from which reductive elimination of iodobenzene would generate 40. In 2021, Sen and Gremaud disclosed a blue LED-mediated formal C–H insertion reaction between iodonium ylides (e.g., 31) and pyrroles (e.g., 45), indoles and furans, producing malonate-substituted heterocycles 46 (Scheme 9) [126

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

Synthesis of tetrahydrofuro[3,2-c]pyridines via Pictet–Spengler reaction

• Elena Y. Mendogralo and
• Maxim G. Uchuskin

Beilstein J. Org. Chem. 2023, 19, 991–997, doi:10.3762/bjoc.19.74

• the use of 3-substituted furans. For example, the intramolecular Friedel–Crafts alkylation reaction (Scheme 1a) of alcohols [9][10][11], alkenes [12] or acetylenes [13] affords the desired tetrahydrofuro[3,2-c]pyridines. A related method is based on a Au(I)-catalyzed domino sequence dearomatization

• /ipso-cyclization/Michael-type Friedel–Crafts alkylation (Scheme 1b) [14][15][16]. Unfortunately, approaches including the intramolecular alkylation of 3-substituted furans are underinvestigated as these substrates are usually hard to reach and the resulting benzyl carbocation is often prone to undergo

• rearrangement to a more stable benzhydryl-type cation resulting in the formation of isomeric products. In an alternative group of methods, more accessible 2-substituted furans are used as starting compounds. For example, a construction of tetrahydrofuro[3,2-c]pyridines based on the Pictet–Spengler reaction [17

Aromatic C–H bond functionalization through organocatalyzed asymmetric intermolecular aza-Friedel–Crafts reaction: a recent update

• Anup Biswas

Beilstein J. Org. Chem. 2023, 19, 956–981, doi:10.3762/bjoc.19.72

• replaced by 2-substituted furans 1 as the aromatic reacting partner with imines 12 to execute the asymmetric aza-Friedel–Crafts process modulated by the chiral phosphoric acid P5 as the catalyst. A major concern of this process was the reduced aromatic character of the furan ring and the C2 methoxy

First synthesis of acylated nitrocyclopropanes

• Kento Iwai,
• Rikiya Kamidate,
• Khimiya Wada,
• Haruyasu Asahara and
• Nagatoshi Nishiwaki

Beilstein J. Org. Chem. 2023, 19, 892–900, doi:10.3762/bjoc.19.67

• benzoylacetate (3f) (Table 3, entries 1–4). The yield of aromatized furans 8 also increased with an increase in the bulkiness of the acyl group. A similar tendency was observed when adducts 4b and 4g derived from diketones 3b and 3g were reacted in the same way (Table 3, entries 5 and 6). To obtain insight into

• the two cyclization modes, the reaction of 4e was monitored by 1H NMR in 5 min intervals (Figure 1). In Figure 1, the red triangles are the total yields of furans 8e and 11e. The yields of cyclopropane 1e and furans 8e and 11e increased with increasing reaction time, without disturbing the shape of

Access to cyclopropanes with geminal trifluoromethyl and difluoromethylphosphonate groups

• Ita Hajdin,
• Romana Pajkert,
• Mira Keßler,
• Jianlin Han,
• Haibo Mei and
• Gerd-Volker Röschenthaler

Beilstein J. Org. Chem. 2023, 19, 541–549, doi:10.3762/bjoc.19.39

• obtained by the deoxofluorination of the corresponding dicarboxylic acids with sulfur tetrafluoride, thiophilic ring-opening reactions with nucleophiles or reactions of donor-substituted furans with bis(trifluoromethyl)-substituted ethylenes (Scheme 1D) [41][42][43]. The lack of application of highly

Transition-metal-catalyzed domino reactions of strained bicyclic alkenes

• Austin Pounder,
• Eric Neufeld,
• Peter Myler and
• William Tam

Beilstein J. Org. Chem. 2023, 19, 487–540, doi:10.3762/bjoc.19.38

1,4-Dithianes: attractive C2-building blocks for the synthesis of complex molecular architectures

• Bram Ryckaert,
• Ellen Demeyere,
• Frederick Degroote,
• Hilde Janssens and
• Johan M. Winne

Beilstein J. Org. Chem. 2023, 19, 115–132, doi:10.3762/bjoc.19.12

• intermolecular allyl cation-type cycloadditions (Scheme 14b–d) [103]. At first, this was investigated for its use in typical (4 + 3) cycloadditions with dienes, but mixed results were obtained (Scheme 14b). Whereas other heteroatom-stabilized allyl cations, such as oxathiins developed by Harmata, or furans

Modular synthesis of 2-furyl carbinols from 3-benzyldimethylsilylfurfural platforms relying on oxygen-assisted C–Si bond functionalization

• Sebastien Curpanen,
• Per Reichert,
• Gabriele Lupidi,
• Giovanni Poli,
• Julie Oble and
• Alejandro Perez-Luna

Beilstein J. Org. Chem. 2022, 18, 1256–1263, doi:10.3762/bjoc.18.131

• -based protocol for the catalytic C3–H silylation of furfurylimines [15]. This method allows to install a C–Si bond poised for further functionalization on the furfural unit, and thereby leads to synthetic platforms useful to access elaborated furans. This prospect was demonstrated with platforms relying

• alkoxides We first contemplated the possibility to promote C3–Si bond functionalization through intramolecular activation by alkoxides [15]. It was reported that lithium alkoxides A undergo 1,4-silyl migration (Brook rearrangement) to generate C2-lithiated furans C, which in turn can react in the presence

• to form pentavalent silicon intermediates F. Instead, the reason was probably a too low intrinsic stability of the C3-lithiated furans G, which thwarted 1,4-silyl migration. Conversely, this experiment provided evidence that cyclic siloxanes (e.g., 16), which are potential nucleophilic partners for

Direct C–H amination reactions of arenes with N-hydroxyphthalimides catalyzed by cuprous bromide

• Dongming Zhang,
• Bin Lv,
• Pan Gao,
• Xiaodong Jia and
• Yu Yuan

Beilstein J. Org. Chem. 2022, 18, 647–652, doi:10.3762/bjoc.18.65

• tested, including mono-, di-, and tri-substituted aromatics and furans, reacted with N-hydroxyphthalimide (2a) smoothly to afford good yields of the corresponding products. Anisole was well tolerated in this reaction and gave the phthalimide product 3b in 75% yield, mainly as ortho- and para-substituted

Cs₂CO₃-Promoted reaction of tertiary bromopropargylic alcohols and phenols in DMF: a novel approach to α-phenoxyketones

• Ol'ga G. Volostnykh,
• Olesya A. Shemyakina,
• Anton V. Stepanov and
• Igor' A. Ushakov

Beilstein J. Org. Chem. 2022, 18, 420–428, doi:10.3762/bjoc.18.44

• [17]. Also, M2CO3-catalyzed (M = K or Cs) addition of phenols to bromoacetylenes produced bromovinyl phenyl ethers, which were converted into 4H-chromen-4-ones, benzo[b]furans, etc. [18][19][20][21]. The latter reaction attracted our attention and prompted us to explore the interaction of phenols and

• reductive coupling of acid halides with ketones [36][37] and acetolyses of α-phenoxy-α-diazoketones [38] were also employed. Recently, F. P. Cossío et al. [39] have described a method for the preparation of benzo[b]furans by thermal heating of a dispersion of α-phenoxyketones in Al2O3. We involved the

Menadione: a platform and a target to valuable compounds synthesis

• Acácio S. de Souza,
• Ruan Carlos B. Ribeiro,
• Dora C. S. Costa,
• Fernanda P. Pauli,
• David R. Pinho,
• Matheus G. de Moraes,
• Fernando de C. da Silva,
• Luana da S. M. Forezi and
• Vitor F. Ferreira

Beilstein J. Org. Chem. 2022, 18, 381–419, doi:10.3762/bjoc.18.43

• demethoxycarbonylating annulation of methyl methacrylate (33) with 3-cyanophthalide (32), in the presence of lithium tert-butoxide as catalyst (64% yield) (Scheme 7) [91]. Recently, Dissanayake and co-workers tested the stability of furans to be used as a diene in Diels–Alder reactions for the synthesis of p

Recent developments and trends in the iron- and cobalt-catalyzed Sonogashira reactions

• Surendran Amrutha,
• Sankaran Radhika and
• Gopinathan Anilkumar

Beilstein J. Org. Chem. 2022, 18, 262–285, doi:10.3762/bjoc.18.31

• synthesized 2-arylbenzo[b]furans by intramolecular arylation and Sonogashira cross-coupling of o-iodophenol with phenylacetylene/1-substituted-2-trimethylsilylacetylene under iron(III) catalysis in the presence of 5 mol % 1,10-phenanthroline as ligand and Cs2CO3 as base (Scheme 14) [31]. The use of 1,10

• -substituted iodobenzenes catalyzed by in situ-generated α-Fe2O3 nanoparticles. One-pot synthesis of 2-arylbenzo[b]furans via tandem Sonogashira coupling–cyclization protocol. Suggested mechanism of the Fe(III) catalyzed coupling of o-iodophenol with acetylene derivatives. Fe3O4@SiO2/Schiff base/Fe(II

Recent advances and perspectives in ruthenium-catalyzed cyanation reactions

• Thaipparambil Aneeja,
• Cheriya Mukkolakkal Abdulla Afsina,
• Padinjare Veetil Saranya and
• Gopinathan Anilkumar

Beilstein J. Org. Chem. 2022, 18, 37–52, doi:10.3762/bjoc.18.4

• heteroarenes such as thiophenes, benzofurans, furans, and indoles were found suitable substrates and afforded the desired products with high chemo- and site-selectivity. A possible mechanism for the reaction was also described. The first step of the catalytic cycle involves the formation of a cationic complex

Advances in mercury(II)-salt-mediated cyclization reactions of unsaturated bonds

• Sumana Mandal,
• Raju D. Chaudhari and
• Goutam Biswas

Beilstein J. Org. Chem. 2021, 17, 2348–2376, doi:10.3762/bjoc.17.153

• frameworks from various tosylanilinoallyl acetals. 4H-Chromene derivatives were also synthesized starting from phenol derivatives (Scheme 38). Cyclization involving alkynes (-C≡C-) Marson et al. had developed the synthesis of substituted furans 133a–c promoted by catalytic use of Hg(II) salt through

• cyclization of secondary and tertiary l-alkynyl-2,3-epoxyalcohols 131a [94]. This is an example of a Hg(II)-salt-catalyzed rearrangement of 1-alkynyl-2,3-epoxy alcohols to substituted furans. The furan 133a was formed by dehydration of intermediate 132a through the corresponding oxonium cation. When R3 is an

On the application of 3d metals for C–H activation toward bioactive compounds: The key step for the synthesis of silver bullets

• Renato L. Carvalho,
• Amanda S. de Miranda,
• Mateus P. Nunes,
• Roberto S. Gomes,
• Guilherme A. M. Jardim and
• Eufrânio N. da Silva Júnior

Beilstein J. Org. Chem. 2021, 17, 1849–1938, doi:10.3762/bjoc.17.126

• behaves as a terminal oxidant to form α-aminoalkyl radicals, whereas the formation of an Fe-peroxo species in the catalytic cycle was confirmed using a combination of EPR and ESI mass spectrometry experiments (Scheme 31D). One-pot processes for the synthesis of benzo[b]furans from aryl- or alkylketones

Cascade intramolecular Prins/Friedel–Crafts cyclization for the synthesis of 4-aryltetralin-2-ols and 5-aryltetrahydro-5H-benzo[7]annulen-7-ols

• Jie Zheng,
• Shuyu Meng and
• Quanrui Wang

Beilstein J. Org. Chem. 2021, 17, 1481–1489, doi:10.3762/bjoc.17.104

• substituent as the nucleophile proceeded well to give the desired 2-hydroxy-4-aryltetralins 14aa–ae as 49:51 to 60:40 mixtures of cis/trans diastereomers in moderate to good yields. The electron-rich 5-membered heterocycles like furans and thiophene participated also smoothly in the reaction sequence, leading

• reaction leading to the 4-allyl-substituted tetrahydronaphthalen-2-ol 14ai in 65% yield. On comparing the results from the anisole-type nucleophiles or thiophene with that from furans, it was observed that the reactions with furans furnished predominantly trans-14af and trans-14ag with a high degree of