Synthesis of novel alkynyl imidazopyridinyl selenides: copper-catalyzed tandem selenation of selenium with 2-arylimidazo[1,2-a]pyridines and terminal alkynes

• Mio Matsumura,
• Kaho Tsukada,
• Kiwa Sugimoto,
• Yuki Murata and
• Shuji Yasuike

Beilstein J. Org. Chem. 2022, 18, 863–871, doi:10.3762/bjoc.18.87

• [1,2-a]pyridin-3-yl) diselenides using a Cu-catalyzed C–H selenation at the 3-position of 2-arylimidazo[1,2-a]pyridines with Se powder [32]. Initially, the reaction of bis(2-phenylimidazo[1,2-a]pyridin-3-yl) diselenide (2a), generated from Se powder and 2-phenylimidazo[1,2-a]pyridine (1a), with

• -pot reaction, both selanyl groups from the diselenide transferred to the product 4aa. When no base was added or the amount of the base was reduced, the yield of 4aa decreased significantly (Table 1, entries 9 and 10). Moreover, increasing the amount of the alkyne 1a or Na2CO3 did not affect the

• progress of the reaction (Table 1, entries 5, 11, and 12). Consequently, the optimal result was obtained when diselenide 2a was treated with equal amounts of alkyne 1a and two equivalents of Na2CO3 under aerobic conditions at room temperature (Table 1, entry 5). The reaction was also attempted by mixing

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

• hydroquinone ethers [87]. The combination of tert-butyl hydroperoxide and poly(bis-1,2-phenyl)diselenide was the one that showed the best result: 90% yield after 12 h reaction and recrystallization (Table 3, entry 3). Construction of the naphthoquinone ring In addition to the oxidation of naphthalene

• respective ditellurides, a disulfide and a diselenide (Scheme 27). Recently, Ribeiro and co-workers used menadione as a nucleophile for the synthesis of 3-chloromethylated menadione 84, a key intermediate used to prepare selenium-menadione conjugates 86 [128]. In this work, compound 84 was prepared through

Iron-catalyzed domino coupling reactions of π-systems

• Austin Pounder and
• William Tam

Beilstein J. Org. Chem. 2021, 17, 2848–2893, doi:10.3762/bjoc.17.196

Recent advances in the tandem annulation of 1,3-enynes to functionalized pyridine and pyrrole derivatives

• Yi Liu,
• Puying Luo,
• Yang Fu,
• Tianxin Hao,
• Xuan Liu,
• Qiuping Ding and
• Yiyuan Peng

Beilstein J. Org. Chem. 2021, 17, 2462–2476, doi:10.3762/bjoc.17.163

• selenyl-substituted nicotinates 18 in excellent yield. Electron-donating and electron-withdrawing group-substituted diaryl diselenides, 1,2-di(thiophen-2-yl)diselane, and dimethyl diselenide were compatible to give the corresponding products 18. The sulfenylamination of (E)-2-en-4-ynyl azides 1 could also

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

• attacks the Cu(III) intermediate 87, formed via the reaction between diaryl diselenide 84 and the bimetallic complex [L2Cu]2I2. Next, the produced intermediate 88 undergoes a reductive elimination to achieve intermediate 89 with regeneration of the Cu complex [L2Cu]2I2. Then, nucleophilic attack of the

• aryl selenide anion to the antimony atom takes place to give 5-selanyltriazole 85 and Ph2Sb–SeAr. Ph2Sb–SeAr is hydrolyzed in aqueous medium to give selenol 90 and Ph2SbOH. Selenol 90 is oxidized in air and transformed into diselenide 84. Therefore, only 0.5 equiv of diaryl diselenide were necessary

Oxime radicals: generation, properties and application in organic synthesis

• Igor B. Krylov,
• Stanislav A. Paveliev,
• Alexander S. Budnikov and
• Alexander O. Terent’ev

Beilstein J. Org. Chem. 2020, 16, 1234–1276, doi:10.3762/bjoc.16.107

Synthesis and anticancer activity of bis(2-arylimidazo[1,2-a]pyridin-3-yl) selenides and diselenides: the copper-catalyzed tandem C–H selenation of 2-arylimidazo[1,2-a]pyridine with selenium

• Mio Matsumura,
• Tsutomu Takahashi,
• Hikari Yamauchi,
• Shunsuke Sakuma,
• Yukako Hayashi,
• Tadashi Hyodo,
• Tohru Obata,
• Kentaro Yamaguchi,
• Yasuyuki Fujiwara and
• Shuji Yasuike

Beilstein J. Org. Chem. 2020, 16, 1075–1083, doi:10.3762/bjoc.16.94

• ]pyridin-3-yl] diselenide showed an excellent anticancer activity and low cytotoxicity toward noncancer cells, suggesting that this diselenide is a potential lead compound for anticancer therapy. Keywords: anticancer activity; copper catalyst; diselenide; imidazopyridine; selenide; selenium; Introduction

• variety of methods [14][15], and many of the targets exhibited biological activity (Figure 1). For example, bis(2-pyridyl) diselenide I has the potential to mitigate oxidative stress and inhibits the AChE activity [16], bis(quinolin-8-yl) diselenide (II) exhibited antioxidant activity in a skin cell model

• selenium source in the presence of a transition metal catalyst, such as Cu or Ni [27][28][29][30][31][32]. In 2011, Zhou et al. reported the pioneering Cu-catalyzed C–H selenation of 2-arylimidazopyridine with diphenyl diselenide in the presence of CuI (10 mol %) [29]. Tandem reactions involving the

Regio- and stereoselective synthesis of new ensembles of diversely functionalized 1,3-thiaselenol-2-ylmethyl selenides by a double rearrangement reaction

• Svetlana V. Amosova,
• Andrey A. Filippov,
• Nataliya A. Makhaeva,
• Alexander I. Albanov and
• Vladimir A. Potapov

Beilstein J. Org. Chem. 2020, 16, 515–523, doi:10.3762/bjoc.16.47

• the generation of sodium 1,3-thiaselenol-2-ylmethylselenolate from 1,3-thiaselenol-2-ylmethyl selenocyanate or bis(1,3-thiaselenol-2-ylmethyl) diselenide followed by nucleophilic substitution reactions. Sodium 1,3-thiaselenol-2-ylmethylselenolate underwent nucleophilic addition to alkyl propiolates in

• % yields, respectively. The one-pot synthesis of hitherto unknown bis(1,3-thiaselenol-2-ylmethyl) diselenide (8) in 90% yield from thiaselenole 1 was developed (Scheme 10). The reaction proceeded via the formation of thiaselenole selenocyanate 4, which was in situ converted into diselenide 8. This compound

• consisted of two diastereomers, and two signals corresponding to each of them were observed in the 77Se NMR spectrum. Diselenide 8 was used as a starting material for the synthesis of 1,3-thiaselenol-2-ylmethylselanyl derivatives. Compounds 6a–j were prepared in 78–90% yields via the generation of sodium

Chiral terpene auxiliaries V: Synthesis of new chiral γ-hydroxyphosphine oxides derived from α-pinene

• Anna Kmieciak and
• Marek P. Krzemiński

Beilstein J. Org. Chem. 2019, 15, 2493–2499, doi:10.3762/bjoc.15.242

• -methyleneneoisopinocampheol (11) in 84% yield. In order to obtain two endocyclic allylic alcohols, (−)-β-pinene was chosen as the starting material for this synthesis (Scheme 3). Thus, β-pinene (12) was reacted with ozone to give (+)-nopinone (13) in 90% yield [27]. In the next step, 13 reacted with diphenyl diselenide and

Synthesis of benzo[d]imidazo[2,1-b]benzoselenoazoles: Cs₂CO₃-mediated cyclization of 1-(2-bromoaryl)benzimidazoles with selenium

• Mio Matsumura,
• Yuki Kitamura,
• Arisa Yamauchi,
• Yoshitaka Kanazawa,
• Yuki Murata,
• Tadashi Hyodo,
• Kentaro Yamaguchi and
• Shuji Yasuike

Beilstein J. Org. Chem. 2019, 15, 2029–2035, doi:10.3762/bjoc.15.199

• probably deprotonation of the heterocyclic rings with a base. Moreover, nucleophilic aromatic substitution (SNAr) reactions between an aryl halide and a selenium reagent such as aryl selenide anion or diaryl diselenide for C(Ar)–Se bond formation using a base have been reported [20][21][22]. However, the

• reaction mechanisms for these syntheses have not been reported. Therefore, we carried out several control experiments to clarify the reaction mechanism (Scheme 2). However, the reaction of 1-phenylbenzimidazole (11) without bromine at the phenyl group with diphenyl diselenide (12a) did not afford the

• corresponding 1-phenyl-2-(phenylselanyl)benzimidazole (13), and the reaction between 1-(2-bromophenyl)benzimidazole (1a) and di-p-tolyl diselenide (12b) gave 1-[2-(p-tolylselanyl)phenyl]benzimidazole (14) in only 30% yield. At present, the mechanism of this cyclization is unclear. We assume the reaction

Oxidative radical ring-opening/cyclization of cyclopropane derivatives

• Yu Liu,
• Qiao-Lin Wang,
• Zan Chen,
• Cong-Shan Zhou,
• Bi-Quan Xiong,
• Pan-Liang Zhang,
• Chang-An Yang and
• Quan Zhou

Beilstein J. Org. Chem. 2019, 15, 256–278, doi:10.3762/bjoc.15.23

• of the copper(II) acetate-mediated oxidative radical ring-opening/cyclization of MCPs with diphenyl diselenides is outlined in Scheme 5. Firstly, the phenylselenyl radical 14, generated from the homolytic cleavage of diphenyl diselenide, is added to the C–C double bond of MCPs to afford the

• radical intermediate 76. The intermediate 77, produced by the intramolecular cyclization of intermediate 76, reactes with diphenyl diselenide 73 to form the target product 74 via homolytic substitution (SH). In 2013, Ryu and co-workers developed the bromine radical-mediated ring-opening and alkylation of

Molecular iodine-catalyzed one-pot multicomponent synthesis of 5-amino-4-(arylselanyl)-1H-pyrazoles

• Camila S. Pires,
• Daniela H. de Oliveira,
• Maria R. B. Pontel,
• Jean C. Kazmierczak,
• Roberta Cargnelutti,
• Diego Alves,
• Raquel G. Jacob and
• Ricardo F. Schumacher

Beilstein J. Org. Chem. 2018, 14, 2789–2798, doi:10.3762/bjoc.14.256

• -(phenylselanyl)-1H-pyrazol-5-amine was submitted to an oxidative dehydrogenative coupling to produce a diazo compound confirmed by X-ray analysis. Keywords: diaryl diselenide; diazo compound; 1H-pyrazole; molecular iodine; multicomponent reaction; Introduction Selenium-containing compounds are of great

• (Scheme 2). The reaction is catalysed by molecular iodine in MeCN as solvent. Results and Discussion Initially, to optimize the reaction conditions experiments were performed using benzoylacetonitrile (1a), phenylhydrazine (2a) and diphenyl diselenide (3a) as standard substrates to define the best

• diphenyl diselenide (3a, 0.5 mmol) were solubilized in MeCN (3 mL) and molecular iodine (50 mol %) was added. The mixture was stirred at reflux temperature and after 48 h under these conditions, the expected product 4a was obtained in 71% yield (Table 1, entry 1). With these result, we attempted to

Glycosylation reactions mediated by hypervalent iodine: application to the synthesis of nucleosides and carbohydrates

• Yuichi Yoshimura,
• Hideaki Wakamatsu,
• Yoshihiro Natori,
• Yukako Saito and
• Noriaki Minakawa

Beilstein J. Org. Chem. 2018, 14, 1595–1618, doi:10.3762/bjoc.14.137

• diselenide 76 and deoxygenated 73 (Scheme 10). One of the reasons for the unsatisfactory result was the instability of selenoxide 74. Jeong et al. faced the same problem and suppressed decomposition by the immediate reaction after synthesizing the corresponding selenoxide [48]. To overcome these problems

CF₃SO₂X (X = Na, Cl) as reagents for trifluoromethylation, trifluoromethylsulfenyl-, -sulfinyl- and -sulfonylation. Part 1: Use of CF₃SO₂Na

• Hélène Guyon,
• Hélène Chachignon and
• Dominique Cahard

Beilstein J. Org. Chem. 2017, 13, 2764–2799, doi:10.3762/bjoc.13.272

Transition-metal-free one-pot synthesis of alkynyl selenides from terminal alkynes under aerobic and sustainable conditions

• Adrián A. Heredia and
• Alicia B. Peñéñory

Beilstein J. Org. Chem. 2017, 13, 910–918, doi:10.3762/bjoc.13.92

• the latter with K3PO4 generates the alkyl selenolate anion (RSe−) which reacts with another RSeCN molecule to give the corresponding diselenide R2Se2. Reduction of the latter diselenide by treatment with NaBH4 affords an alkyl selenolate anion, which reacts with styryl halide to give the desired

• reaction occurred with the formation of di-n-octyl selenide and di-n-octyl diselenide as byproducts, decreasing the yield of 5a to 56% and hampering its isolation. Similar results were obtained when adding n-octyl selenocyanate to a solution of alkynyl anion under N2 atmosphere followed by heating at 100

• environment and moderate acidity of the methylene protons in benzyl selenocyanate (7h) or dibenzyl diselenide (8h) may afford intermediates prone to decomposition, directly affecting formation of 5h. Furthermore, the electronic and steric effects offered by different substituents on the aryl moieties attached

Nucleophilic displacement reactions of 5′-derivatised nucleosides in a vibration ball mill

• Olga Eguaogie,
• Patrick F. Conlon,
• Francesco Ravalico,
• Jamie S. T. Sweet,
• Thomas B. Elder,
• Louis P. Conway,
• Marc E. Lennon,
• David R. W. Hodgson and
• Joseph S. Vyle

Beilstein J. Org. Chem. 2017, 13, 87–92, doi:10.3762/bjoc.13.11

• that of the putative corresponding diselenide (δSe 283.1). Belostotskii et al. have previously reported the synthesis of 5'-selenocyanate-nucleoside derivatives [35]; however, our approach offers the convenience of an 'off-the-shelf' reagent rather than requiring the synthesis of a tetrabutylammonium

O-Alkylated heavy atom carbohydrate probes for protein X-ray crystallography: Studies towards the synthesis of methyl 2-O-methyl-L-selenofucopyranoside

• Roman Sommer,
• Dirk Hauck,
• Annabelle Varrot,
• Anne Imberty,
• Markus Künzler and
• Alexander Titz

Beilstein J. Org. Chem. 2016, 12, 2828–2833, doi:10.3762/bjoc.12.282

• introduction of the methylseleno moiety was performed by nucleophilic substitution of the α-bromide in 5 with methylselenol obtained by in situ reduction of dimethyl diselenide with NaBH4 [23]. The obtained crude methyl β-selenofucoside was anomerized under Lewis acid catalysis to give the anomeric mixture in

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

• of oxidizing systems such as H2O2/aryl benzyl selenoxide and H2O2/diaryl diselenide is similar to that of m-chloroperbenzoic acid [212][232][233]. The main advantage of these selenium-containing systems is that the catalysts are regenerated and can therefore be used at low loadings [234][235][236

• diselenide system is presented in Table 3 [212]. In the first step of the catalytic cycle of the Baeyer–Villiger oxidation using diaryl diselenide 50 and hydrogen peroxide seleninic acid 51 is generated, which is then oxidized to perseleninic acid 52. Oxidation of the ketone 45 by perseleninic acid 52

• benzeneseleninoperoxoic anhydride [PhSe(O)O]2O in the first step, which then transforms to the active oxidant benzeneseleninoperoxoic acid PhSe(O)OOH [233]. The Baeyer–Villiger oxidation of (E)-α,β-unsaturated ketones to (E)-vinyl esters was performed with hydrogen peroxide and dibenzyl diselenide as pre-catalyst at room

Selected synthetic strategies to cyclophanes

• Sambasivarao Kotha,
• Mukesh E. Shirbhate and
• Gopalkrushna T. Waghule

Beilstein J. Org. Chem. 2015, 11, 1274–1331, doi:10.3762/bjoc.11.142

Electrochemical selenium- and iodonium-initiated cyclisation of hydroxy-functionalised 1,4-dienes

• Philipp Röse,
• Steffen Emge,
• Jun-ichi Yoshida and
• Gerhard Hilt

Beilstein J. Org. Chem. 2015, 11, 174–183, doi:10.3762/bjoc.11.18

• -dienols were transformed into cyclic phenylselenoethers by intramolecular cyclisation using selenium cations generated by indirect electrolysis. The reaction was carried out by electrolysing a mixture of the 1,4-dienol, diphenyl diselenide and tetraethylammonium bromide in CH3CN at room temperature in an

• undivided cell, using platinum foil electrodes (constant current 10 mA). In this investigation only diphenyl diselenide was used as selenium source. These reaction conditions led to the formation of products of type 3 as exclusive diastereomers (Scheme 2). The cyclisation of 2 could lead to a number of

• desired 1,4-diene. General procedure for the electrochemical seleno-alkoxylation of 1,4-dienols An undivided electrolysis cell was charged with diphenyl diselenide (78 mg, 0.25 mmol, 0.5 equiv), tetraethylammonium bromide (11 mg, 0.05 mmol, 0.1 equiv), the 1,4-diene (0.5 mmol, 1.0 equiv) and 10 mL

Selenium halide-induced bridge formation in [2.2]paracyclophanes

• Laura G. Sarbu,
• Henning Hopf,
• Peter G. Jones and
• Lucian M. Birsa

Beilstein J. Org. Chem. 2014, 10, 2550–2555, doi:10.3762/bjoc.10.266

• . Surprisingly, the addition of 2 equiv of PhSeCl to bis(acetylene) 1 again provided a mixture of dienes 2 and 3 along with diphenyl diselenide, in a 70% total isolated yield (Scheme 2). The ratio of isomeric dienes 2 and 3 was again 1:1.5, as resulted from the SeCl2 addition to 4,13-bis(ethynyl)[2.2

• ]paracyclophane. Moreover, an important experimental observation was the fact that diphenyl diselenide was formed in an equimolar amount with the isomeric dienes. This indicates a common intermediate for the reaction products from which elimination of diphenyl diselenide provides dienes 2 and 3. Based on

• . The reaction of 10 with the second equivalent of PhSeCl leads to selenonium ion 11; once the diphenyl diselenide leaving group is formed, the addition of chloride counter-anions from both directions is accompanied by the formation of [2.3.2](1,2,4)cyclophane derivatives 2 and 3. Most probably compound

Magnesium bis(monoperoxyphthalate) hexahydrate as mild and efficient oxidant for the synthesis of selenones

• Andrea Temperini,
• Massimo Curini,
• Ornelio Rosati and
• Lucio Minuti

Beilstein J. Org. Chem. 2014, 10, 1267–1271, doi:10.3762/bjoc.10.127

• handling and easier to use. Furthermore, the water soluble reaction byproducts magnesium phthalate and benzeneseleninate anion are generally easy to separate during work-up; the former could be recovered without additional purification as phthalic acid up to 85%, and the latter as diphenyl diselenide [21

Photoinduced synthesis of unsymmetrical diaryl selenides from triarylbismuthines and diaryl diselenides

• Yohsuke Kobiki,
• Shin-ichi Kawaguchi,
• Takashi Ohe and
• Akiya Ogawa

Beilstein J. Org. Chem. 2013, 9, 1141–1147, doi:10.3762/bjoc.9.127

• ). In 1999, Barton and co-workers reported that diaryl selenide was obtained by the reaction of triarylbismuthine with diphenyl diselenide under heating at high temperature (140 °C) [65], but the photoinduced reaction was not investigated. In this letter, we will report the radical reaction of diaryl

• diselenides with triarylbismuthines from the viewpoint of a photoinduced reaction in the synthesis of unsymmetrical diaryl selenides. Results and Discussion First, we investigated the photoinduced reaction of diphenyl diselenide with triphenylbismuthine. Diphenyl diselenide (1a, 0.1 mmol) and

• ( = 9 mm) contributed to the increase in the yield of 3aa (Table 1, entries 8 and 9). Next, we investigated the scope of the synthesis of unsymmetrical diaryl selenides by using different diaryl diselenides and triarylbismuthines (Table 2). The employed diaryl diselenides were diphenyl diselenide (1a

Isotopically labeled sulfur compounds and synthetic selenium and tellurium analogues to study sulfur metabolism in marine bacteria

• Nelson L. Brock,
• Christian A. Citron,
• Claudia Zell,
• Martine Berger,
• Irene Wagner-Döbler,
• Jörn Petersen,
• Thorsten Brinkhoff,
• Meinhard Simon and
• Jeroen S. Dickschat

Beilstein J. Org. Chem. 2013, 9, 942–950, doi:10.3762/bjoc.9.108

• including dimethyl diselenide (20) and dimethyl triselenide (21). In addition, the mixed sulfur/selenium compounds dimethylselenyl sulfide (15), bis(methylthio) selenide (16), methylseleno disulfide (17), methyl methylthio diselenide (18), and bis(methylseleno) sulfide (19) were found. A similar headspace

Substituent effect on the energy barrier for σ-bond formation from π-single-bonded species, singlet 2,2-dialkoxycyclopentane-1,3-diyls

• Jianhuai Ye,
• Yoshihisa Fujiwara and
• Manabu Abe

Beilstein J. Org. Chem. 2013, 9, 925–933, doi:10.3762/bjoc.9.106

• (s, COCH3), 185.47 (s, OC=O); ESIMS (m/z): [M + Na]+ calcd for C19H20O6Na, 367.11521; found, 367.11456. 1,3-Bis(3,5-dimethoxyphenyl)-2,2-dimethoxypropane-1,3-dione (5). 1,3-Dione 4 (2.76 g, 8 mmol) and diphenyl diselenide (1.25 g, 4 mmol) were dissolved in methanol (50 mL), and ammonium persulfate