Quinoxaline derivatives as attractive electron-transporting materials

• Zeeshan Abid,
• Liaqat Ali,
• Sughra Gulzar,
• Faiza Wahad,
• Raja Shahid Ashraf and
• Christian B. Nielsen

Beilstein J. Org. Chem. 2023, 19, 1694–1712, doi:10.3762/bjoc.19.124

• the earlier [54]. Recently, Ding et al. prepared a novel air-stable n-type benzothiophene endcapped azaarene (BTPQ) and its sulfonated derivative (BSPQ). By introducing nitrogen atoms and sulfonyl groups, the researchers modulated the molecular energy levels and achieved the energy level requirements

Synthesis of medium and large phostams, phostones, and phostines

• Jiaxi Xu

Beilstein J. Org. Chem. 2023, 19, 687–699, doi:10.3762/bjoc.19.50

• ]thiophen-3-yl)methanol (23) and benzyl allylphosphonochlordiate (24) in the presence of triethylamine in diethyl ether via phosphonylation. It underwent a RCM reaction under the catalysis of Grubbs first generation catalyst in DCM, affording 2-(4-methylphenyl)benzothiophene-fused 2-(benzyloxy)-3,6,7,8,9,10

• -hexahydro-1,2-oxaphosphecine 2-oxide 26 in 70% yield. After the Pd-catalyzed hydrogenolysis, it was transformed to both cyclic ten-membered phostone 2-(4-methylphenyl)benzothiophene-fused 2-hydroxy-1,2-oxaphosphecane 2-oxide (27) in 40% yield and acyclic (4-(3-methyl-2-(4-methylphenyl)benzo[b]thiophen-4-yl

• . The RCM reaction was performed in the presence of Grubbs first generation catalyst in DCM, affording 2-(4-methylphenyl)benzothiophene-fused 2-(benzyloxy)-3,4,5,6,7,10-hexahydro-1,2-oxaphosphecine 2-oxide 31 in 70% yield. After hydrazine reduction and Pd-catalyzed hydrogenolysis, it was converted into

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

• previously been a challenging transformation due to the propensity of these systems to produce non-cyclized hydroarylation products due to an unproductive rhodium 1,4-migration on heteroaromatic moieties. The use of benzothiophene, benzofurans, and benzopyrrole boronate esters in this investigation prevented

Transition-metal-catalyzed C–H bond activation as a sustainable strategy for the synthesis of fluorinated molecules: an overview

• Louis Monsigny,
• Floriane Doche and
• Tatiana Besset

Beilstein J. Org. Chem. 2023, 19, 448–473, doi:10.3762/bjoc.19.35

• , respectively. This reaction was also tolerant of a 2-naphthyl group, the palladium-catalyzed trifluromethylthiolation afforded the corresponding product 8h in 76% yield. Also, the 2,4-dimethoxylated substrate 7g and the benzothiophene derivative 7i were successfully trifluoromethylthiolated in 76% and 63

Strategies to access the [5-8] bicyclic core encountered in the sesquiterpene, diterpene and sesterterpene series

• Cécile Alleman,
• Charlène Gadais,
• Laurent Legentil and
• François-Hugues Porée

Beilstein J. Org. Chem. 2023, 19, 245–281, doi:10.3762/bjoc.19.23

• the stereogenic centers formed during the cascade cyclization was secured by the use of benzothiophene-based TADDOL thiol 166 as chiral catalyst. They obtained in one single step a 5.3:1 and 3.4:1 diastereomeric ratio for C14 and C15, respectively, while forming the desired trans [5-8] ring junction

Lewis acid-catalyzed Pudovik reaction–phospha-Brook rearrangement sequence to access phosphoric esters

• Jin Yang,
• Dang-Wei Qian and
• Shang-Dong Yang

Beilstein J. Org. Chem. 2022, 18, 1188–1194, doi:10.3762/bjoc.18.123

• heterocycle, such as a benzothiophene (in 1l) or a benzofuran unit (in 1m), could smoothly be transformed into the desired products 3al and 3am, respectively, in moderate yield. Phosphinates 3an and 3ao could both be prepared under this Pudovik reaction–phospha-Brook rearrangement sequence in moderate to good

Electrochemical vicinal oxyazidation of α-arylvinyl acetates

• Yi-Lun Li,
• Zhaojiang Shi,
• Tao Shen and
• Ke-Yin Ye

Beilstein J. Org. Chem. 2022, 18, 1026–1031, doi:10.3762/bjoc.18.103

• ), chloro (16), and bromo (17), proceeded with the anticipated reactivity less efficiently (30–48% yields). The presence of other electron-withdrawing groups, such as CO2Me (18) and OCF3 (19), exhibited similar negative effects on the reaction yields. Naphthalene (20), thiophene (21), benzothiophene (22

Introducing a new 7-ring fused diindenone-dithieno[3,2-b:2',3'-d]thiophene unit as a promising component for organic semiconductor materials

• Valentin H. K. Fell,
• Joseph Cameron,
• Alexander L. Kanibolotsky,
• Eman J. Hussien and
• Peter J. Skabara

Beilstein J. Org. Chem. 2022, 18, 944–955, doi:10.3762/bjoc.18.94

• been applied in various different molecules, exhibiting outstanding performances in certain applications. The highest hole mobility for organic semiconductors was achieved for thin, crystalline films of 2,7-dioctyl[1]benzothieno[3,2-b][1]-benzothiophene (8), shown in Figure 3, achieving a maximum hole

• had sizes of ca. 100 nm, while the crystallites in films obtained by on-centre spin-coating had smaller sizes of ca. 20 nm. The same core alkylated on only one side resulted in the asymmetric 2-tridecyl[1]benzothieno[3,2-b][1]-benzothiophene (9) [28]. In polycrystalline films obtained by thermal

• . EtH-T-DI-DTT (1). Previously published, ‘bent’ diindenodithienothiophenes [16][24][25]. With crystalline films of 2,7-dioctyl[1]benzothieno[3,2-b][1]-benzothiophene (8), obtained by off-centre spin-coating, Bao et al. could obtain remarkable OFET hole mobilities of up to 43 cm2 V−1 s−1 [27]. An

α-Ketol and α-iminol rearrangements in synthetic organic and biosynthetic reactions

• Scott Benz and
• Andrew S. Murkin

Beilstein J. Org. Chem. 2021, 17, 2570–2584, doi:10.3762/bjoc.17.172

• heteroarenes were much poorer, with pyrroles and thiophenes giving yields of ≈20% or less and benzofuran and benzothiophene failing to produce any product. Interestingly, a cyclopentanone-derived substrate (120) failed to yield the corresponding α-amino cyclohexanone 121 under the standard conditions used for

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

• al. reported a Hg(II) chloride-mediated cyclization reaction of 2-alkynylphenyl alkyl sulfoxide 179 to synthesize benzothiophene derivatives 180 with good yields [114]. In this case, the reaction was believed to proceed via the initial formation of metal carbenoids followed by a sequential C–H

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

Helicene synthesis by Brønsted acid-catalyzed cycloaromatization in HFIP [(CF₃)₂CHOH]

• Takeshi Fujita,
• Noriaki Shoji,
• Nao Yoshikawa and
• Junji Ichikawa

Beilstein J. Org. Chem. 2021, 17, 396–403, doi:10.3762/bjoc.17.35

• , respectively. Furthermore, we demonstrated the synthesis of unsymmetrical thia[6]helicene 15 as a hetero[6]helicene synthesis (Scheme 6c). 3-Bromobenzothiophene 16 bearing a (1,3-dioxolan-2-yl)methyl group at the 2-position, which was readily prepared from benzothiophene, underwent Suzuki–Miyaura coupling with

Et₃N/DMSO-supported one-pot synthesis of highly fluorescent β-carboline-linked benzothiophenones via sulfur insertion and estimation of the photophysical properties

• Dharmender Singh,
• Vipin Kumar and
• Virender Singh

Beilstein J. Org. Chem. 2020, 16, 1740–1753, doi:10.3762/bjoc.16.146

• excellent light-emitting properties with quantum yields (ΦF) up to 47%. Keywords: benzothiophene; β-carboline; metal-free; photophysical properties; sulfur insertion; Introduction The pyrido[3,4-b]indole moiety, commonly referred as β-carboline, is the core unit of about one quarter of all natural

• ] which were attributed to the presence of an electrophilic as well as a nucleophilic functionality in this natural product [1]. Encouraged by the applications of β-carboline and benzothiophene motifs in medicinal and materials chemistry, it was envisaged to construct a β-carboline-based novel molecular

• hybrid containing the benzothiophene moiety (Figure 1) [57][58]. The present study was inspired by the recent findings of Nguyen and co-workers [59][60][61]. As a part of our ongoing project [62][63], we devised a simple and efficient one-pot practical approach for the construction of β-carboline

Recent synthesis of thietanes

• Jiaxi Xu

Beilstein J. Org. Chem. 2020, 16, 1357–1410, doi:10.3762/bjoc.16.116

• isobenzofuran-1-thiones 311 and 2-benzothiophene-1-thiones 314 with 2,3-dimethylbut-2-ene (215a) gave the corresponding spirothietanes 312 and 315 under photo irradiation. The spirothietanes 312 derived from 3-unsubstituted or 3-monosubstituted 1,3-dihydroisobenzofuran-1-thiones 311 were less stable and

Reaction of indoles with aromatic fluoromethyl ketones: an efficient synthesis of trifluoromethyl(indolyl)phenylmethanols using K₂CO₃/n-Bu₄PBr in water

• Thanigaimalai Pillaiyar,
• Masoud Sedaghati and
• Gregor Schnakenburg

Beilstein J. Org. Chem. 2020, 16, 778–790, doi:10.3762/bjoc.16.71

• -. 5-, 6-, and 7-azaindoles, 1g–j) provided the corresponding products in the range from 91–97% yield (3u–x). We applied the developed protocol to reactions of other heterocyclic systems such as indazole (4), benzimidazole (5), carbazole (6), benzofuran (7), and benzothiophene (8) with ketone 2a

Room-temperature Pd/Ag direct arylation enabled by a radical pathway

• Amy L. Mayhugh and
• Christine K. Luscombe

Beilstein J. Org. Chem. 2020, 16, 384–390, doi:10.3762/bjoc.16.36

• ) [11]. We hypothesized that other known palladium-catalyzed room-temperature direct arylation methods could proceed using a single electron process. Two such Pd/Ag methods were investigated: a method for benzothiophene arylation [11], and a method for fluoroarene coupling [10] (Scheme 4). First the

Combining the Ugi-azide multicomponent reaction and rhodium(III)-catalyzed annulation for the synthesis of tetrazole-isoquinolone/pyridone hybrids

• Gerardo M. Ojeda,
• Prabhat Ranjan,
• Pavel Fedoseev,
• Lisandra Amable,
• Upendra K. Sharma,
• Daniel G. Rivera and
• Erik V. Van der Eycken

Beilstein J. Org. Chem. 2019, 15, 2447–2457, doi:10.3762/bjoc.15.237

• rings, such as furan, benzofuran, pyrrole, benzopyrrole, thiophene, benzothiophene and naphthalene were also successfully synthesized (5d–l) in moderate to very good yields. The exceptions were the cases of indolopyridone 5i and thiazolopyridone 5k, the latter one could not be obtained even after many

Mono- and bithiophene-substituted diarylethene photoswitches with emissive open or closed forms

• A. Lennart Schleper,
• Mariano L. Bossi,
• Vladimir N. Belov and
• Stefan W. Hell

Beilstein J. Org. Chem. 2019, 15, 2344–2354, doi:10.3762/bjoc.15.227

• Optical Nanoscopy, Max Planck Institute for Medical Research, Jahnstrasse 29, 69120 Heidelberg, Germany 10.3762/bjoc.15.227 Abstract We present a new series of photochromic 1,2-bis(2-ethylbenzo[b]thiophen-3-yl)perfluorocyclopentenes with an oxidized benzothiophene core (O) or a nonoxidized one, decorated

• highly fluorescent “closed” forms combine photochromic and fluorescent entities in one molecule [1] and contain a perfluorocyclopentene bridge linking two 2-alkyl-1-benzothiophene-1,1-oxide residues with a C=C bond via C-3 and C-3′ atoms [2][3]. The “open” form of the DAE core (see graphical abstract and

• ” indicates oxidized benzothiophene units, and “Th1”/ “Th2” specify the number of thiophene units in the side chain. The coupling products were isolated via preparative HPLC in yields ranging from 21% to 75%. While in all cases the open forms of the diarylethenes were isolated, small amounts of SyOTh1 in its

Identification of optimal fluorescent probes for G-quadruplex nucleic acids through systematic exploration of mono- and distyryl dye libraries

• Xiao Xie,
• Michela Zuffo,
• Marie-Paule Teulade-Fichou and
• Anton Granzhan

Beilstein J. Org. Chem. 2019, 15, 1872–1889, doi:10.3762/bjoc.15.183

• be observed (I/I0 = 40 in the presence of ct DNA and 60 in the presence cl RNA; cf. Figure 6). Conversely, as mentioned above, the dyes containing benzothiophene (1w) or benzofuran (1z, 1þ) residues perform poorly as fluorescent probes. 6) Strongly aggregating dyes (i.e., 1d, 1ð, 10a and 12a

Applications of organocatalysed visible-light photoredox reactions for medicinal chemistry

• Michael K. Bogdos,
• Emmanuel Pinard and
• John A. Murphy

Beilstein J. Org. Chem. 2018, 14, 2035–2064, doi:10.3762/bjoc.14.179

• regioselectivity of unsymmetrical disubstituted alkynes was not explored. It is important to note the role of DMSO, which acts as a demethylating agent as well as solvent. Even so, the benzothiophene cores constructed by the authors are still valuable, as molecules such as 20b can be further elaborated in many

Recent advances in phosphorescent platinum complexes for organic light-emitting diodes

• Cristina Cebrián and
• Matteo Mauro

Beilstein J. Org. Chem. 2018, 14, 1459–1481, doi:10.3762/bjoc.14.124

• former, a clear impact on the emission colour was observed due to the participation of the cyclometalating unit to the HOMO frontier orbital. Thus, an emission ranging from green to yellow and finally to red was obtained going from phenyl, thiophene and benzothiophene cyclometalating rings, respectively

Fluorogenic PNA probes

• Tirayut Vilaivan

Beilstein J. Org. Chem. 2018, 14, 253–281, doi:10.3762/bjoc.14.17

• derivative. 5-Benzothiophene- and 5-benzofuran-modified uracil in aegPNA exhibited a fluorescence that was marginally sensitive to the environment [195]. When incorporated into PNA, benzothiophene-uracil exhibited an increased fluorescence compared to the free nucleoside. The opposite effect was observed

• discrimination between complementary and mismatched duplex observed with benzothiophene-uracil was limited to sequences with flanking Cs. No discrimination was observed with benzofuran-uracil PNA unless it was used in combination with GO as a quencher for ssPNA [196]. In this respect, the thiophene-modified

Photocatalytic formation of carbon–sulfur bonds

• Alexander Wimmer and
• Burkhard König

Beilstein J. Org. Chem. 2018, 14, 54–83, doi:10.3762/bjoc.14.4

• oxidation as well as the oxidation and deprotonation of the radical benzothiophene precursors are accomplished by a [CoIII] catalyst in a second catalytic cycle. [CoIII] is stepwise reduced to [CoI]. Protonation leads to a [CoIII] hydride complex generating dihydrogen by protonation. Quantitative H2

• respective sulfuranyl radical. Subsequent oxidation closes the catalytic cycle and generates a sulfur-centred cation. Finally, demethylation affords the desired substituted benzothiophene. In 2016, Yuan and co-workers developed a different synthesis of benzothiophenes (Scheme 36) [71]. They found, that a

• radical, which cyclizes to the respective sulfuranyl radical. Oxidation of this intermediate by the radical cation of the superbase closes the electron transfer cycle. Rearomatization of the benzothiophene proceeds via demethylation, accomplished by a hydroxide anion. They were able to perform the

Synthesis and photophysical properties of novel benzophospholo[3,2-b]indole derivatives

• Mio Matsumura,
• Mizuki Yamada,
• Atsuya Muranaka,
• Misae Kanai,
• Naoki Kakusawa,
• Daisuke Hashizume,
• Masanobu Uchiyama and
• Shuji Yasuike

Beilstein J. Org. Chem. 2017, 13, 2304–2309, doi:10.3762/bjoc.13.226

• knowledge, the synthesis of benzophosphole-fused indole derivatives as tetracyclic heteroacenes has not been reported. In 2015, Lu et al. reported the synthesis of only one phosphole and indole-fused pentacyclic heteroacene [35]. Recently, we reported simple and efficient synthetic routes to benzothiophene

Synthesis of benzothiophene and indole derivatives through metal-free propargyl–allene rearrangement and allyl migration

• Jinzhong Yao,
• Yajie Xie,
• Lianpeng Zhang,
• Yujin Li and
• Hongwei Zhou

Beilstein J. Org. Chem. 2017, 13, 1866–1870, doi:10.3762/bjoc.13.181

• Jinzhong Yao Yajie Xie Lianpeng Zhang Yujin Li Hongwei Zhou College of Biological, Chemical Sciences and Engineering, Jiaxing University, Jiaxing 314001, P. R. China 10.3762/bjoc.13.181 Abstract An efficient base-catalyzed protocol for the synthesis of benzothiophene is described. The reaction

• proceeds via base-promoted propargyl–allenyl rearrangement followed by cyclization and allyl migration. Phosphine-substituted indoles can be synthesized by a similar strategy. Keywords: allyl migration; benzothiophene; indole; metal-free; propargyl-allenyl; Introduction Heterocycles are frequently found

• ][14][15]. For example, the preparation of C3-borylated benzothiophene by BCl3-induced borylative cyclization of arylalkynes was recently demonstrated by Ingleson [16]. Allene-mediated cyclization reactions are advantageous due to the convenient preparation of starting materials instead of the use of