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

• , substituted pyridine boronic acids [52][53][54] were coupled with intermediate 26 using Method III in DME–water to provide the desired 6-aryl products 37–40 (entries 12–15, Table 1). These results indicated that the DME–water solvent system was more favourable for more challenging Suzuki C–C coupling

Pyridine-promoted dediazoniation of aryldiazonium tetrafluoroborates: Application to the synthesis of SF₅-substituted phenylboronic esters and iodobenzenes

• George Iakobson,
• Junyi Du,
• Alexandra M. Z. Slawin and
• Petr Beier

Beilstein J. Org. Chem. 2015, 11, 1494–1502, doi:10.3762/bjoc.11.162

• literature describes the synthesis of 3- or 4-(pentafluorosulfanyl)phenylboronates or boronic acids from SF5-bromobenzenes via lithiation or magnesiation. These approaches suffer from low yields and other drawbacks [70][71]. For lithiation of the aryl bromide, t-BuLi had to be used and the formation of

Synthesis and properties of novel star-shaped oligofluorene conjugated systems with BODIPY cores

• Clara Orofino-Pena,
• Diego Cortizo-Lacalle,
• Joseph Cameron,
• Muhammad T. Sajjad,
• Pavlos P. Manousiadis,
• Neil J. Findlay,
• Alexander L. Kanibolotsky,
• Dimali Amarasinghe,
• Peter J. Skabara,
• Tell Tuttle,
• Graham A. Turnbull and
• Ifor D. W. Samuel

Beilstein J. Org. Chem. 2014, 10, 2704–2714, doi:10.3762/bjoc.10.285

• oligofluorenylboronic acids FnB (n = 1–4), synthesised by a known procedure [19], was used as the precursors for the nucleophilic coupling reagent. In the case of the T-Bn series, the convergent strategy was used for the synthesis of T-B1–T-B3 compounds using Suzuki coupling of the aforementioned oligofluorenyl boronic

• acids FnB (n = 1–3) with the core precursor compound T-B0Br [33], using conditions which proved to be efficient for coupling of BODIPY derivatives [30] (Scheme 2). The yields observed were 29–58%. Conversely, the T-B4 member of the series was synthesised by a semi-convergent approach, firstly via Suzuki

Exploration of C–H and N–H-bond functionalization towards 1-(1,2-diarylindol-3-yl)tetrahydroisoquinolines

• Michael Ghobrial,
• Marko D. Mihovilovic and
• Michael Schnürch

Beilstein J. Org. Chem. 2014, 10, 2186–2199, doi:10.3762/bjoc.10.226

• temperature under acidic conditions, employing boronic acids as aryl source [59]. Using this method the desired product 6a could be obtained but only in a low yield of 36% (Table 2, entry 1). Besides 6a also 12% of biphenyl could be isolated. Increasing the temperature to 50 °C proved to be counterproductive

• transformation. Obviously the steric bulk of the THIQ substituent in 3-position makes this transformation quite difficult. Hence it was decided to stick with the so far best conditions to investigate the scope of C2-arylation, the first step of route B (Scheme 2). Using substituted boronic acids led to decreased

Synthesis of rigid p-terphenyl-linked carbohydrate mimetics

• Maja Kandziora and
• Hans-Ulrich Reissig

Beilstein J. Org. Chem. 2014, 10, 1749–1758, doi:10.3762/bjoc.10.182

• successfully prepared [19]. The Suzuki cross-coupling is particularly suitable for carbohydrate chemistry due to the mild reaction conditions and its tolerance to a variety of functional groups [20]. In addition, the reactions are easy to perform and the required boronic acids exhibit exceptional stabilities

A convenient enantioselective decarboxylative aldol reaction to access chiral α-hydroxy esters using β-keto acids

• Zhiqiang Duan,
• Jianlin Han,
• Ping Qian,
• Zirui Zhang,
• Yi Wang and
• Yi Pan

Beilstein J. Org. Chem. 2014, 10, 969–974, doi:10.3762/bjoc.10.95

• stereocontrolled nucleophilic alkylation [15][16][17][18][19], alkynylation [20][21], 1,2-addition [22][23][24][25][26] and aldol reaction [27][28][29][30][31][32] have been developed. Various nucleophiles such as organometallics, boronic acids and unsaturated ketones can be tolerated in this context (Figure 2

Site-selective covalent functionalization at interior carbon atoms and on the rim of circumtrindene, a C₃₆H₁₂ open geodesic polyarene

• Hee Yeon Cho,
• Ronald B. M. Ansems and
• Lawrence T. Scott

Beilstein J. Org. Chem. 2014, 10, 956–968, doi:10.3762/bjoc.10.94

• available boronic acids. The reaction proceeds smoothly with 2-bromophenylboronic acid in the presence of Pd(0) and a base to furnish 29 (Scheme 9). The Suzuki reaction proceeds reasonably well, despite the potential complication of the product undergoing a subsequent Suzuki coupling with the bromine of the

Clean and fast cross-coupling of aryl halides in one-pot

• Valerica Pandarus,
• Geneviève Gingras,
• François Béland,
• Rosaria Ciriminna and
• Mario Pagliaro

Beilstein J. Org. Chem. 2014, 10, 897–901, doi:10.3762/bjoc.10.87

• involves a boron-containing nucleophile (a variety of aryl and heteroaryl boronic acids, esters, Ar-BBN, trifluoroborate and other boron species) and vinyl- or aryl halides as the electrophilic species. The use of the Suzuki–Miyaura reaction became routine both in industry and in research laboratories

• 80 °C in dioxane or in DMSO. In contrast to a number of Pd catalysts that are air sensitive, PdCl2(dppf) is air stable. This made the method more versatile and provided a long awaited easy way to synthesize a broad range of boronic esters that are conveniently used in place of boronic acids in the

Silver and gold-catalyzed multicomponent reactions

• Giorgio Abbiati and
• Elisabetta Rossi

Beilstein J. Org. Chem. 2014, 10, 481–513, doi:10.3762/bjoc.10.46

Boron-substituted 1,3-dienes and heterodienes as key elements in multicomponent processes

• Ludovic Eberlin,
• Fabien Tripoteau,
• François Carreaux,
• Andrew Whiting and
• Bertrand Carboni

Beilstein J. Org. Chem. 2014, 10, 237–250, doi:10.3762/bjoc.10.19

• and (E)-styrylboronic acid [12]. This was the first report of this type of transformation, which is now referred as the Petasis borono–Mannich reaction, and was later extended to a wide variety of other aldehydes, such as glyoxylic acid (for example), boronic acids, esters or trifluoroborates and

Recent advances in transition metal-catalyzed Csp²-monofluoro-, difluoro-, perfluoromethylation and trifluoromethylthiolation

• Grégory Landelle,
• Armen Panossian,
• Sergiy Pazenok,
• Jean-Pierre Vors and
• Frédéric R. Leroux

Beilstein J. Org. Chem. 2013, 9, 2476–2536, doi:10.3762/bjoc.9.287

• . investigated the copper-catalyzed trifluoromethylation of aryl and vinyl boronic acids with in situ generated CF3-radicals using NaSO2CF3 (Table 27 and Table 28) [97]. The CF3 radical is generated from the reaction of TBHP (t-BuOOH) with NaSO2CF3. Transmetallation of the arylboronic acid with the Cu(II

Consecutive cross-coupling reactions of 2,2-difluoro-1-iodoethenyl tosylate with boronic acids: efficient synthesis of 1,1-diaryl-2,2-difluoroethenes

• Ju Hee Kim,
• Su Jeong Choi and
• In Howa Jeong

Beilstein J. Org. Chem. 2013, 9, 2470–2475, doi:10.3762/bjoc.9.286

• Ju Hee Kim Su Jeong Choi In Howa Jeong Department of Chemistry & Medical Chemistry, Yonsei University, 1 Yonseidae-gil, Wonju, Gangwondo 220-710, Republic of Korea 10.3762/bjoc.9.286 Abstract The cross-coupling reactions of 2,2-difluoro-1-iodoethenyl tosylate (2) with 2 equiv of boronic acids in

• the presence of catalytic amounts of Pd(OAc)2 and Na2CO3 afforded the mono-coupled products 3 and 5 in high yields. The use of 4 equiv of boronic acids in the presence of catalytic amount of Pd(PPh3)2Cl2 and Na2CO3 in this reaction resulted in the formation of symmetrical di-coupled products 4 in high

• yields. Unsymmetrical di-coupled products 4 were obtained in high yields from the reactions of 3 with 2 equiv of boronic acids in the presence of catalytic amounts of Pd(OAc)2 and Na2CO3. Keywords: boronic acids; cross-coupling reaction; 1,1-diaryl-2,2-difluoroethene; 1,1-difluoro-1,3-dienes; 2,2

Synthesis, characterization and luminescence studies of gold(I)–NHC amide complexes

• Adrián Gómez-Suárez,
• David J. Nelson,
• David G. Thompson,
• David B. Cordes,
• Duncan Graham,
• Alexandra M. Z. Slawin and
• Steven P. Nolan

Beilstein J. Org. Chem. 2013, 9, 2216–2223, doi:10.3762/bjoc.9.260

• for the synthesis of such species using hydroxide 1: a) via transmetallation from either boronic acids or siloxides, or b) via deprotonation reactions of suitable substrates. We have applied the latter methodology to the synthesis of organogold–NHC complexes bearing several trans-ligands, such as

Palladium(II)-catalyzed Heck reaction of aryl halides and arylboronic acids with olefins under mild conditions

• Tanveer Mahamadali Shaikh and
• Fung-E Hong

Beilstein J. Org. Chem. 2013, 9, 1578–1588, doi:10.3762/bjoc.9.180

• (2t) afforded the corresponding coupled products in moderate yields, respectively (Table 4, entries 9–12). To expand the scope of this cross-coupling, these conditions were then applied to a variety of boronic acids and styrene (Table 5). For a diverse set of boronic acids, cross-coupling proceeded

Coupling of C-nitro-NH-azoles with arylboronic acids. A route to N-aryl-C-nitroazoles

• Marta K. Kurpet,
• Aleksandra Dąbrowska,
• Małgorzata M. Jarosz,
• Katarzyna Kajewska-Kania,
• Nikodem Kuźnik and
• Jerzy W. Suwiński

Beilstein J. Org. Chem. 2013, 9, 1517–1525, doi:10.3762/bjoc.9.173

• substrates such as amines, amides, imides or heterocycles with boronic acids, the method has become a powerful synthetic route for N-arylation. Many investigations concerning the influence of the amount and kind of a catalyst, type of solvent, temperature, the presence of a base, and other reaction

• efficient N-arylating system for phenylboronic acid, we expanded the scope of this reaction by exploring a variety of boronic acids with different substitution patterns. The investigated compounds brought such substituents as F, Cl, CH3, OCH3, OCF3, and NO2 (Scheme 3). The results show that an electron

Conformational analysis and intramolecular interactions in monosubstituted phenylboranes and phenylboronic acids

• Josué M. Silla,
• Rodrigo A. Cormanich,
• Roberto Rittner and
• Matheus P. Freitas

Beilstein J. Org. Chem. 2013, 9, 1127–1134, doi:10.3762/bjoc.9.125

• transpeptidases [1][2]. Other important studies incorporate the boronic acid moiety into amino acids and nucleosides as antitumor and antiviral agents [3][4]. Indeed, the great importance of aromatic boronic acids to biological and pharmaceutical purposes has been reported, as well as the interest to introduce a

Palladium-catalyzed substitution of (coumarinyl)methyl acetates with C-, N-, and S-nucleophiles

• Kalicharan Chattopadhyay,
• Erik Fenster,
• Alexander J. Grenning and
• Jon A. Tunge

Beilstein J. Org. Chem. 2012, 8, 1200–1207, doi:10.3762/bjoc.8.133

• partner, modifications including fluoro and alkyl substitution were tolerated. In addition to aryl boronic acids (3a–c), the reaction was also extended to couplings of vinyl boronic acids having varied electronic properties (3d–e). As before, various simple substitutions and electronic changes were

Synthesis of new pyrrole–pyridine-based ligands using an in situ Suzuki coupling method

• Matthias Böttger,
• Björn Wiegmann,
• Steffen Schaumburg,
• Peter G. Jones,
• Wolfgang Kowalsky and
• Hans-Hermann Johannes

Beilstein J. Org. Chem. 2012, 8, 1037–1047, doi:10.3762/bjoc.8.116

• acid for the Suzuki coupling. Crystals of the products could be grown and exhibited interesting structures by X-ray analysis, one of them showing a chain-like network with the adjacent molecules linked to each other via intermolecular N–H…N hydrogen bonds. Keywords: boronic acids; complex chemistry

Pseudo five-component synthesis of 2,5-di(hetero)arylthiophenes via a one-pot Sonogashira–Glaser cyclization sequence

• Dominik Urselmann,
• Dragutin Antovic and
• Thomas J. J. Müller

Beilstein J. Org. Chem. 2011, 7, 1499–1503, doi:10.3762/bjoc.7.174

• [3], were easily accessed in a one-pot procedure. Starting from the stable and readily available aryliodides 1n and 1o, the presented new methodology allowed the synthesis of both molecules in a quick, simple and economic one-pot reaction. Moreover, the usual preparation and isolation of boronic

• acids or even more sensitive zinc organometallics was circumvented. In addition the use of the rather expensive diiodothiophene as a coupling partner was avoided [24][25][26]. “PPTPP” (2n) and “T5” (2o) were readily purified by Soxhlet extraction. Upon reaction of N-Boc-3-iodoindole (1p) a complete

Amines as key building blocks in Pd-assisted multicomponent processes

• Didier Bouyssi,
• Nuno Monteiro and
• Geneviève Balme

Beilstein J. Org. Chem. 2011, 7, 1387–1406, doi:10.3762/bjoc.7.163

• block the ring closure (Scheme 12) [11]. Homoallylic amines and α-aminoesters 24 were prepared by Malinakova and coworkers, by a palladium(II)-catalyzed coupling of boronic acids, 1,2-nonadiene, and aliphatic, aromatic or heteroaromatic imines [12]. The authors postulated a transmetalation step between

Synthesis of diverse dihydropyrimidine-related scaffolds by fluorous benzaldehyde-based Biginelli reaction and post-condensation modifications

• Bruno Piqani and
• Wei Zhang

Beilstein J. Org. Chem. 2011, 7, 1294–1298, doi:10.3762/bjoc.7.150

• with four boronic acids yielded 5-biaryl-5H-thiazolo[3,2-a]pyrimidines 6a–h in 55–64% yields after F-SPE and flash chromatography purifications (Table 2). Dihydropyrimidinethione 4f was used for the Liebeskind–Srogl coupling reaction with a phenylboronic acid to convert to 2-aryl-1,6-dihydropyrimidine

• Suzuki coupling reactions with four boronic acids to yield 2-aryl-6-biaryl substituted dihydropyrimidines 7a–d after F-SPE and flash chromatography purifications (Table 3). Conclusion We have developed a new application of perfluorooctanesulfonyl-attached benzaldehydes for the diversity-oriented

Studies on Pd/NiFe₂O₄ catalyzed ligand-free Suzuki reaction in aqueous phase: synthesis of biaryls, terphenyls and polyaryls

• Sanjay R. Borhade and
• Suresh B. Waghmode

Beilstein J. Org. Chem. 2011, 7, 310–319, doi:10.3762/bjoc.7.41

• , but the conversion was too low to be of practical use. Using the preliminary optimized reaction conditions, we explored the general applicability of Pd/NiFe2O4 catalyst with various boronic acids and aryl halides containing electron withdrawing or donating substituents (Table 4). The Pd/NiFe2O4

• short reaction times. Bromobenzene and electron rich aryl bromides required a higher loading of palladium (1.0 mol %) to give comparable results. Both electron rich and electron deficient arylboronic acids gave biaryl products in good to excellent yields. Heterocyclic boronic acids required longer

Palladium- and copper-mediated N-aryl bond formation reactions for the synthesis of biological active compounds

• Carolin Fischer and
• Burkhard Koenig

Beilstein J. Org. Chem. 2011, 7, 59–74, doi:10.3762/bjoc.7.10

• Buchwald [6][7] and Hartwig [8][9] has been a major breakthrough in this field. More recently, Chan [10] and Lam [11][12] introduced the copper-mediated arylation of N-nucleophiles using stoichiometric copper(II) acetate and boronic acids. Collman improved the procedure using catalytic amounts of [Cu(OH

• biologically active molecules A key intermediate (88) for the potent matrix metalloproteases (MMPs) inhibitor AG3433 (89) was synthesized by coupling an electron-deficient pyrrole (86) with an arylboronic acid (87) in excellent yield (93%, Scheme 21). Screening numerous boronic acids it was found that only

• boronic acids containing electron-donating or weakly electron-withdrawing substituents were suitable. Pyrroles lacking a substituent in the 2-position, which is supposed to support the reaction by a chelating effect with the copper ion, did not succeed in the coupling reaction. Further disadvantages were

Syntheses and properties of thienyl-substituted dithienophenazines

• Annemarie Meyer,
• Eva Sigmund,
• Friedhelm Luppertz,
• Gregor Schnakenburg,
• Immanuel Gadaczek,
• Thomas Bredow,
• Stefan-S. Jester and
• Sigurd Höger

Beilstein J. Org. Chem. 2010, 6, 1180–1187, doi:10.3762/bjoc.6.135

• coupling products with thiophene boronic acids. In both cases the thiophene units of the molecules act as electron rich parts (donors, D), whereas the phenazine moieties serve as electron deficient parts (acceptors, A), leading to a bathochromic shift of the UV–vis spectra in comparison with the non

• and could be more easily purified by column chromatography. Nevertheless, both compounds can serve as starting materials for thiophene oligomers with increased donor ability. Thiophene- and bithiophene boronic acids or esters were coupled via Suzuki–Miyaura reactions forming orange-colored thiophene

• soluble compounds (20–50 mg/mL in chloroform or dichlorobenzene) were obtained by coupling of the hexyl substituted compounds 10b and 11b with alkyl substituted thiophene or bithiophene boronic acids (esters). UV–Vis spectra Figure 1a shows the UV–Vis absorption and emission spectra of 12a, 13, 14 and 15

Suzuki–Miyaura cross-coupling reaction of 1-aryltriazenes with arylboronic acids catalyzed by a recyclable polymer-supported N-heterocyclic carbene–palladium complex catalyst

• Guangming Nan,
• Fang Ren and
• Meiming Luo

Beilstein J. Org. Chem. 2010, 6, No. 70, doi:10.3762/bjoc.6.70

• procedure [31] (Scheme 1). The Pd loading was determined to be 0.1 mmol/g by inductively coupled plasma-atomic emission spectrometry (ICP-AES). The Suzuki–Miyaura cross-coupling of 1-aryltriazenes and boronic acids catalyzed by the polymer-supported Pd–NHC catalyst 1 was investigated in detail with the