Synthesis of phenanthridines via a novel photochemically-mediated cyclization and application to the synthesis of triphaeridine

• Songeziwe Ntsimango,
• Kennedy J. Ngwira,
• Moira L. Bode and
• Charles B. de Koning

Beilstein J. Org. Chem. 2021, 17, 2340–2347, doi:10.3762/bjoc.17.152

• ], rhodium-mediated alkyne [2 + 2 + 2] cycloaddition reactions [3], and the palladium-catalysed aerobic domino Suzuki coupling/Michael addition reaction [4]. The most attractive and common strategies to phenanthridines rely on intramolecular cyclizations of various ortho-functionalized biaryl precursors

• . Experimental For general experimental procedures, please consult Supporting Information File 1. Suzuki coupling: general procedure To a deoxygenated 0.25 M solution of arylboronic acid (1.2 equiv) in DME stirring under argon was added aryl bromide (1.0 equiv), Pd(PPh3)4 (10 mol %) and deoxygenated 2 M aqueous

Chemical syntheses and salient features of azulene-containing homo- and copolymers

• Vijayendra S. Shetti

Beilstein J. Org. Chem. 2021, 17, 2164–2185, doi:10.3762/bjoc.17.139

• -dibromo-[2-(3-dodecylthien-2-yl)]azulene (46) by using two successive Suzuki coupling reactions with thiophene boron ester 47 and biphenyl-4,4’-diboronic acid bis(pinacol) ester 49 (Scheme 11), whereas the Suzuki coupling of 46 with 2,1,3-benzothiadiazole-4,7-bis(boronic acid pinacol ester) 51 yielded the

• discouraged the protonation. In 2013, Xu and co-workers [42] reported the synthesis of azulene-fluorene-benzothiadiazole terpolymers 136–138, containing varying degrees of azulene and benzothiadiazole units in good yields by adopting the Suzuki coupling protocol (Scheme 23). The polymers 136–138 were of

Recent advances in the syntheses of anthracene derivatives

• Giovanni S. Baviera and
• Paulo M. Donate

Beilstein J. Org. Chem. 2021, 17, 2028–2050, doi:10.3762/bjoc.17.131

• 129a and 129b in two steps. First, they subjected dibromides 127 to a double Suzuki coupling with 4-alkylphenylboronic acids, to obtain the terphenyl derivatives 128. Then, the authors converted compounds 128, in moderate yield (54–55%), to the corresponding 6,8-diiododibenzo[a,j]anthracenes 129a and

• ]anthracenes 139 bearing H, CN, or OMe groups at positions 11 and 12, to study their liquid crystalline properties (Scheme 32) [66]. Their methodology started with a Suzuki coupling reaction of substituted dibromonaphthalenes 136 and boronate diesters 137, to provide the corresponding 2,3-diphenylnaphthalenes

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

• components of the OSC. The synthesis of such compounds is also based on the Suzuki coupling reaction between alkylated 6,6’-dibromoisoindigos and corresponding arylboronic derivatives, leading to the formation of target molecules in moderate yield (Scheme 11). In these compounds, the triarylamine substituent

Double-headed nucleosides: Synthesis and applications

• Vineet Verma,
• Jyotirmoy Maity,
• Vipin K. Maikhuri,
• Ritika Sharma,
• Himal K. Ganguly and
• Ashok K. Prasad

Beilstein J. Org. Chem. 2021, 17, 1392–1439, doi:10.3762/bjoc.17.98

• -workers [74][75]. The boronic esters (136a,b) were coupled with 5′-O-DMTr-2′-deoxy-5-iodouridine (135) via Suzuki coupling to give double-headed nucleosides 137 and 138 (Scheme 34) [73]. The double-headed nucleosides 5′-O-dimethoxytrityl-5-(3-(thymin-1-yl)phenyl)ethynyl-2′-deoxyuridine (140) and 5′-O

Synthetic accesses to biguanide compounds

• Oleksandr Grytsai,
• Cyril Ronco and
• Rachid Benhida

Beilstein J. Org. Chem. 2021, 17, 1001–1040, doi:10.3762/bjoc.17.82

• catalysts in various organic reactions [1] such as the Ullmann coupling, Suzuki coupling, Suzuki–Miyaura coupling, and the Heck reaction. Aside from being useful synthetic agents, biguanides gained particular interest from the perspective of medicinal chemistry. For the first time, the biological activity

Total synthesis of decarboxyaltenusin

• Lucas Warmuth,
• Aaron Weiß,
• Marco Reinhardt,
• Anna Meschkov,
• Ute Schepers and
• Joachim Podlech

Beilstein J. Org. Chem. 2021, 17, 224–228, doi:10.3762/bjoc.17.22

• -3,5-dimethoxybenzene, where the longest linear sequence consists of five steps. The key reaction was a palladium-catalyzed Suzuki coupling of an aromatic boronate with a brominated resorcin derivative. Keywords: biaryls; boronates; mycotoxins; polyketides; Suzuki coupling; Introduction 5’-Methoxy-6

• analysis, we envisioned a Suzuki coupling of two suitably substituted arenes. Silyl protecting groups like the tert-butyldimethylsilyl group (TBS) were considered appropriate for all projected reaction steps. The boronate moiety 6a was prepared starting with 4-methylcatechol (2), which was initially

• a 73% yield. The Suzuki coupling of boronate 6a and aryl bromide 9a using palladium acetate and cesium carbonate in the presence of the ligand SPhos [25] yielded biaryl 10a with virtually quantitative yield (98%, Scheme 4). Unfortunately, the removal of non-identified byproducts and of 9a (which had

Progress in the total synthesis of inthomycins

• Bidyut Kumar Senapati

Beilstein J. Org. Chem. 2021, 17, 58–82, doi:10.3762/bjoc.17.7

• access to dienylboronate (rac)-19a in 43% yield. A competitive Suzuki coupling was also observed with compound (rac)-19b being isolated in 35% yield [32][33][34][35]. Dienylboronate (rac)-19a was then transformed into dienyl iodide (rac)-20 by iodine monochloride addition and methoxide-mediated

• -catalyzed hydroboration of the terminal acetylene in 127 gave (E,E)-128 in good yield and with complete stereocontrol (Scheme 18). To accomplish the key Suzuki coupling of dienylboronic ester 128, the necessary alkenyl iodides (Z)- and (E)-130 were prepared from the propargyl alcohol (14) in good yields

•  19). For the synthesis of inthomycin B ((+)-2), a Suzuki coupling reaction between (E,E)-128 and (Z)-(+)-130a was performed in the presence of palladium(II) acetate, triphenylphosphine, and aqueous sodium carbonate to give (E,E,Z)-triene (+)-131 selectively in 64% yield. Treatment of triene (+)-131

Circularly polarized luminescent systems fabricated by Tröger's base derivatives through two different strategies

• Cheng Qian,
• Yuan Chen,
• Qian Zhao,
• Ming Cheng,
• Chen Lin,
• Juli Jiang and
• Leyong Wang

Beilstein J. Org. Chem. 2021, 17, 52–57, doi:10.3762/bjoc.17.6

• ]. Then, by Suzuki coupling reaction between 2,8-dibromo-6H,12H-5,11-methanodibenzo[b,f][1,5]diazocine and 4-vinylpyridine, rac-TBPP was successfully obtained in 51.8% yield. Detailed experiments and characterization were described in Supporting Information File 1 (Figures S1–S3). Firstly, rac-TBPP was

Synthesis, crystal structures and properties of carbazole-based [6]helicenes fused with an azine ring

• Daria I. Tonkoglazova,
• Anna V. Gulevskaya,
• Konstantin A. Chistyakov and
• Olga I. Askalepova

Beilstein J. Org. Chem. 2021, 17, 11–21, doi:10.3762/bjoc.17.2

• , iPr2NH, DMSO, 80 °C, 24 h, argon. Suzuki coupling of compounds 1a,b with 9-ethyl-3-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-9H-carbazole. Suzuki coupling of compounds 3 with 9-ethyl-3-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-9H-carbazole. ICl-induced cyclyzation of compounds 2 and 6

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

• monoiodosumanene 79, which was prepared via an alternate route using 6,6’-diiodo-2,2’-dimethoxy-1,1’-binaphthol in the presence of Sc(OTf)3. The Suzuki-coupling reaction between 1-pyreneboronic acid and iodosumanene 79 furnished the desired compound 93 in 84% yield (Scheme 22). Among the bowl-shaped π-conjugated

• reaction as the critical step [54]. Towards this goal, they started with the hexabromination of sumanene using bromine and iron powder in nitrobenzene to provide the desired compound 94 in 61% yield. Having the bromosumanene 94 in hand, it was then subjected to the Suzuki coupling with several arylboronic

• periphery. Thy employed the Suzuki coupling as the crucial step (Scheme 24) [55]. In contrast, very recently, Sakurai’s group has described the synthesis of 2,3,5,6,8,9-hexakis(phenoxycarbonyl)sumanene (97) from hexabromosumanene 94 as depicted in Scheme 24 [56]. Because of the low solubility of 94 in

Design and synthesis of diazine-based panobinostat analogues for HDAC8 inhibition

• Sivaraman Balasubramaniam,
• Sajith Vijayan,
• Liam V. Goldman,
• Xavier A. May,
• Kyra Dodson,
• Sweta Adhikari,
• Fatima Rivas,
• Davita L. Watkins and
• Shana V. Stoddard

Beilstein J. Org. Chem. 2020, 16, 628–637, doi:10.3762/bjoc.16.59

• performed a Suzuki coupling reaction between boronic acid 15 with chloro compound 2 (Scheme 2). To the best of our knowledge, there is no report of a Suzuki coupling reaction using boronic acid 15 in the literature. However, we generated this required boronic acid from the corresponding methyl propiolate

• the key intermediate aldehyde 25 (Scheme 4). Initially, we explored the Suzuki coupling reaction for substrate 4. Gratifyingly, the reaction product 24 was produced in 41% yield from our developed synthetic strategy. Then, compound 24 was subjected to an SeO2 oxidation reaction. The oxidation reaction

Synthesis and optoelectronic properties of benzoquinone-based donor–acceptor compounds

• Daniel R. Sutherland,
• Nidhi Sharma,
• Georgina M. Rosair,
• Ifor D. W. Samuel,
• Ai-Lan Lee and
• Eli Zysman-Colman

Beilstein J. Org. Chem. 2019, 15, 2914–2921, doi:10.3762/bjoc.15.285

• difunctionalization is dependent on the electronics of the substituent added to BQ) [14], 5 was instead furnished from the dibromo-functionalized BQ 1-Br2 using a double Suzuki coupling. As expected, much harsher conditions (100 °C) were required to achieve conversions under Pd(0) catalysis to produce 5 in 22% yield

• consistent with 3 having higher ΦPL than the other compounds. Conclusion Three novel monofunctionalized donor–acceptor BQ derivatives 2–4 were synthesized using an efficient Pd-catalyzed C–H functionalization method, and novel 2,5-difunctionalized BQ derivative 5 was also obtained via Suzuki coupling. The

• monofunctionalization of BQ (1). Synthesis of 5 via double Suzuki coupling. Electrochemical properties of 2–5. Optoelectronic properties of 2–5. Supporting Information The research data supporting this publication can be accessed at https://doi.org/10.17630/178f3a7c-4717-43f0-a145-049675825e1a. Supporting Information

Arylisoquinoline-derived organoboron dyes with a triaryl skeleton show dual fluorescence

• Vânia F. Pais,
• Tristan Neumann,
• Ignacio Vayá,
• M. Consuelo Jiménez,
• Abel Ros and
• Uwe Pischel

Beilstein J. Org. Chem. 2019, 15, 2612–2622, doi:10.3762/bjoc.15.254

• -coupling reactions was planned. Starting from 1-bromo-4-methoxynaphthalene (1), the Pd-catalyzed Suzuki coupling reaction with commercial boronic acids afforded the naphthyl and pyrenyl derived methyl ethers 2 and 3 in 78% and 87% yield, respectively (Scheme 1). For the synthesis of the anthryl derivative

• 5 a Pd-catalyzed one-pot reaction consisting of a borylation and Suzuki coupling was applied. Thus, starting from 1-chloroanthracene (4) and using SPhos/Pd2dba3 (8:1) as the catalyst, a full conversion to the Miyaura-type borylated intermediate was achieved (TLC analysis) after 5 hours at 110 ºC

• triaryl systems 12–15 following a similar Pd-catalyzed one-pot borylation-Suzuki coupling strategy as mentioned above, using 1-chloroisoquinoline as the coupling partner (Scheme 3). The desired compounds 12–15 were obtained in 44–70% yield. The 1H NMR spectra, recorded at 25 °C, showed the coexistence of

A new approach to silicon rhodamines by Suzuki–Miyaura coupling – scope and limitations

• Thines Kanagasundaram,
• Antje Timmermann,
• Carsten S. Kramer and
• Klaus Kopka

Beilstein J. Org. Chem. 2019, 15, 2569–2576, doi:10.3762/bjoc.15.250

• PdCl2(PPh3)2 catalyst. Remarkably, the yield could be clearly enhanced by catalysis with PdCl2(dppf) and the thienyl-substituted fluorophore 30c could subsequently be synthesized in 91% yield. Table 3 compares the reaction outcome of the silicon rhodamine synthesis via Suzuki coupling with other

Targeted photoswitchable imaging of intracellular glutathione by a photochromic glycosheet sensor

• Xianzhi Chai,
• Hai-Hao Han,
• Yi Zang,
• Jia Li,
• Xiao-Peng He,
• Junji Zhang and
• He Tian

Beilstein J. Org. Chem. 2019, 15, 2380–2389, doi:10.3762/bjoc.15.230

• synthesis of dithienylethene fluorescence reporter Glyco-DTE is shown in Scheme 2. The dithienylethene derivative 3 was prepared by Suzuki coupling of dithienylethene 1 with methyl 4-bromobenzoate followed by hydrolysis with lithium hydroxide. The naphthalimide fluorophore 6 was synthesized through bromide

Azologization and repurposing of a hetero-stilbene-based kinase inhibitor: towards the design of photoswitchable sirtuin inhibitors

• Christoph W. Grathwol,
• Nathalie Wössner,
• Sören Swyter,
• Adam C. Smith,
• Enrico Tapavicza,
• Robert K. Hofstetter,
• Anja Bodtke,
• Manfred Jung and
• Andreas Link

Beilstein J. Org. Chem. 2019, 15, 2170–2183, doi:10.3762/bjoc.15.214

• -bromonicotinate (3b). If 3b was used, transformation to the nicotinamide was accomplished almost quantitatively by addition of a saturated solution of ammonia in anhydrous methanol and stirring in a closed vessel at 40 °C. Compounds 4a and b could easily be obtained through Suzuki coupling with commercially

Recent advances on the transition-metal-catalyzed synthesis of imidazopyridines: an updated coverage

• Gagandeep Kour Reen,
• Ashok Kumar and
• Pratibha Sharma

Beilstein J. Org. Chem. 2019, 15, 1612–1704, doi:10.3762/bjoc.15.165

Remarkable effect of alkynyl substituents on the fluorescence properties of a BN-phenanthrene

• Alberto Abengózar,
• David Sucunza,
• Patricia García-García and
• Juan J. Vaquero

Beilstein J. Org. Chem. 2019, 15, 1257–1261, doi:10.3762/bjoc.15.122

• reactions of 1b, under conditions optimized for a related BN-benzo[c]phenanthrene [30]. Gratifyingly, Suzuki coupling and Buchwald–Hartwig amination yielded the corresponding aryl- and amino-substituted BN-phenanthrenes 1c and 1d in good yields (Scheme 2). Moreover, Sonogashira couplings efficiently proceed

Heck- and Suzuki-coupling approaches to novel hydroquinone inhibitors of calcium ATPase

• Robert J. Kempton,
• Taylor A. Kidd-Kautz,
• Soizic Laurenceau and
• Stefan Paula

Beilstein J. Org. Chem. 2019, 15, 971–975, doi:10.3762/bjoc.15.94

• Abstract In this study, we explored Heck- and Suzuki-coupling methodology to modify the template 2,5-di-tert-butylhydroquinone (BHQ, 2), an inhibitor of the enzyme sarco/endoplasmic reticulum calcium ATPase (SERCA). We found that by utilizing Suzuki coupling, we could successfully attach a six-carbon

• convey specificity for prostate cancer cells. Keywords: calcium ATPase inhibitors; Heck- and Suzuki-coupling reactions; hydroquinones; prostate cancer; tethered amino acid; Introduction Sarco/endoplasmic reticulum calcium ATPase (SERCA) is an integral protein that resides in the membrane of the

• fully characterized) appeared to be the saturated derivative of 6 (2H triplets at δ 2.61 and 2.92; J = 7.3 Hz in the 1H NMR spectrum; signal at 2245 cm−1 in the IR spectrum). We next turned our attention to Suzuki coupling [10]. The reaction of commercially available 5-hexenenitrile with 9-BBN-H

A novel and efficient synthesis of phenanthrene derivatives via palladium/norbornadiene-catalyzed domino one-pot reaction

• Yue Zhong,
• Wen-Yu Wu,
• Shao-Peng Yu,
• Tian-Yuan Fan,
• Hai-Tao Yu,
• Nian-Guang Li,
• Zhi-Hao Shi,
• Yu-Ping Tang and
• Jin-Ao Duan

Beilstein J. Org. Chem. 2019, 15, 291–298, doi:10.3762/bjoc.15.26

• to multisubstituted arenes. In the previous work, we innovatively developed a strategy for the remote C–H alkylation of arenes [18]. Recently, our group also achieved aromatic ketones [19] and 2-alkynyl aromatic ketones [20] successfully through ortho-acylation and ipso-Suzuki coupling or

Quinolines from the cyclocondensation of isatoic anhydride with ethyl acetoacetate: preparation of ethyl 4-hydroxy-2-methylquinoline-3-carboxylate and derivatives

• Nicholas G. Jentsch,
• Jared D. Hume,
• Emily B. Crull,
• Samer M. Beauti,
• Amy H. Pham,
• Julie A. Pigza,
• Jacques J. Kessl and
• Matthew G. Donahue

Beilstein J. Org. Chem. 2018, 14, 2529–2536, doi:10.3762/bjoc.14.229

• heterocycle at position 4 is installed by Suzuki coupling with iodide 3a that is synthesized in three steps from ethyl aryl oxalate 4a. The α-ketoester side chain at position 3 was installed by selective halogen-metal exchange of iodide 5a with isopropylmagnesium chloride lithium chloride complex followed by

Synergistic approach to polycycles through Suzuki–Miyaura cross coupling and metathesis as key steps

• Sambasivarao Kotha,
• Milind Meshram and
• Chandravathi Chakkapalli

Beilstein J. Org. Chem. 2018, 14, 2468–2481, doi:10.3762/bjoc.14.223

• , Suzuki coupling of 79 with diverse arylboronic acids (e.g., phenylboronic acid (36)) gave a highly substituted naphthoxepine derivative 80 (90%) (Scheme 12). Stilbene derivatives Hoveyda and co-workers [44] reported the synthesis of Z-(pinacolato)allylboron and Z-(pinacolato)alkenylboron derivatives via

[3 + 2]-Cycloaddition reaction of sydnones with alkynes

• Veronika Hladíková,
• Jiří Váňa and
• Jiří Hanusek

Beilstein J. Org. Chem. 2018, 14, 1317–1348, doi:10.3762/bjoc.14.113

• , alkyl or alkenyl group via Suzuki coupling reaction with boronic acids to give otherwise rarely available 1,4,5-trisubstituted pyrazoles [119]. The second limitation is that the CuSAC reaction proceeds only with terminal alkynes. The latter fact clearly indicates some kind of participation of the

Recent advances in synthetic approaches for medicinal chemistry of C-nucleosides

• Kartik Temburnikar and
• Katherine L. Seley-Radtke

Beilstein J. Org. Chem. 2018, 14, 772–785, doi:10.3762/bjoc.14.65

• for the stability of 37 and to facilitate functional group interconversions as shown in Figure 12A [53]. In order to obtain carbocyclic C-nucleosides that resemble canonical nucleosides, Maier and coworkers synthesized a stable enol triflate (46, Figure 13A), which then enables Suzuki coupling and a

• modular synthesis of carbocyclic C-nucleosides [53]. The boronic acids/boronates (inset, Figure 13) of several (hetero)aryls were conducive to Suzuki coupling with the best result obtained when the C2', C3' and C5'–OHs were protected with TIPS and pivaloyl groups, respectively [53]. The cross-coupling

• separable mixture of diastereomers (2:1). In addition, optically pure cyclopentanone (−)-45 was obtained by converting the cyclopentane 43 to camphanates (51, Figure 13B) followed by separation of the diastereomers [53]. Subsequent synthesis of the enol triflate (−)-46 (Figure 13B), Suzuki coupling and