Cerium-photocatalyzed aerobic oxidation of benzylic alcohols to aldehydes and ketones

• Girish Suresh Yedase,
• Sumit Kumar,
• Jessica Stahl,
• Burkhard König and
• Veera Reddy Yatham

Beilstein J. Org. Chem. 2021, 17, 1727–1732, doi:10.3762/bjoc.17.121

• -dichlorobenzaldehyde (2w) in 70% yield. The sulfur-containing compounds 4-(phenylthio)benzyl alcohol (1r) and the heterocyclic compound thiophene-2-ylmethanol (1x) gave the corresponding aldehydes 2r and 2x in 61 and 80% yield, respectively. Finally, 2-naphthylmethanol (1y) was subjected to the reaction conditions and

A recent overview on the synthesis of 1,4,5-trisubstituted 1,2,3-triazoles

• Pezhman Shiri,
• Ali Mohammad Amani and
• Thomas Mayer-Gall

Beilstein J. Org. Chem. 2021, 17, 1600–1628, doi:10.3762/bjoc.17.114

• at room temperature. First, several nonactivated arylalkynes containing electron-rich and electron-deficient groups as well as thiophene derivatives afforded the desired 5-arylated triazole derivatives. Then, the diversity of arylboronic acids was explored. The arylboronic acids containing some

Recent advances in the application of isoindigo derivatives in materials chemistry

• Andrei V. Bogdanov and
• Vladimir F. Mironov

Beilstein J. Org. Chem. 2021, 17, 1533–1564, doi:10.3762/bjoc.17.111

• platform (in position 1 and in the aromatic ring) and in the side chain. In the overwhelming majority of works, studies on the photophysical properties of isoindigo derivatives containing a thiophene fragment in position 6 are described. Thus, the authors of References [14][15] obtained a small number of

• derivatives is based on the Suzuki reaction. At the same time, pyrene-1-ylboronic acid and 6,6'-dibromoisoindigo were used to introduce a pyrene fragment directly into the isoindigo nucleus, and to obtain a thiophene analogue, pyrenyl-substituted 2-bromothiophene and 6,6'-bis(4,4,5,5-tetramethyl-1,3,2

• -dioxaborolan-2-yl)isoindigo were used (Scheme 6). Thus, a photovoltaic cell based on thiophene derivative 7 mixed with PC71BM showed an efficiency of 1.88% [19], but if the pyrenyl substituent is bonded directly to the isoindigo core, the efficiency of such an OSC turns out to be significantly lower (0.10

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

Iodine-catalyzed electrophilic substitution of indoles: Synthesis of (un)symmetrical diindolylmethanes with a quaternary carbon center

• Thanigaimalai Pillaiyar,
• Masoud Sedaghati,
• Andhika B. Mahardhika,
• Lukas L. Wendt and
• Christa E. Müller

Beilstein J. Org. Chem. 2021, 17, 1464–1475, doi:10.3762/bjoc.17.102

• phenyl ring of 1 was replaced by the heteroaryl moiety thiophene (1i), reacted efficiently with a series of indole derivatives (2a, 2d, 2h) providing yields of 82–90% (3v–x). We further extended this protocol to the preparation of unsymmetrical pentafluoroethylated and heptafluoropropylated DIM

Synthetic reactions driven by electron-donor–acceptor (EDA) complexes

• Zhonglie Yang,
• Yutong Liu,
• Kun Cao,
• Xiaobin Zhang,
• Hezhong Jiang and
• Jiahong Li

Beilstein J. Org. Chem. 2021, 17, 771–799, doi:10.3762/bjoc.17.67

• additive to give corresponding thiophene radical 76 and aniline radical cation under irradiation with light. Then, 76 reacted with 73, giving rise to corresponding radical 77. Finally, product 74 was given via hydrogen atom transfer (Scheme 26). In contrast to (hetero)aryl halides with indispensable

Synthesis of trifluoromethyl ketones by nucleophilic trifluoromethylation of esters under a fluoroform/KHMDS/triglyme system

• Yamato Fujihira,
• Yumeng Liang,
• Makoto Ono,
• Kazuki Hirano,
• Takumi Kagawa and
• Norio Shibata

Beilstein J. Org. Chem. 2021, 17, 431–438, doi:10.3762/bjoc.17.39

• effect on the yield of the reaction of 1g (Table 2, entries 3–6, 58–72%). Next, a range of common oxygen and sulfur-containing compounds such as furan, tetrahydrofuran, 1,4-dioxane, thiophene, benzo[b]thiophene, dibenzo[b,d]thiophene, and diphenylsulfane were also screened. These substances also have

CF₃-substituted carbocations: underexploited intermediates with great potential in modern synthetic chemistry

• Anthony J. Fernandes,
• Armen Panossian,
• Bastien Michelet,
• Agnès Martin-Mingot,
• Frédéric R. Leroux and
• Sébastien Thibaudeau

Beilstein J. Org. Chem. 2021, 17, 343–378, doi:10.3762/bjoc.17.32

• , Vasilyev and Khoroshilova investigated the superacid-promoted activation of α-(trifluoromethyl) silyl ethers exhibiting a thiophene core [73]. At 0 °C, thiophenes 72-Cl and 72-Br undergo electrophilic dimerization, affording a mixture of 73-Cl and 73-Br (Scheme 20). When the reaction was cooled to −60 °C

An atom-economical addition of methyl azaarenes with aromatic aldehydes via benzylic C(sp³)–H bond functionalization under solvent- and catalyst-free conditions

• Divya Rohini Yennamaneni,
• Vasu Amrutham,
• Krishna Sai Gajula,
• Rammurthy Banothu,
• Murali Boosa and
• Narender Nama

Beilstein J. Org. Chem. 2020, 16, 3093–3103, doi:10.3762/bjoc.16.259

• heteroaromatic aldehyde 2-pyridinecarbaldehyde (2q) gave the respective dehydrated product 4q in 96% yield, whereas 2-thiophene (2r) resulted in the desired product 3r but in a low yield (Table 2, entries 17 and 18). Subsequently, several azaarenes in combination with 4-nitrobenzaldehyde (2a) were also evaluated

Deoxyfluorination of acyl fluorides to trifluoromethyl compounds by FLUOLEAD^®/Olah’s reagent under solvent-free conditions

• Yumeng Liang,
• Akihito Taya,
• Zhengyu Zhao,
• Norimichi Saito and
• Norio Shibata

Beilstein J. Org. Chem. 2020, 16, 3052–3058, doi:10.3762/bjoc.16.254

• fluoride (1i) also furnished trifluoromethylbenzene (2i) in an excellent yield (99%). Substrates with two substituents, such as 3,5-dibutyl, 1-bromo-2-methyl, and 1,2-diethoxy groups (1j–l), furnished the desired products 2j–l in good to excellent yields (66–99%). The heteroaryl group of 2-thiophene (1m

Synthesis and characterization of S,N-heterotetracenes

• Astrid Vogt,
• Florian Henne,
• Christoph Wetzel,
• Elena Mena-Osteritz and
• Peter Bäuerle

Beilstein J. Org. Chem. 2020, 16, 2636–2644, doi:10.3762/bjoc.16.214

• . 250, 64293 Darmstadt, Germany 10.3762/bjoc.16.214 Abstract The synthesis and optoelectronic properties of novel S,N-heterotetracenes consisting of fused heterocyclic thiophene and pyrrole rings are presented. Tetracyclic and benzannulated derivatives with a varying number and sequence of sulfur and

• replacement of sulfur by nitrogen atoms in the tetra- and hexacyclic systems leads to a red-shift in absorption, a decrease in oxidation potential and energy gap. On the other hand, the replacement of a thiophene ring by benzene leads to the opposite effects. Keywords: Buchwald–Hartwig amination; Cadogan

• ]. The series of thienoacenes consisting of only fused thiophene rings has been synthesized up to an octamer, whereby the longer members in the series quickly lose solubility [4][5][6]. The implementation of pyrrole rings into the fused ladder-type structure leads to the class of S,N-heteroacenes

Synthetic approaches to bowl-shaped π-conjugated sumanene and its congeners

• Shakeel Alvi and
• Rashid Ali

Beilstein J. Org. Chem. 2020, 16, 2212–2259, doi:10.3762/bjoc.16.186

• treating the commercially available triphenylene derivative 152 with n-BuLi in the presence of tetramethylethylenediamine (TMEDA) to produce the hexalithiated intermediate which on further treatment with sulfur powder generated the compound 153 having 1,2-dithiin rings as well as one thiophene ring. Later

Natural dolomitic limestone-catalyzed synthesis of benzimidazoles, dihydropyrimidinones, and highly substituted pyridines under ultrasound irradiation

• Kumar Godugu,
• Venkata Divya Sri Yadala,
• Mohammad Khaja Mohinuddin Pinjari,
• Trivikram Reddy Gundala,
• Lakshmi Reddy Sanapareddy and
• Chinna Gangi Reddy Nallagondu

Beilstein J. Org. Chem. 2020, 16, 1881–1900, doi:10.3762/bjoc.16.156

• ) in different positions provided good to excellent isolated yields of the corresponding products 3b–g and 3j–o that ranged from 94 to 98% in a stipulated period of time, as specified in Table 5. Further, heteroaromatic aldehydes, such as furan-2-aldehyde (2p) and thiophene-2-aldehyde (2q) produced the

• 3-Br: 2s) underwent the reaction with ethyl acetoacetate (4) and urea (5) to form the corresponding products (7h–j) in good isolated yields that ranged from 93–96% (Table 6, entries 8–10). Heteroaromatic aldehydes, such as furan-2-aldehyde (2p) and thiophene-2-aldehyde (2q) showed a good reactivity

Synthesis and highly efficient light-induced rearrangements of diphenylmethylene(2-benzo[b]thienyl)fulgides and fulgimides

• Vladimir P. Rybalkin,
• Sofiya Yu. Zmeeva,
• Lidiya L. Popova,
• Valerii V. Tkachev,
• Andrey N. Utenyshev,
• Olga Yu. Karlutova,
• Alexander D. Dubonosov,
• Vladimir A. Bren,
• Sergey M. Aldoshin and
• Vladimir I. Minkin

Beilstein J. Org. Chem. 2020, 16, 1820–1829, doi:10.3762/bjoc.16.149

• -isomers and of products of the photoinduced rearrangement completed by 1,5-H shift reaction, 3a,4-dihydronaphtho[2,3-c]furans(pyrroles) C, were established based on the data of 1H and 13C NMR spectroscopy and X-ray diffraction studies. Keywords: benzo[b]thiophene; fulgide; fulgimide; photorearrangement

• investigation of their photoinduced rearrangements. Results and Discussion Fulgides 3E, 3Z, 7E and fulgimides 4E, 4Z, 8E were synthesized as shown in Scheme 2 and Scheme 3. The Stobbe condensation of dimethyl 2-(diphenylmethylene)succinate with 1-methoxy- and 1-chlorobenzo[b]thiophene-2-carbaldehydes was used

• fulgides 3Z and 3E are shown in Figure 1 and Figure 2. Fulgide 3Z possesses Z-configuration at the double bond С(4)=С(5). The 3-methoxy-2-benzo[b]thiophene moiety in 3Z is planar and is almost coplanar with the planar furan-2,5-dione fragment (the dihedral angle is equal to 3.9°). The phenyl rings are

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

• . The quantum yields were calculated based on Equation 1. where R means reference and S sample, respectively. Generally weak fluorescence emissions were observed for the thiophene-based chromophores due to a remarkable spin–orbit coupling which is originating from the heavy atom effect of sulfur [73][74

• gel (CHCl3/MeOH 95:5, v/v) to afford the analytically pure product 2bA as orange solid in 74% yield (two step yield). One-pot experimental procedure for the synthesis of methyl 1-(benzo[b]thiophene-2-carbonyl)-9H-pyrido[3,4-b]indole-3-carboxylate (6C). To a stirred suspension of Cs2CO3 (0.182 g, 0.560

Azidophosphonium salt-directed chemoselective synthesis of (E)/(Z)-cinnamyl-1H-triazoles and regiospecific access to bromomethylcoumarins from Morita–Baylis–Hillman adducts

• Soundararajan Karthikeyan,
• Radha Krishnan Shobana,
• Kamarajapurathu Raju Subimol,
• J. Helen Ratna Monica and
• Ayyanoth Karthik Krishna Kumar

Beilstein J. Org. Chem. 2020, 16, 1579–1587, doi:10.3762/bjoc.16.130

• reactions. We further extended the scope of this transformation to five-membered heterocyclic MBH adducts. To our delight, except pyrroles, the proposed methodology was amenable to MBH adducts of furan and thiophene (3n–q, 70–80%). The mechanistic pathway for the triazolation proceeded via a nucleophilic

NHC-catalyzed enantioselective synthesis of β-trifluoromethyl-β-hydroxyamides

• Alyn T. Davies,
• Mark D. Greenhalgh,
• Alexandra M. Z. Slawin and
• Andrew D. Smith

Beilstein J. Org. Chem. 2020, 16, 1572–1578, doi:10.3762/bjoc.16.129

• expected lower electrophilicity. A heterocyclic substituent could also be incorporated using this methodology, with thiophene-substituted β-trifluoromethyl-β-hydroxyamide 16 being produced in 80:20 dr, with purification giving 16 in 51% yield as a single diastereoisomer and 96:4 er. The substrate scope was

Photoredox-catalyzed silyldifluoromethylation of silyl enol ethers

• Vyacheslav I. Supranovich,
• Vitalij V. Levin and
• Alexander D. Dilman

Beilstein J. Org. Chem. 2020, 16, 1550–1553, doi:10.3762/bjoc.16.126

• -donating functional groups. Substrates containing pyridine, furan, and thiophene as heterocyclic fragments were also successfully converted into the corresponding alcohols 4. However, in the reaction of the enol ether derived from 2-acetyl-N-methylpyrrole, ketone 3p did not undergo reduction with sodium

Heterogeneous photocatalysis in flow chemical reactors

• Christopher G. Thomson,
• Ai-Lan Lee and
• Filipe Vilela

Beilstein J. Org. Chem. 2020, 16, 1495–1549, doi:10.3762/bjoc.16.125

Photocatalytic trifluoromethoxylation of arenes and heteroarenes in continuous-flow

• Alexander V. Nyuchev,
• Ting Wan,
• Borja Cendón,
• Carlo Sambiagio,
• Job J. C. Struijs,
• Michelle Ho,
• Moisés Gulías,
• Ying Wang and
• Timothy Noël

Beilstein J. Org. Chem. 2020, 16, 1305–1312, doi:10.3762/bjoc.16.111

• poor yields. Other synthetically useful substituents, including cyano, nitro, phenylsulphonyl, (pinacolato)boron, and alkyl groups could be tolerated in the reaction (24–30), leading to a yield range between 26 and 65%. The trifluoromethoxylation of pyridine, pyrimidine, and thiophene derivatives also

Photocatalysis with organic dyes: facile access to reactive intermediates for synthesis

• Stephanie G. E. Amos,
• Marion Garreau,
• Luca Buzzetti and
• Jerome Waser

Beilstein J. Org. Chem. 2020, 16, 1163–1187, doi:10.3762/bjoc.16.103

• the substrate 15.1 using dibenzothiophene S-oxide (DBTSO, 15.2). Then, under visible-light irradiation, 15.3 could be reduced with PHTH (OD16) to generate an aryl radical that could further be trapped by a heteroarene 15.4, such as pyrrole or thiophene, furnishing the arylation product 15.5. Acyl

A simple and easy to perform synthetic route to functionalized thienyl bicyclo[3.2.1]octadienes

• Dragana Vuk,
• Irena Škorić,
• Valentina Milašinović,
• Krešimir Molčanov and
• Željko Marinić

Beilstein J. Org. Chem. 2020, 16, 1092–1099, doi:10.3762/bjoc.16.96

• 54, 10000 Zagreb, Croatia NMR Centre, Ruđer Bošković Institute, Bijenička cesta 54, 10000 Zagreb, Croatia 10.3762/bjoc.16.96 Abstract In order to prepare novel polycyclic derivatives of bicyclo[3.2.1]octadiene systems fused with a thiophene ring, photochemical cyclization and aldol condensation

• reactions were carried out. The starting substrates were easily obtained by a Vilsmeier–Haack reaction of bicyclo[3.2.1]octadiene thiophene derivatives with dimethylformamide. From the obtained carbaldehydes, novel methyl, methoxy, and cyano-substituted styryl thienobenzobicyclo[3.2.1]octadiene derivatives

• [3.2.1]octadiene compound with an extended conjugation. Keywords: bicyclo[3.2.1]octadiene; photocyclization; thiophene; Vilsmeier–Haack reaction; Wittig reaction; Introduction The bicyclo[3.2.1]octane skeleton has become the subject of intensive research in recent years [1][2][3]. Its presence in

Copper-based fluorinated reagents for the synthesis of CF₂R-containing molecules (R ≠ F)

• Louise Ruyet and
• Tatiana Besset

Beilstein J. Org. Chem. 2020, 16, 1051–1065, doi:10.3762/bjoc.16.92

• oxazoles (17 examples, up to 87% yield) were difluoromethylated but a variety of other heteroarenes turned out to be suitable such as pyridine, imidazole, benzo[d]thiazole, benzo[b]thiophene, benzo[d]oxazole, thiazole and thiophene derivatives (Scheme 6). Copper-based CF2FG-containing reagents Besides the

Synthesis and properties of tetrathiafulvalenes bearing 6-aryl-1,4-dithiafulvenes

• Aya Yoshimura,
• Hitoshi Kimura,
• Kohei Kagawa,
• Mayuka Yoshioka,
• Toshiki Itou,
• Dhananjayan Vasu,
• Takashi Shirahata,
• Hideki Yorimitsu and
• Yohji Misaki

Beilstein J. Org. Chem. 2020, 16, 974–981, doi:10.3762/bjoc.16.86

• ][15][16]. Considerable efforts have been devoted to the development of peripherally benzene- or thiophene-substituted TTFs. As for peripherally benzene-functionalized TTFs, some synthetic approaches, crystal and electronic structures, electrochemical and optical properties, and the nature of radical

• ion complexes with DDQ or iodine were reported [17][18][19][20][21][22][23][24]. Peripherally thiophene-functionalized TTFs, as potential precursors to conducting polymers, and organic metals were also prepared and characterized [25][26][27][28][29]. To design more tempting molecules, the attachment

Recent applications of porphyrins as photocatalysts in organic synthesis: batch and continuous flow approaches

• Rodrigo Costa e Silva,
• Luely Oliveira da Silva,
• Aloisio de Andrade Bartolomeu,
• Timothy John Brocksom and
• Kleber Thiago de Oliveira

Beilstein J. Org. Chem. 2020, 16, 917–955, doi:10.3762/bjoc.16.83

• reported a metal-free photoarylation of five-membered heteroarenes with aryldiazonium salts and meso-arylated porphyrin derivatives as photoredox catalyst [11]. Compounds such as furan, thiophene, and N-Boc-pyrrole derivatives were obtained by this methodology in 29–81% yields (Scheme 3). The key-step of

• energies, as for example the thiaporphyrins that absorb beyond 650 nm [8][28]. Derksen and co-workers studied bond-cleavage reactions that can occur in biological microenvironments, using a light source with wavelengths frequently employed in photomedicine (650–850 nm) and thiophene-containing porphyrins