Synthesis, characterization and DNA interaction studies of new triptycene derivatives

• Sourav Chakraborty,
• Snehasish Mondal,
• Rina Kumari,
• Sourav Bhowmick,
• Prolay Das and
• Neeladri Das

Beilstein J. Org. Chem. 2014, 10, 1290–1298, doi:10.3762/bjoc.10.130

• tribromotriptycenes as synthons [36], syntheses of triethynyltriptycenes (TETs) 1 and 2 were efficiently realized in two steps (Scheme 1). In the presence of Pd(0) catalyst and cuprous iodide (cocatalyst), Sonogashira cross-coupling reaction of 2,6,14-tribromotriptycene with 3.0 equiv of (trimethylsilyl)acetylene in

A new building block for DNA network formation by self-assembly and polymerase chain reaction

• Holger Bußkamp,
• Sascha Keller,
• Marta Robotta,
• Malte Drescher and
• Andreas Marx

Beilstein J. Org. Chem. 2014, 10, 1037–1046, doi:10.3762/bjoc.10.104

• branching molecules. The synthesis strategy was designed to meet the requirements of standard DNA solid support synthesis. Stepwise Sonogashira reaction was employed using the higher reactivity of iodide in the presence of bromide within 1,3-dibromo-5-iodobenzene (1) employing the known compounds 2 [41] and

The influence of intraannular templates on the liquid crystallinity of shape-persistent macrocycles

• Joscha Vollmeyer,
• Ute Baumeister and
• Sigurd Höger

Beilstein J. Org. Chem. 2014, 10, 910–920, doi:10.3762/bjoc.10.89

• Supporting Information File 1). Then 6 is attached to 5 in a fourfold Sonogashira–Hagihara reaction. To compensate the acetylene dimerization side reaction, the acetylene is added in 25% excess. Fluoride-induced removal of the silyl protecting groups yields the precursor 7. With Pd(PPh3)2Cl2 and CuI as

Molecular recognition of isomeric protonated amino acid esters monitored by ESI-mass spectrometry

• Andrea Liesenfeld and
• Arne Lützen

Beilstein J. Org. Chem. 2014, 10, 825–831, doi:10.3762/bjoc.10.78

• , followed by hydrolysis to afford phenol 6 which was finally transferred into the corresponding triflate 7 in 64% yield (Scheme 1). Triflate 7 was then subjected to a Sonogashira cross-coupling reaction and a Suzuki cross-coupling reaction followed by treatment with boron tribromide to obtain the

Staudinger ligation towards cyclodextrin dimers in aqueous/organic media. Synthesis, conformations and guest-encapsulation ability

• Malamatenia D. Manouilidou,
• Yannis G. Lazarou,
• Irene M. Mavridis and
• Konstantina Yannakopoulou

Beilstein J. Org. Chem. 2014, 10, 774–783, doi:10.3762/bjoc.10.73

• . These include the well-known copper-catalyzed azide–alkyne cyclization (CuAAC, “click” reaction) between an azido-CD derivative and an alkyne linker [19][22][23][24] [22], or vice versa, the metal catalyzed reactions between propargyl-CDs and aryl dihalides such as the Sonogashira and Glaser–Hay

Rapid pseudo five-component synthesis of intensively blue luminescent 2,5-di(hetero)arylfurans via a Sonogashira–Glaser cyclization sequence

• Fabian Klukas,
• Alexander Grunwald,
• Franziska Menschel and
• Thomas J. J. Müller

Beilstein J. Org. Chem. 2014, 10, 672–679, doi:10.3762/bjoc.10.60

• in a pseudo five-component reaction via a Sonogashira–Glaser coupling sequence followed by a superbase-mediated (KOH/DMSO) cyclization in a consecutive one-pot fashion. Besides the straightforward synthesis of natural products and biologically active molecules all representatives are particularly

• approach are clearly the extended reaction times (3–6 d) and the removal of the catalyst after the coupling step. Recently, we became particularly interested in sequentially Pd-catalyzed processes [35] starting from (hetero)aryl iodides [36]. In particular, the Pd–Cu-catalyzed Sonogashira–Glaser sequence

• Sonogashira–Glaser sequence we recently presented a straightforward one-pot sequence for the synthesis of 2,5-di(hetero)arylthiophenes [38]. Here, we report the methodological development of a novel multicomponent synthesis of symmetrical 2,5-(hetero)arylfurans in the sense of a consecutive one-pot sequence

One-pot three-component synthesis and photophysical characteristics of novel triene merocyanines

• Christian Muschelknautz,
• Robin Visse,
• Jan Nordmann and
• Thomas J. J. Müller

Beilstein J. Org. Chem. 2014, 10, 599–612, doi:10.3762/bjoc.10.51

• -enylidene and 4-(1,3,3-trimethylindolin-2-ylidene)but-2-en-1-ylideneindolones are obtained in good to excellent yields in a consecutive three-component insertion Sonogashira coupling–addition sequence. The selectivity of either series is remarkable and has its origin in the stepwise character of the

• -iodoanilides 5a and terminal arylalkynes 6 at room temperature under Sonogashira conditions forming ynylideneindolones as intermediates (the reaction was monitored by TLC to ensure complete conversion) [30][31][32], which were not isolated, an ethanolic solution of Fischer’s base (7) was added and reacted at

• experimentally determined very similar diastereomeric distribution of the 1-styryleth-2-enylideneindolones 8. Interestingly, upon coupling of the N-tosyl-substituted alkynoyl o-iodoanilides 5b and 5c with terminal arylalkynes 6 at room temperature under Sonogashira conditions and reacting the ynylideneindolone

Practical synthesis of aryl-2-methyl-3-butyn-2-ols from aryl bromides via conventional and decarboxylative copper-free Sonogashira coupling reactions

• Andrea Caporale,
• Stefano Tartaggia,
• Andrea Castellin and
• Ottorino De Lucchi

Beilstein J. Org. Chem. 2014, 10, 384–393, doi:10.3762/bjoc.10.36

• bromides rather than expensive iodides and using 4 or propiolic acid rather than TMS-acetylene as inexpensive alkyne sources are described. Keywords: alkynes; decarboxylative couplings; Erlotinib; palladium; propiolic acid; Introduction The Sonogashira coupling reaction of aryl or alkenyl halides with

• ][11][12][13]. The Sonogashira coupling reaction is usually carried out under Pd/Cu catalysis, in which the palladium has the function to promote the cross-coupling of an aryl fragment, added via oxidative addition of the corresponding halide, with an alkynyl residue to provide a disubstituted

• complicates the recycling of the palladium catalyst since the two metals are difficult to separate. Sonogashira reactions can be used for the syntheses of terminal alkynes from aryl halides through the coupling with an alkyne source such as trimethylsilylacetylene (TMSA) or 2-methyl-3-butyn-2-ol (4) in

Synthesis of 3,4-dihydro-1,8-naphthyridin-2(1H)-ones via microwave-activated inverse electron-demand Diels–Alder reactions

• Salah Fadel,
• Youssef Hajbi,
• Mostafa Khouili,
• Said Lazar,
• Franck Suzenet and
• Gérald Guillaumet

Beilstein J. Org. Chem. 2014, 10, 282–286, doi:10.3762/bjoc.10.24

• electron-demand Diels–Alder reaction from 1,2,4-triazines bearing an acylamino group with a terminal alkyne side chain. Alkynes were first subjected to the Sonogashira cross-coupling reaction with aryl halides, the product of which then underwent an intramolecular inverse electron-demand Diels–Alder

• reaction to yield 5-aryl-3,4-dihydro-1,8-naphthyridin-2(1H)-ones by an efficient synthetic route. Keywords: inverse-electron-demand Diels–Alder reaction; microwave irradiation; naphthyridin-2(1H)-ones; Sonogashira cross-coupling; 1,2,4-triazine; Introduction 1,8-Naphthyridine derivatives are an important

• envisaged to evaluate the reactivity of internal alkynes towards the inverse electron-demand Diels–Alder reaction. To reach this goal, we decided to functionalize the alkynes 6–9 employing the Sonogashira cross-coupling reaction. Preparation of aryl-N-triazinylpentynamides The terminal alkynes 6–9 were then

Synthesis of new enantiopure poly(hydroxy)aminooxepanes as building blocks for multivalent carbohydrate mimetics

• Léa Bouché,
• Maja Kandziora and
• Hans-Ulrich Reissig

Beilstein J. Org. Chem. 2014, 10, 213–223, doi:10.3762/bjoc.10.17

• reduction of the carbonyl group [43] and TBS cleavage, propargylic ether 18 was obtained (88% yield over two steps) [44]. The alkyne moiety provides options for further transformations, e.g. Sonogashira reactions, Glaser couplings or 1,3-dipolar cycloadditions (click reactions) [45]. We were also interested

Total synthesis of the endogenous inflammation resolving lipid resolvin D2 using a common lynchpin

• John Li,
• May May Leong,
• Alastair Stewart and
• Mark A. Rizzacasa

Beilstein J. Org. Chem. 2013, 9, 2762–2766, doi:10.3762/bjoc.9.310

• . Desilylation of 11 followed by hydrozirconation and iodination gave the vinyl iodide 4 and Sonogashira coupling between this compound and enyne 3 provided alkyne 18. Acetonide deprotection, partial reduction and ester hydrolysis then gave resolvin D2 (1). Keywords: catalysis; eicosanoid; natural product

• ; resolvin D2; Sonogashira coupling; total synthesis; Wittig reaction; Introduction The resolution of inflammation is a tightly governed active process effectively mediated by a range of bioactive polyunsaturated fatty acids, peptides and proteins. In 2002, a new family of endogenously generated lipid

• can produce useful amounts of this important compound as well as novel isomers. Results and Discussion Retrosynthetic analysis A retrosynthetic analysis of RvD2 (1) is shown in Scheme 1. It was envisaged that the target compound 1 could be secured via a Sonogashira coupling to form the C11–C12 bond

Synthesis of enones, pyrazolines and pyrrolines with gem-difluoroalkyl side chains

• Assaad Nasr El Dine,
• Ali Khalaf,
• Danielle Grée,
• Olivier Tasseau,
• Fares Fares,
• Nada Jaber,
• Philippe Lesot,
• Ali Hachem and
• René Grée

Beilstein J. Org. Chem. 2013, 9, 1943–1948, doi:10.3762/bjoc.9.230

• –Miyaura coupling [35] gave biphenyl derivative 7e in 82% yield, while the Heck [36] and Sonogashira [37] reactions afforded also the desired targets 8e and 9e in 72% and 77% yield respectively. Similar results were obtained in Pd-mediated reactions starting from pyrroline 6e, as indicated in Scheme 8. The

A reductive coupling strategy towards ripostatin A

• Kristin D. Schleicher and
• Timothy F. Jamison

Beilstein J. Org. Chem. 2013, 9, 1533–1550, doi:10.3762/bjoc.9.175

• Takai olefination [36] was used to generate the E-vinyl iodide. The vinyl iodide was sufficiently stable for purification by silica gel chromatography but, following purification, was immediately carried forward to a Sonogashira reaction with propyne [37]. The enyne could be obtained in 15:1 E/Z

Practical synthesis of indoles and benzofurans in water using a heterogeneous bimetallic catalyst

• Cybille Rossy,
• Eric Fouquet and
• François-Xavier Felpin

Beilstein J. Org. Chem. 2013, 9, 1426–1431, doi:10.3762/bjoc.9.160

• /bjoc.9.160 Abstract This paper describes the preparation of indoles, azaindoles and benzofurans in pure water by using a new heterogeneous Pd–Cu/C catalyst through a cascade Sonogashira alkynylation–cyclization sequence. Details of the optimization studies and the substrate scope are discussed. This

• ][7]. A detailed survey of the recent literature revealed that both indoles and benzofurans can be attained by a cascade Sonogashira alkynylation–cyclization sequence (Scheme 1). Many efficient catalytic systems have been reported since the pioneering studies of Yamanaka [8] and this approach is now a

• describe the use of a readily available heterobimetallic Pd–Cu/C catalyst for cascade Sonogashira alkynylation–cyclization sequences in pure water leading to indoles, azaindoles and benzofurans. Results and Discussion We recently reported a simple and efficient procedure for preparing a very active

Synthesis, photophysical and electrochemical characterization of terpyridine-functionalized dendritic oligothiophenes and their Ru(II) complexes

• Amaresh Mishra,
• Elena Mena-Osteritz and
• Peter Bäuerle

Beilstein J. Org. Chem. 2013, 9, 866–876, doi:10.3762/bjoc.9.100

• Amaresh Mishra Elena Mena-Osteritz Peter Bauerle Institute of Organic Chemistry II and Advanced Materials, Ulm University, Albert-Einstein-Allee 11, 89081 Ulm, Germany 10.3762/bjoc.9.100 Abstract Pd-catalyzed Sonogashira cross-coupling reactions were used to synthesize novel π-conjugated

• Syntheses. A modular approach was selected for the synthesis of the targeted metallodendrimers, consisting of (1) the preparation of dendrons by employing Sonogashira cross-coupling reactions, (2) their functionalization with tpy-ligands, and (3) formation of the corresponding homoleptic Ru(II) complexes

• ':6',2''-terpyridine (4) [47], which was readily deprotected by CsF in methanol to give the targeted 4'-ethynyl-2,2':6',2''-terpyridine (5) (Scheme 1). Cross-coupling of ethynylated tpy building block 5 with iodinated G1-dendron 6 and G2-dendron 7 [42] under standard Sonogashira-type coupling

Some aspects of radical chemistry in the assembly of complex molecular architectures

• Béatrice Quiclet-Sire and
• Samir Z. Zard

Beilstein J. Org. Chem. 2013, 9, 557–576, doi:10.3762/bjoc.9.61

• starting xanthate. For instance, a regioselective Sonogashira coupling leading to compound 57 may be performed without affecting the less reactive chlorine substituent. The annelation commencing with xanthate 58 and furnishing indole derivative 59, an advanced intermediate in the formal synthesis of

Efficient synthesis of phenylene-ethynylene rods and their use as rigid spacers in divalent inhibitors

• Francesca Pertici,
• Norbert Varga,
• Arnoud van Duijn,
• Matias Rey-Carrizo,
• Anna Bernardi and
• Roland J. Pieters

Beilstein J. Org. Chem. 2013, 9, 215–222, doi:10.3762/bjoc.9.25

• , Universita’ degli Studi di Milano, via Golgi 19, 20133 Milano, Italy 10.3762/bjoc.9.25 Abstract The synthesis of phenylene-ethynylene rods and their use as rigid spacers is described. Alternation of a Sonogashira reaction and silyl group cleavage was used to obtain rigid spacers with even and odd numbers of

• ; rigid spacers; Sonogashira reaction; Introduction Linker or spacer molecules have a wide range of applications in many areas of chemistry as bridging molecules between separate functional units. Spacers are often flexible but depending on the nature of the application, efforts have been made to make

• deprotection needed to make B. Its free alkyne moiety can undergo a Sonogashira reaction with C to give D. At this point the removal of the protecting group R1 and R2 can be performed, to either couple the ligands or elongate the system by a double Sonogashira reaction. The strategy to prepare spacers

Dipyrazolo[1,5-a:4',3'-c]pyridines – a new heterocyclic system accessed via multicomponent reaction

• Wolfgang Holzer,
• Gytė Vilkauskaitė,
• Eglė Arbačiauskienė and
• Algirdas Šačkus

Beilstein J. Org. Chem. 2012, 8, 2223–2229, doi:10.3762/bjoc.8.251

• formylation (with concomitant transformation of the oxygen into a chlorine substituent), followed by Sonogashira cross-coupling reaction of the obtained 5-chloropyrazole-4-carbaldehydes with appropriate alkynes, has been described by us in a former publication [21]. Compounds 1 containing an alkyne function

Highly stereocontrolled synthesis of trans-enediynes via carbocupration of fluoroalkylated diynes

• Tsutomu Konno,
• Misato Kishi and
• Takashi Ishihara

Beilstein J. Org. Chem. 2012, 8, 2207–2213, doi:10.3762/bjoc.8.249

• in situ generated vinylcuprates could react very smoothly with an excess amount of iodine, the vinyl iodides being obtained in high yields. Thus-obtained iodides underwent a very smooth Sonogashira cross-coupling reaction to afford various trans-enediynes in high yields. Keywords: carbocupration

• PPh3 and CuI in DMF at room temperature for 24 h, gave the corresponding Sonogashira cross-coupling products 3a–e in good to high yields [24][25][26] (Scheme 2). Subsequently, 3a was subjected to the usual β-elimination conditions according to the literature [23][27][28][29], i.e., treatment of 3a with

• stereoselective manner. Finally, we attempted the Sonogashira cross-coupling reaction of the obtained iodide 13a (Scheme 4). Thus, treatment of 13a with 1.2 equiv of terminal alkynes and 40 equiv of Et3N in the presence of 10 mol % each of Pd(PPh3)4 and CuI in THF at 70 °C for 2–5 h gave the corresponding

Synthesis of diverse indole libraries on polystyrene resin – Scope and limitations of an organometallic reaction on solid supports

• Kerstin Knepper,
• Sylvia Vanderheiden and
• Stefan Bräse

Beilstein J. Org. Chem. 2012, 8, 1191–1199, doi:10.3762/bjoc.8.132

• results in the liquid phase, ortho,ortho-unsubstituted nitroarenes also delivered indole moieties in good yields. Subsequent palladium-catalyzed reactions (Suzuki, Heck, Sonogashira, Stille) delivered, after cleavage, the desired molecules in moderate to good yields over four steps. The scope and

• are given in Scheme 3. Again, these reactions proceeded smoothly. We also performed Sonogashira–Hagihara reactions on solid supports. This reaction gave rise to alkynyl-substituted indoles. It should be noted at this point that the basic cleavable linker prevents the addition of water usually observed

• dried in high vacuum. The loading of the resulting resin was calculated as if complete conversion had taken place. GP 4 - Sonogashira–Hagihara reaction: Under an argon atmosphere, one equiv of the respective 7-bromo-1H-indole-6-carboxymethyl-polystyrene is suspended in DMF (0.1 mmol/mL) together with

Asymmetric total synthesis of smyrindiol employing an organocatalytic aldol key step

• Dieter Enders,
• Jeanne Fronert,
• Tom Bisschops and
• Florian Boeck

Beilstein J. Org. Chem. 2012, 8, 1112–1117, doi:10.3762/bjoc.8.123

• an acetonide, whereupon lactonization would take place simultaneously. Alkyne 5 could be synthesized through a Sonogashira coupling with iodide 6. This acetonide could be formed by addition of a methyl anion equivalent to the carbonyl group of the aldol product 7 with subsequent protection of the 1,3

• benzofuran system; thus, for further modifications it was protected as acetonide 16 in a moderate yield (66%) using 2,2-dimethoxypropane under PPTA catalysis. As we turned towards the Sonogashira reaction of the iodide 16 with a propiolic acid derivative, we found that the allyl protecting group was cleaved

• readily by the palladium present in the reaction mixture. Since the Sonogashira reaction did not occur with the unprotected ortho-iodophenol 17, we decided to reprotect the phenol as a tert-butyldimethylsilyl (TBS) ether, using TBS chloride and DBU. Reprotection was necessary, since employing the TBS

On the bromination of the dihydroazulene/vinylheptafulvene photo-/thermoswitch

• Virginia Mazzanti,
• Martina Cacciarini,
• Søren L. Broman,
• Christian R. Parker,
• Magnus Schau-Magnussen,
• Andrew D. Bond and
• Mogens B. Nielsen

Beilstein J. Org. Chem. 2012, 8, 958–966, doi:10.3762/bjoc.8.108

• optical and redox properties [13]. The two bromo positions of 14 showed very different reactivity. Thus, subjecting 14 to a Sonogashira coupling with triisopropylsilylacetylene by using the Pd(PPh3)2Cl2/CuI catalyst system only gave the monocoupled product 15 (Scheme 7), confirmed by X-ray crystal

• former substitution enhances the ring closure while the latter retards it. The new bromo-substituted compounds will be interesting for future scaffolding in the quest for advanced photo- and thermoswitches. We note, however, that initial attempts at using the 3-bromo-substituted DHA for Sonogashira or

• Suzuki couplings (as previously accomplished for the 7-bromo-substituted DHA) have so far been unsuccessful. It seems that the 3-bromo functionality is not very reactive, which is reflected as well by the regioselective Sonogashira and Suzuki reactions on the 3,7-dibromoazulene 14 reported in this work

Diarylethene-modified nucleotides for switching optical properties in DNA

• Sebastian Barrois and
• Hans-Achim Wagenknecht

Beilstein J. Org. Chem. 2012, 8, 905–914, doi:10.3762/bjoc.8.103

• ) is based on Sonogashira-type cross couplings as key steps [51] to attach the photoactive chromophore to the nucleoside. For the synthesis of the first nucleoside 4 (Scheme 2), commercially available 5-bromobenzothiazole (7) is deprotonated with LDA and methylated by methyl iodide in quantitative

• diarylethene-modified nucleoside 4 then continues by cleavage of the TMS protecting group of 11 with K2CO3 in MeOH. Finally, the synthesis is concluded by the Sonogashira-type coupling of diarylethene 13 to 5-iodo-2’-deoxyuridine (14) in 65% yield. For the second and third modified nucleosides 5 and 6, the

• last two synthetic steps are similar to those for nucleoside 4. Deprotection of 12 gave the doubly ethinylated diarylethene 15 in quantitative yield. The subsequent Sonogashira coupling with 14 at rt gave the mono-nucleosidic product 5 in 23% yield, and at 60 °C the di-nucleosidic product 6 in 35

Thiophene-based donor–acceptor co-oligomers by copper-catalyzed 1,3-dipolar cycloaddition

• Stefanie Potratz,
• Amaresh Mishra and
• Peter Bäuerle

Beilstein J. Org. Chem. 2012, 8, 683–692, doi:10.3762/bjoc.8.76

• extensively investigated organic semiconducting materials used in organic electronics [1][2][3]. In this respect, various oligomers have been developed by using metal-catalyzed Suzuki-, Stille-, Sonogashira-, and Kumada-type cross-coupling reactions [4][5][6][7][8][9]. On the other hand, the so-called “click

Sonogashira–Hagihara reactions of halogenated glycals

• Dennis C. Koester and
• Daniel B. Werz

Beilstein J. Org. Chem. 2012, 8, 675–682, doi:10.3762/bjoc.8.75

• Dennis C. Koester Daniel B. Werz Institut für Organische und Biomolekulare Chemie, Georg-August-Universität Göttingen, Tammannstr. 2, 37077 Göttingen, Germany 10.3762/bjoc.8.75 Abstract Herein, we report on our findings of the Sonogashira–Hagihara reaction with 1-iodinated and 2-brominated

• substituent in position 2. Keywords: C-glycosides; enyne; glycals; reductive/oxidative refunctionalization; Sonogashira–Hagihara reaction; Introduction Carbohydrates are key players in a plethora of biological processes, such as cell-development, metastasis, cell–cell aggregation and viral infection [1][2

• been no in-depth study of the synthesis of 1- and 2-alkynylated glycals by means of the Sonogashira–Hagihara reaction to date. Herein, we wish to report on our findings with respect to the reaction of persilylated 1-iodoglucal 7 and peracetylated 2-bromogalactal 10 with readily available alkynes 8a–8h