One-pot syntheses of blue-luminescent 4-aryl-1H-benzo[f]isoindole-1,3(2H)-diones by T3P^® activation of 3-arylpropiolic acids

• Melanie Denißen,
• Alexander Kraus,
• Guido J. Reiss and
• Thomas J. J. Müller

Beilstein J. Org. Chem. 2017, 13, 2340–2351, doi:10.3762/bjoc.13.231

• Düsseldorf, Universitätsstraße 1, D-40225 Düsseldorf, Germany 10.3762/bjoc.13.231 Abstract In situ activation of 3-arylpropiolic acids with T3P® (n-propylphosphonic acid anhydride) initiates a domino reaction furnishing 4-arylnaphtho[2,3-c]furan-1,3-diones in excellent yields. Upon employing these

• , sensing and display applications [41]. 4-Phenylnaphtho[2,3-c]furan-1,3-diones can well serve as reactive intermediates in multicomponent reactions, e.g., for synthesizing the corresponding imides. A particularly intriguing access to 4-phenylnaphtho[2,3-c]furan-1,3-diones is the intramolecular [4 + 2

• activation of benzyl alcohols in the synthesis of N-benzylphenothiazine derivatives [48], we reasoned that T3P® might be equally well suited for furnishing 4-phenylnaphtho[2,3-c]furan-1,3-diones, and thereby opening a straightforward entry to 4-aryl-1H-benzo[f]isoindole-1,3(2H)-diones in a diversity-oriented

Dialkyl dicyanofumarates and dicyanomaleates as versatile building blocks for synthetic organic chemistry and mechanistic studies

• Grzegorz Mlostoń and
• Heinz Heimgartner

Beilstein J. Org. Chem. 2017, 13, 2235–2251, doi:10.3762/bjoc.13.221

• radical intermediate 46 governs the formal [4 + 2]-cycloaddition reaction of E-1b with 3,4-di(α-styryl)furan (47, Scheme 15). The photoinduced reaction occurs via an electron-transfer (PET) process and led to the formation of the polycyclic product 48 in a stereospecific manner [52]. Similar products were

• (α-styryl)furan (47) with dimethyl dicyanofumarate (E-1b). Acid-catalyzed Michael addition of enolizable ketones of type 49 to E-1. Reaction of diethyl dicyanofumarate (E-1a) with ammonia NH3. Reaction of dialkyl dicyanofumarates E-1 with primary and secondary amines. Reaction of dialkyl

Switchable highly regioselective synthesis of 3,4-dihydroquinoxalin-2(1H)ones from o-phenylenediamines and aroylpyruvates

• Juraj Dobiaš,
• Marek Ondruš,
• Gabriela Addová and
• Andrej Boháč

Beilstein J. Org. Chem. 2017, 13, 1350–1360, doi:10.3762/bjoc.13.132

• -amino group of 11e. The opposite regioisomer 17e (ANTI) was selectively prepared by reaction of the more nucleophilic m-amino group of 11e with the most reactive lactonic carbonyl group in 5-(4-chlorophenyl)furan-2,3-dione (13) through an amide intermediate 15 (Scheme 2). Abasolo et al. studied the

• ) (natively preferring SYN regioselectivity, see Table 1, entry 4, column 3) complicated the desired reaction. The other possibility was to perform the regioselective synthesis of 17d (ANTI) from an appropriate furan-2,3-dione 13 (Scheme 2). The preparation of 13 failed in our hands. Therefore, we decided to

Molecular-level architectural design using benzothiadiazole-based polymers for photovoltaic applications

• Vinila N. Viswanathan,
• Arun D. Rao,
• Upendra K. Pandey,
• Arul Varman Kesavan and
• Praveen C. Ramamurthy

Beilstein J. Org. Chem. 2017, 13, 863–873, doi:10.3762/bjoc.13.87

• significant role in increasing the efficiency for OPVs [30][31]. However, fused π-bridges (such as thienothiophene) having a larger molecular structure and higher degree of conjugation are less explored with respect to thiophene and furan spacers. Thienothiophene ensures a highly delocalized electron system

Synthesis of ribavirin 2’-Me-C-nucleoside analogues

• Fanny Cosson,
• Aline Faroux,
• Jean-Pierre Baltaze,
• Jonathan Farjon,
• Régis Guillot,
• Jacques Uziel and
• Nadège Lubin-Germain

Beilstein J. Org. Chem. 2017, 13, 755–761, doi:10.3762/bjoc.13.74

• compound 10b. As depicted in Figure 3, compound 10b displayed an S-type conformation and an anti arrangement of the atoms O(1’)-C(1’)-C(1)-N(2) according to the dihedral angle of 0° lower than 90° (43°). Moreover, the benzyl group appeared to be present in two different positions covering the furan ring

Synthesis of 1-indanones with a broad range of biological activity

• Marika Turek,
• Dorota Szczęsna,
• Marek Koprowski and
• Piotr Bałczewski

Beilstein J. Org. Chem. 2017, 13, 451–494, doi:10.3762/bjoc.13.48

• followed by 1,5-hydrogen migration involving the o-alkyl substituent. 1,5-Diradicals 102 were formed as a result of elimination of acid HX from 1,4-diradicals 101. Finally, 1,5-diradicals 102 underwent cyclization to give 1-indanones 103 in good yields and 2-alkylidene benzo[c]furan derivatives 104 as

Poly(ethylene glycol)s as grinding additives in the mechanochemical preparation of highly functionalized 3,5-disubstituted hydantoins

• Andrea Mascitti,
• Massimiliano Lupacchini,
• Ruben Guerra,
• Ilya Taydakov,
• Lucia Tonucci,
• Nicola d’Alessandro,
• Frederic Lamaty,
• Jean Martinez and
• Evelina Colacino

Beilstein J. Org. Chem. 2017, 13, 19–25, doi:10.3762/bjoc.13.3

• 5c (R2 = furan-1-ylmethyl, Table 3, entries 6 and 10), and wet-grinding experiments with PEGs, for the series 2a, 3a, 4 (Table 3, entries 1, 4, and 7, respectively) and 5a (R2 = ethyl, Table 3, entry 8) or 2b and 6 (R2 = allyl , Table 3, entries 2 and 12). However, the PEG influence on the reaction

Chromium(II)-catalyzed enantioselective arylation of ketones

• Gang Wang,
• Shutao Sun,
• Ying Mao,
• Zhiyu Xie and
• Lei Liu

Beilstein J. Org. Chem. 2016, 12, 2771–2775, doi:10.3762/bjoc.12.275

• enantiocontrol, while the enantioselectivity for ketone 1e bearing an electron-donating group decreased. The mild process exhibited excellent functional group tolerance, with chloride (2f), fluoride (2g), and CF3 moieties (2h) well tolerated for further manipulation [46][47]. Heteroaryl ketones such as furan

A new paradigm for designing ring construction strategies for green organic synthesis: implications for the discovery of multicomponent reactions to build molecules containing a single ring

• John Andraos

Beilstein J. Org. Chem. 2016, 12, 2420–2442, doi:10.3762/bjoc.12.236

• target bond 3-partition dissection maps for 27 commonly found heterocyclic rings is given in the Supporting Information File 1 (see Schemes S6 to S32). These include benzimidazole, 2,3-dihydro-1H-benzo[b][1,4]diazepine, benzofuran, benzopyran, chromen-4-one, coumarin, cyclopent-2-enone, furan, Hantzsch

Superelectrophilic activation of 5-hydroxymethylfurfural and 2,5-diformylfuran: organic synthesis based on biomass-derived products

• Dmitry S. Ryabukhin,
• Dmitry N. Zakusilo,
• Mikhail O. Kompanets,
• Anton A.Tarakanov,
• Irina A. Boyarskaya,
• Tatiana O. Artamonova,
• Mikhail A. Khohodorkovskiy,
• Iosyp O. Opeida and
• Aleksander V. Vasilyev

Beilstein J. Org. Chem. 2016, 12, 2125–2135, doi:10.3762/bjoc.12.202

• (5-HMF) attracts special attention (see fundamental review from 2013 [19] and recent papers [20][21][22][23][24][25]). The high functionality and reactivity of 5-HMF, due to the presence of oxymethyl and aldehyde substituents, along with the furan moiety, allows many transformations and therefore the

• -DFF, and its participation in the hydroxyalkylation of arenes. However, furan carboxaldehydes in such reactions were studied in this work for the first time. It should be noted, that reactions of arenes with hydroxymethyl and aldehyde groups of 5-HMF and 2,5-DFF may lead to various arylmethyl- and

• on atoms C2, C3, and Ofuran upon protonation of furans 1a and 2 reveal a significant positive charge delocalization into the furan ring in species A, B, C, and D. However, from these calculations no unambiguous answer could be obtained that reveals what cations in pairs A or B, and C or D may take

New furoisocoumarins and isocoumarins from the mangrove endophytic fungus Aspergillus sp. 085242

• Ze’en Xiao,
• Senhua Chen,
• Runlin Cai,
• Shao’e Lin,
• Kui Hong and
• Zhigang She

Beilstein J. Org. Chem. 2016, 12, 2077–2085, doi:10.3762/bjoc.12.196

• features and interesting biological activities. They have been widely isolated from fungi, lichens, bacteria, plants, and insects [1][2]. Furoisocoumarins combining a furan ring and an isocoumarin moiety are divided into two subclasses depending on their fusion type: linear furo[2,3-g]isocoumarins and

• carbons at C-1' (δC 206.2) and C-2' (δC 193.9), respectively (Table 2). This evidence suggested that compound 5 lacks a furan ring and is most likely be derived from the furan ring-opening and oxidation of compound 3, which was established by HMBC correlations of the aromatic proton H-6 to C-1', two

Rearrangements of organic peroxides and related processes

• Ivan A. Yaremenko,
• Vera A. Vil’,
• Dmitry V. Demchuk and
• Alexander O. Terent’ev

Beilstein J. Org. Chem. 2016, 12, 1647–1748, doi:10.3762/bjoc.12.162

• synthesis of various heterocyclic systems, such as furan, thiophene, and pyrrole derivatives. The reaction of unsymmetrical epoxy dioxanes 290a–d with triethylamine is accompanied by the 1,2-dioxane-ring opening to form 4-hydroxy-2,3-epoxy ketones 291a–d in high yields. The base catalysis involves the

Biosynthesis of oxygen and nitrogen-containing heterocycles in polyketides

• Franziska Hemmerling and
• Frank Hahn

Beilstein J. Org. Chem. 2016, 12, 1512–1550, doi:10.3762/bjoc.12.148

• precursor and thus particular ring systems [9][10][11]. Most heterocycles in polyketides are formed by specialised PKS domains and tailoring enzymes. These can be active during assembly of the nascent PKS precursor (as for example in the case of pyran/furan formation via oxa-Michael addition, see chapters

• (f in Scheme 2). The oxidative cyclisation after C–H activation of alkyl carbons is known for the formation of furan rings 21 (g in Scheme 2). 1.1 Pyrans 1.1.1 oxa-Michael addition: The oxa-Michael addition on an α,β-unsaturated thioester intermediate leads to oxygen heterocycles along with the

• chapter 1.1.1, furan rings can also be biosynthesised via oxa-Michael additions. Nonactin. Nonactin (70) is the smallest homolog of the macrotetrolides, a family of cyclic polyethers that commonly have activity as ionophore antibiotics (Scheme 11a). It is produced by Streptomyces griseus subsp. griseus

Synthesis of ferrocenyl-substituted 1,3-dithiolanes via [3 + 2]-cycloadditions of ferrocenyl hetaryl thioketones with thiocarbonyl S-methanides

• Grzegorz Mlostoń,
• Róża Hamera-Fałdyga,
• Anthony Linden and
• Heinz Heimgartner

Beilstein J. Org. Chem. 2016, 12, 1421–1427, doi:10.3762/bjoc.12.136

• described [1]. The latter substrates were prepared efficiently via acylation of ferrocene with in situ generated mixed anhydrides containing a trifluoroacetyl unit or, alternatively, by ferrocenylation of furan, thiophene or selenophene with mixed trifluoroacetyl anhydride. The obtained ferrocenyl

Catalytic asymmetric synthesis of biologically important 3-hydroxyoxindoles: an update

• Bin Yu,
• Hui Xing,
• De-Quan Yu and
• Hong-Min Liu

Beilstein J. Org. Chem. 2016, 12, 1000–1039, doi:10.3762/bjoc.12.98

• )-catalyzed vinylogous Mukaiyama–aldol reaction between 2-(trimethylsilyloxy)furan and isatins (Scheme 35) [52]. The reactions were performed in THF at −78 °C, affording the corresponding addition products in high yields (up to 94%) and with good diastereoselectivities (the ratio of anit/syn is up to 96:4

• , the same group extended this protocol to other electron-rich aromatics such as anisole, furan, indole and aniline, generating the corresponding products in good to excellent yields (Scheme 47) [64]. This method may provide a fast entry to the 3-indolyloxindoles (also known as indol-3-ylmethanols

Syntheses of dibenzo[d,d']benzo[2,1-b:3,4-b']difuran derivatives and their application to organic field-effect transistors

• Minh Anh Truong and
• Koji Nakano

Beilstein J. Org. Chem. 2016, 12, 805–812, doi:10.3762/bjoc.12.79

• . Keywords: furan; heteroacenes; organic field-effect transistors; organic semiconductor; Introduction Organic semiconductors have significantly been developed in the past two decades by virtue of their advantages, such as low weight, flexibility, large-area processability, which are different features from

• far reported, thiophene-fused π-conjugated compounds have been widely studied as organic semiconducting materials and found to exhibit high semiconducting performances [5][13][14][15][16]. Furan-containing π-conjugated compounds have attracted less attention until recently [17][18][19][20][21][22][23

• ][24][25][26][27]. The oxygen atom possesses a smaller van der Waals radius than a sulfur atom. Accordingly, furan-containing π-conjugated compounds should be expected to form a denser packing structure in the solid state, which is one of the main requirements for high semiconducting properties [28][29

Iridium/N-heterocyclic carbene-catalyzed C–H borylation of arenes by diisopropylaminoborane

• Mamoru Tobisu,
• Takuya Igarashi and
• Naoto Chatani

Beilstein J. Org. Chem. 2016, 12, 654–661, doi:10.3762/bjoc.12.65

• a 1.1:1 mixture of 2-borylated and 2,5-diborylated products under our standard conditions (Table 2, entry 10). 2-Substituted thiophenes 14 and 15 and furan 16 were borylated successfully at the 5-positions (Table 2, entries 11–13). Electron-deficient heteroarenes such as pyridine and quinolone

Copper-mediated arylation with arylboronic acids: Facile and modular synthesis of triarylmethanes

• H. Surya Prakash Rao and
• A. Veera Bhadra Rao

Beilstein J. Org. Chem. 2016, 12, 496–504, doi:10.3762/bjoc.12.49

• towards electronic effects, the copper-mediated cross-coupling reaction is not very sensitive to steric crowding in the neighborhood of the reaction center. Next, we employed heteroaromatic boronic acids, such as furan-2-ylboronic acid (10i; Table 2, entry 8), thiophen-2-ylboronic acid (10j; Table 2

Facile synthesis of 4H-chromene derivatives via base-mediated annulation of ortho-hydroxychalcones and 2-bromoallyl sulfones

• Srinivas Thadkapally,
• Athira C. Kunjachan and
• Rajeev S. Menon

Beilstein J. Org. Chem. 2016, 12, 16–21, doi:10.3762/bjoc.12.3

• . Polycyclic aromatic hydrocarbon frameworks (naphthalene and anthracene rings) as well as a representative heterocyclic ring (furan) may be incorporated into the 4H-chromene skeleton product by using chalcones (7c, 7d, and 7e, respectively) functionalized with these moieties. Disappointingly, attempts to

Versatile synthesis and biological evaluation of novel 3’-fluorinated purine nucleosides

• Hang Ren,
• Haoyun An,
• Paul J. Hatala,
• William C. Stevens Jr,
• Jingchao Tao and
• Baicheng He

Beilstein J. Org. Chem. 2015, 11, 2509–2520, doi:10.3762/bjoc.11.272

• and Suzuki reaction conditions. To this end, 2-(tributylstannyl)furan was coupled with 6-chloropurine nucleoside 26 by Stille cross coupling [47][48] catalyzed by bis(triphenylphosphine)palladium(II) chloride in DMF (Method I) (Scheme 3). The resulting 6-aryl compound 30 was obtained in 91% yield and

• deprotected with a saturated solution of ammonia in methanol to give the desired analogue 5 with furan-2-yl substituent at position 6 of the purine base. Considering the possible toxicity of organostannyl reagents, we then utilized various organoboronic acids for Suzuki cross couplings [49][50][51] to

• and deprotection of 2,6-dichloropurine 42 was achieved with a saturated solution of ammonia in methanol to furnish 2-chloro-3’-deoxy-3’-fluoroadenosine (16). The 2,6-dichloro-intermediate 42 was coupled with 2-(tributylstannyl)furan catalyzed by bis(triphenylphosphine)palladium(II) chloride in DMF to

Molecular-oxygen-promoted Cu-catalyzed oxidative direct amidation of nonactivated carboxylic acids with azoles

• Wen Ding,
• Shaoyu Mai and
• Qiuling Song

Beilstein J. Org. Chem. 2015, 11, 2158–2165, doi:10.3762/bjoc.11.233

• conditions, providing the desired products 20 and 21 in 59% and 88% yield, respectively. Additionally, heterocyclic acids, such as thiophene- and furan-3-carboxylic acid were well tolerated, providing the amides 22 and 23 in acceptable yields. Gratifyingly, aliphatic carboxylic acids, such as

C–H bond halogenation catalyzed or mediated by copper: an overview

• Wenyan Hao and
• Yunyun Liu

Beilstein J. Org. Chem. 2015, 11, 2132–2144, doi:10.3762/bjoc.11.230

• , I) and a proper additive promoted smoothly the synthesis of various o-haloaryl-2-carboxamides 11. This synthetic protocol tolerated not only carbon aryls, but also various heteroaryls such as thiophene, furan and pyridine in the amide component. Interestingly, in an earlier example studying the

Efficient synthesis of π-conjugated molecules incorporating fluorinated phenylene units through palladium-catalyzed iterative C(sp²)–H bond arylations

• Fatiha Abdelmalek,
• Fazia Derridj,
• Safia Djebbar,
• Jean-François Soulé and
• Henri Doucet

Beilstein J. Org. Chem. 2015, 11, 2012–2020, doi:10.3762/bjoc.11.218

• palladium-catalyzed direct arylation conditions, namely the C–H bond at the ortho position to the fluorine atom and the C–H bonds at C3 or C4 positions of the (benzo)furan (Scheme 2). We decided to employ the reaction conditions that we had previously described for both direct arylations of fluorobenzenes

• [46][59][60] and C3-arylation of furans [61][62] (i.e., 2 mol % PdCl(C3H5)(dppb) as catalyst associated to KOAc as base in DMA). We were pleased to find that 2-butyl-5-(2,3,4-trifluorophenyl)furan (1) was preferentially arylated on the electron-deficient ring whichever the aryl bromide was. For

• 68% yield. Using the more challenging substrate 2-butyl-5-(2,4-difluorophenyl)furan (19) with 4-bromobenzonitrile, a mixture of three regioisomers was formed in a 61:32:7 ratio. Only the major regioisomer 27, in which the arylation happend at the C–H bond flanked by the two fluorine atoms, has been

Chiral Cu(II)-catalyzed enantioselective β-borylation of α,β-unsaturated nitriles in water

• Lei Zhu,
• Taku Kitanosono,
• Pengyu Xu and
• Shū Kobayashi

Beilstein J. Org. Chem. 2015, 11, 2007–2011, doi:10.3762/bjoc.11.217

• also reacted with the diboron reagent to give the desired products in good to high yields with good to high enantioselectivities. No significant deterioration of chiral induction was observed upon changing the electronic nature of the double bonds. Meanwhile, heterocyclic substrate 1e, bearing a furan

Stereochemistry of ring-opening/cross metathesis reactions of exo- and endo-7-oxabicyclo[2.2.1]hept-5-ene-2-carbonitriles with allyl alcohol and allyl acetate

• Piotr Wałejko,
• Michał Dąbrowski,
• Lech Szczepaniak,
• Jacek W. Morzycki and
• Stanisław Witkowski

Beilstein J. Org. Chem. 2015, 11, 1893–1901, doi:10.3762/bjoc.11.204

• reaction may be improved by using neat reaction conditions. Experimental A mixture of 1 and 2 (1.6:1) is readily available from the Diels–Alder reaction of furan and acrylonitrile according to the literature procedure [28][29]. The pure isomers were isolated by column chromatography. The 1H and 13C NMR