Branching out at C-2 of septanosides. Synthesis of 2-deoxy-2-C-alkyl/aryl septanosides from a bromo-oxepine

• Supriya Dey and
• Narayanaswamy Jayaraman

Beilstein J. Org. Chem. 2012, 8, 522–527, doi:10.3762/bjoc.8.59

• acceptor moieties in C–C bond forming Heck, Suzuki and Sonogashira coupling reactions, thus affording 2-deoxy-2-C-alkyl/aryl septanosides. Whereas Heck and Sonogashira coupling reactions afforded 2-deoxy-2-C-alkenyl and -alkynyl derivatives, respectively, the Suzuki reaction afforded 2-deoxy-2-C-aryl

• , Heck, Suzuki and Sonogashira coupling reactions. Heck coupling reactions [24][25] were undertaken first. Thus, the reaction of bromo-oxepine 2 with methyl acrylate was performed, in the presence of Pd(OAc)2 (10 mol %) and Cs2CO3 in 1,4-dioxane, at 98 °C (Scheme 1), to afford diene 3, in 70% yield. The

• bromo-oxepine 2, efforts were undertaken to implement C–C bond forming Suzuki and Sonogashira coupling reactions. Suzuki reactions were undertaken by involving phenylboronic acid and substituted phenylboronic acids [26][27], in the presence of Pd(OAc)2 (10 mol %) and Cs2CO3 in 1,4-dioxane at 98 °C

Syntheses and applications of furanyl-functionalised 2,2’:6’,2’’-terpyridines

• Jérôme Husson and
• Michael Knorr

Beilstein J. Org. Chem. 2012, 8, 379–389, doi:10.3762/bjoc.8.41

• provide lanthanide complexes 56 and 57 (Scheme 10). The bromo-derivative 54 was further functionalised by cross-coupling reactions. Namely, the treatment of 54 with aminophenylacetylene in a Sonogashira reaction afforded terpyridine 58. The triple bond was then reduced by hydrogenation providing tpy 59

• used as a starting material and reacted with trimethylsilyl acetylene in a Sonogashira reaction. After deprotection of the trimethylsilyl moiety with tetrabutylammonium fluoride, terpyridine 63 was obtained. Reaction of the latter with 3-azidopropanol afforded the triazinyl-containing compound 64

Synthesis of multivalent host and guest molecules for the construction of multithreaded diamide pseudorotaxanes

• Nora L. Löw,
• Egor V. Dzyuba,
• Boris Brusilowskij,
• Lena Kaufmann,
• Elisa Franzmann,
• Wolfgang Maison,
• Emily Brandt,
• Daniel Aicher,
• Arno Wiehe and
• Christoph A. Schalley

Beilstein J. Org. Chem. 2012, 8, 234–245, doi:10.3762/bjoc.8.24

• Berlin, Germany 10.3762/bjoc.8.24 Abstract A series of di-, tri- and tetravalent axles and wheels for the synthesis of pseudorotaxanes bearing the tetralactam macrocycle/diamide axle binding motif was prepared. Starting from iodinated monovalent precursors, Sonogashira cross-coupling reactions were

• wheel precursors. Keywords: multivalency; pseudorotaxanes; Sonogashira coupling; supramolecular chemistry; tetralactam macrocycles; Introduction Synthetic supramolecular complexes have the great potential to put those concepts to the test that govern much of the noncovalent chemistry in nature. Among

• (wheel)N–H···O=C(axle) hydrogen bonds. Through the iodine substituents, both building blocks can be connected to appropriate spacers in Sonogashira cross-coupling reactions [102]. This coupling strategy creates rather rigid connections to the spacers and helps in reducing the entropic penalties that

Imidazole as a parent π-conjugated backbone in charge-transfer chromophores

• Jiří Kulhánek and
• Filip Bureš

Beilstein J. Org. Chem. 2012, 8, 25–49, doi:10.3762/bjoc.8.4

• chromophores 95–100 (Figure 18; [112]). The synthesis of this series of chromophores involved two-fold Suzuki–Miyaura and Sonogashira cross-coupling reactions on dibromoolefin 94 (for X-ray structure see [113]). This compound proved to be a very useful, fully planar precursor for the construction of a

• –111 (Figure 19; [20]). In contrast to a typical synthetic approach to diimidazoles as shown in Scheme 1, we used 4,5-dicyanoimidazole derivatives 1–3 (Scheme 2) and modern direct arylation, Suzuki–Miyaura, Sonogashira, and Heck reactions to construct molecules 101–111. These chromophores possess two

Impact of the level of complexity in self-sorting: Fabrication of a supramolecular scalene triangle

• Kingsuk Mahata and
• Michael Schmittel

Beilstein J. Org. Chem. 2011, 7, 1555–1561, doi:10.3762/bjoc.7.183

• ] (Figure 1). The coordination behaviour of molecular component 3 was integrated into 5, the latter being synthesised in a Sonogashira homocoupling reaction [27]. The information stored in 1 and 4 was instated in the unsymmetrical bisphenanthroline 6, readily accessible by stepwise Sonogashira cross

Synthesis of fluoranthenes by hydroarylation of alkynes catalyzed by gold(I) or gallium trichloride

• Sergio Pascual,
• Christophe Bour,
• Paula de Mendoza and
• Antonio M. Echavarren

Beilstein J. Org. Chem. 2011, 7, 1520–1525, doi:10.3762/bjoc.7.178

• lithium with the corresponding propargyl bromide or by Sonogashira couplings of 9-(prop-2-ynyl)-9H-fluorene [61], were cyclized by using gold(I) complex 6 or GaCl3 as the catalyst (Table 3). Although both catalysts could be used for the synthesis of 3-arylfluoranthenes 8b–h, better yields were obtained

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

• Dominik Urselmann Dragutin Antovic Thomas J. J. Muller Institut für Organische Chemie und Makromolekulare Chemie, Heinrich-Heine-Universität Düsseldorf, Universitätsstr. 1, D-40225 Düsseldorf, Germany 10.3762/bjoc.7.174 Abstract Based upon a consecutive one-pot Sonogashira–Glaser coupling

• efficiency is also variable. Just recently we reported a very straightforward one-pot synthesis of symmetric 1,4-di(hetero)arylated 1,3-butadiynes starting from (hetero)aryl iodides by virtue of a sequentially Pd/Cu-catalyzed [14] Sonogashira–Glaser process (Scheme 1) [15]. According to this general one-pot

• Sonogashira–Glaser cyclization sequence. Results and Discussion The conversion of 1,4-diaryl-1,3-butadiynes into 2,5-diarylthiophenes by base-mediated cyclization with sodium sulfide or sodium hydrogen sulfide is a literature-known procedure [16][17][18][19][20][21][22][23]. Therefore, we reasoned that the

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

• reported by Wu and coworkers. Initial Sonogashira coupling was effected between a 2-bromobenzaldehyde and an alkyne in the presence of catalytic amounts of PdCl2(PPh3)2 and CuI. After complete conversion of the aldehyde into the coupling product 25 (TLC control), a primary amine and diethylphosphite were

• ,β-unsaturated ketones generated in situ by Pd-catalyzed Sonogashira cross-coupling reactions. For instance, by building on their expertise in this area [14] Müller and coworkers recently developed a very effective and modular three-component strategy to assemble a series of 3,5-bis(hetero)aromatic

• are formed, they immediately react with hydrazine to form pyrazole by a specific rate acceleration in the one-pot process [16]. The Sonogashira cross-coupling of acid chlorides with terminal alkynes has also been demonstrated as a valuable tool to generate, in situ, ynones bearing a pendant amine

Combined directed ortho-zincation and palladium-catalyzed strategies: Synthesis of 4,n-dimethoxy-substituted benzo[b]furans

• Verónica Guilarte,
• M. Pilar Castroviejo,
• Estela Álvarez and
• Roberto Sanz

Beilstein J. Org. Chem. 2011, 7, 1255–1260, doi:10.3762/bjoc.7.146

• benzo[b]furan derivatives has been developed from 3-halo-2-iodoanisoles bearing an additional methoxy group, which have been accessed through an ortho-zincation/iodination reaction. Two palladium-catalyzed processes, namely a Sonogashira coupling followed by a tandem hydroxylation/cyclization sequence

• ring system, the cyclodehydration of α-aryloxy ketones [29], the Claisen rearrangement of an allyl aryl ether followed by Pd-catalyzed intramolecular oxidative cyclization [30], and the tandem Sonogashira coupling/heterocyclization of 2-halophenols with terminal alkynes [31], are some of the most used

• Sonogashira coupling and a tandem hydroxylation/heterocyclization reaction. The required o-dihaloanisole derivatives could be prepared by a selective ortho-metallation reaction and subsequent electrophilic quenching with iodine (Scheme 1). Results and Discussion As established in our proposed retrosynthetic

One-pot four-component synthesis of pyrimidyl and pyrazolyl substituted azulenes by glyoxylation–decarbonylative alkynylation–cyclocondensation sequences

• Charlotte F. Gers,
• Julia Rosellen,
• Eugen Merkul and
• Thomas J. J. Müller

Beilstein J. Org. Chem. 2011, 7, 1173–1181, doi:10.3762/bjoc.7.136

• one-pot four-component syntheses toward pyrimidyl- and pyrazolylazulenes. Results and Discussion Recently, we reported a three-component synthesis leading to the formation of ynones by a conceptually novel glyoxylation–decarbonylative Sonogashira coupling sequence (Scheme 2) [47]. The Lewis acid free

• glyoxylation of electron rich N-heterocycles, such as indoles and pyrroles, leads to the formation of glyoxylyl chlorides, which can be reacted without isolation by decarbonylative Sonogashira coupling to form the desired ynones. So far, only one example of the synthesis of azulenylynones has been described

• monitoring by TLC, glyoxylation of guaiazulene (1b) was incomplete even after 24 h reaction time (Table 1, entry 3). Shorter reaction times in the first step caused a substantial decrease of the yield (Table 1, entry 4), whereas longer reaction times in the Sonogashira coupling had no effect on the yield

Asymmetric Au-catalyzed cycloisomerization of 1,6-enynes: An entry to bicyclo[4.1.0]heptene

• Alexandre Pradal,
• Chung-Meng Chao,
• Patrick Y. Toullec and
• Véronique Michelet

Beilstein J. Org. Chem. 2011, 7, 1021–1029, doi:10.3762/bjoc.7.116

• studies. Synthesis of 1,6-enynes We prepared various oxygen-tethered 1,6-enynes according to classic methodologies employing a Williamson alkylation reaction and/or a Sonogashira cross-coupling [60][61] (Scheme 2 and Scheme 3). The known enyne 5 [62][63] was engaged in Pd-catalyzed coupling in the

• yield. We also envisaged preparing two trisubstituted alkenes 2g and 2h by an alkylation/Sonogashira sequence starting from commercially available substrates 7 and 8. We also selected some nitrogen-tethered 1,6-enynes 1b–e from the literature [23][41][42][43][44] and synthesized them to evaluate the

A practical two-step procedure for the preparation of enantiopure pyridines: Multicomponent reactions of alkoxyallenes, nitriles and carboxylic acids followed by a cyclocondensation reaction

• Christian Eidamshaus,
• Roopender Kumar,
• Mrinal K. Bera and
• Hans-Ulrich Reissig

Beilstein J. Org. Chem. 2011, 7, 962–975, doi:10.3762/bjoc.7.108

• nonaflates are excellent coupling partners in palladium-catalyzed transformations such as Suzuki, Stille, Heck and Sonogashira reactions [45]. However, in contrast to the smooth nonaflation, the selective O-alkylation of the synthesized pyridines turned out to be more challenging (Scheme 5). Whereas pyridone

Recent advances in the gold-catalyzed additions to C–C multiple bonds

• He Huang,
• Yu Zhou and
• Hong Liu

Beilstein J. Org. Chem. 2011, 7, 897–936, doi:10.3762/bjoc.7.103

• carbon–carbon bond coupling reactions have been less explored [88][89]. In 2008, Li et al. reported a gold(I) iodide catalyzed Sonogashira reaction [88]. Terminal alkynes 197 reacted smoothly with aryl iodides and bromides 198 in the presence of 1 mol % AuI and 1 mol % dppf to generate the corresponding

Isotopic labelling studies for a gold-catalysed skeletal rearrangement of alkynyl aziridines

• Paul W. Davies,
• Nicolas Martin and
• Neil Spencer

Beilstein J. Org. Chem. 2011, 7, 839–846, doi:10.3762/bjoc.7.96

• stabilising B. The substrates were prepared by Sonogashira reaction between propargyl alcohol and the appropriately substituted iodobenzene substrate 22, 23 (Scheme 12). Functional group interconversion of the alcohols by bromination and substitution results in the sulfonium salts 28, 29 which were reacted

Fine-tuning alkyne cycloadditions: Insights into photochemistry responsible for the double-strand DNA cleavage via structural perturbations in diaryl alkyne conjugates

• Wang-Yong Yang,
• Samantha A. Marrone,
• Nalisha Minors,
• Diego A. R. Zorio and
• Igor V. Alabugin

Beilstein J. Org. Chem. 2011, 7, 813–823, doi:10.3762/bjoc.7.93

• corresponding lysine conjugates shown in Figure 4. Results and Discussion Synthesis The regioisomeric diaryl alkynes were synthesized following the synthetic strategy previously outlined by us for compound 1 [25]. The Sonogashira coupling of the corresponding iodonitrobenzene with trimethylsilyl (TMS) acetylene

Au(I)/Au(III)-catalyzed Sonogashira-type reactions of functionalized terminal alkynes with arylboronic acids under mild conditions

• Deyun Qian and
• Junliang Zhang

Beilstein J. Org. Chem. 2011, 7, 808–812, doi:10.3762/bjoc.7.92

• , Chinese Academy of Sciences, Ling Ling Road 345 Shanghai 200032 (P. R. China) 10.3762/bjoc.7.92 Abstract A straightforward, efficient, and reliable redox catalyst system for the Au(I)/Au(III)-catalyzed Sonogashira cross-coupling reaction of functionalized terminal alkynes with arylboronic acids under

• mild conditions has been developed. Keywords: arylboronic acid; gold-catalysis; Sonogashira cross-coupling; Introduction The Sonogashira reaction has become the most important and widely used method for the synthesis of arylalkynes and conjugated enynes, which are precursors for natural products

• , pharmaceuticals and other materials [1][2][3]. In the past decade, considerable efforts have been made to enhance the efficiency and generality of this reaction. All kinds of palladium catalyst systems [4][5][6][7][8][9][10] and other metal catalyst systems [3] have been developed for facilitating the Sonogashira

One-pot gold-catalyzed synthesis of 3-silylethynyl indoles from unprotected o-alkynylanilines

• Jonathan P. Brand,
• Clara Chevalley and
• Jérôme Waser

Beilstein J. Org. Chem. 2011, 7, 565–569, doi:10.3762/bjoc.7.65

• access to 3-silylalkynyl indoles. To the best of our knowledge, this is the first example of a one-pot process combining a Au(III) and a Au(I) catalyst. Findings 2-Alkynylanilines 2 can be efficiently prepared from 2-iodoanilines 4 and terminal alkynes via Sonogashira reaction with Et3N as solvent

Synthesis of 5-(2-methoxy-1-naphthyl)- and 5-[2-(methoxymethyl)-1-naphthyl]-11H-benzo[b]fluorene as 2,2'-disubstituted 1,1'-binaphthyls via benzannulated enyne–allenes

• Yu-Hsuan Wang,
• Joshua F. Bailey,
• Jeffrey L. Petersen and
• Kung K. Wang

Beilstein J. Org. Chem. 2011, 7, 496–502, doi:10.3762/bjoc.7.58

• -naphthyl derivatives. Construction of a new 1-naphthyl ring as an essential step toward 1,1'-binaphthyls is rare [17][18][19]. Results and Discussion The Sonogashira reaction between 1-ethynyl-2-methoxybenzene (4a) and 1-iodo-2-[2-(trimethylsilyl)ethynyl]benzene produced 5a, which was desilylated to give

A rapid and efficient synthetic route to terminal arylacetylenes by tetrabutylammonium hydroxide- and methanol-catalyzed cleavage of 4-aryl-2-methyl-3-butyn-2-ols

• Jie Li and
• Pengcheng Huang

Beilstein J. Org. Chem. 2011, 7, 426–431, doi:10.3762/bjoc.7.55

• have been widely used in the preparation of photoelectric devices such as organic light-emitting diodes (OLEDs) [1][2][3][4], field-effect transistors (OFETs) [5][6], and organic photovoltaic cells (OPVCs) [7][8][9]. The palladium-catalyzed Sonogashira cross-coupling of an aryl halide with a mono

C–C (alkynylation) vs C–O (ether) bond formation under Pd/C–Cu catalysis: synthesis and pharmacological evaluation of 4-alkynylthieno[2,3-d]pyrimidines

• Dhilli Rao Gorja,
• K. Shiva Kumar,
• K. Mukkanti and
• Manojit Pal

Beilstein J. Org. Chem. 2011, 7, 338–345, doi:10.3762/bjoc.7.44

• ]pyrimidines C (Figure 1). These derivatives are attractive due to the synthetic potential of C-4 alkynyl fragments for further use in library construction. A number of methods have been reported for the synthesis of alkynyl substituted pyrimidines and most of which involve the use of Sonogashira coupling of

• halopyrimidines with terminal alkynes [1][2][3] (for a review see [8]). While alkynylation of the thiophene ring of thienopyrimidines under Sonogashira conditions [9] has previously been reported [6], a similar coupling reaction on the pyrimidine ring of thieno[2,3-d]pyrimidines is uncommon in the literature [10

• ]. The use of Pd/C–CuI–PPh3 as a less expensive catalyst system for efficient Sonogashira coupling has been explored earlier. Due to our continuing interest in Pd/C-mediated alkynylation of aryl and heteroaryl halides we decided to investigate the Pd/C-based methodology for the synthesis of our target

First synthesis of 2-(benzofuran-2-yl)-6,7-methylene dioxyquinoline-3-carboxylic acid derivatives

• Wentao Gao,
• Jia Liu,
• Yun Jiang and
• Yang Li

Beilstein J. Org. Chem. 2011, 7, 210–217, doi:10.3762/bjoc.7.28

• construction of the benzofuran moiety from intermediate 5. For the construction of 2-substituted benzofurans, the most widely used approach involves the palladium-catalyzed heteroannulation of 2-halophenols with a terminal alkyne via a tandem Sonogashira coupling-5-endo-dig-cyclization, largely based on the

Donor-acceptor substituted phenylethynyltriphenylenes – excited state intramolecular charge transfer, solvatochromic absorption and fluorescence emission

• Ritesh Nandy and
• Sethuraman Sankararaman

Beilstein J. Org. Chem. 2010, 6, 992–1001, doi:10.3762/bjoc.6.112

• (2) with 1,1-dimethylpropargyl alcohol followed by deprotection with KOH in refluxing toluene (Scheme 2). 2-Phenylethynyltriphenylene (1a) and those bearing electron withdrawing substituent (1b–e) were synthesized by the Sonogashira coupling of 2-iodotriphenylene (2) with the corresponding

• phenylacetylene derivatives. Although 1f–g were also synthesized by this procedure, their purification proved difficult due to an inseparable minor product formed in these reactions. Therefore compounds 1f–g were synthesized via the Sonogashira coupling of 2-ethynyltriphenylene (4) and the corresponding

Conjugated polymers containing diketopyrrolopyrrole units in the main chain

• Bernd Tieke,
• A. Raman Rabindranath,
• Kai Zhang and
• Yu Zhu

Beilstein J. Org. Chem. 2010, 6, 830–845, doi:10.3762/bjoc.6.92

• polycondensation reactions such as Suzuki [17], Stille [18] and Heck [19] coupling are especially useful. Other suitable reactions are Ni-mediated Yamamoto coupling [20], Sonogashira coupling [21], or electrochemical polymerization [22]. In the following, a brief review of recently prepared DPP based polymers is

• -sensitized solar cells were fabricated with P-12 as active layer. A power conversion efficiency of 1.43% was reached. G. Zhang et al. [52] synthesized diphenylDPP-containing polyphenylene-vinylene (PPV)- and polyphenylene-ethynylene (PPE)-type conjugated polymers via Heck- and Sonogashira coupling

• Suzuki coupling and their characteristic properties. List of DPP-polymers prepared upon Stille, Heck and Sonogashira coupling and their characteristic properties. List of DPP-based polyiminoarylenes and their characteristic properties [37]. List of DPP-polymers prepared upon electrochemical

One-pot three-component synthesis of quinoxaline and phenazine ring systems using Fischer carbene complexes

• Priyabrata Roy and
• Binay Krishna Ghorai

Beilstein J. Org. Chem. 2010, 6, No. 52, doi:10.3762/bjoc.6.52

• ] using palladium catalyzed Sonogashira coupling reactions as depicted in Scheme 2. Iodoketone 6A was prepared in 80% yield from (3-chloro-2-pyrazinyl)phenylmethanone [35] by halogen exchange with NaI in acetonitrile. The three component coupling reaction of pyrazinyl ketone 1A, carbene complex 2 and N

Preparation of pyridine-3,4-diols, their crystal packing and their use as precursors for palladium-catalyzed cross-coupling reactions

• Tilman Lechel,
• Irene Brüdgam and
• Hans-Ulrich Reissig

Beilstein J. Org. Chem. 2010, 6, No. 42, doi:10.3762/bjoc.6.42

• possible palladium-catalyzed cross-couplings we performed several Sonogashira-reactions [28][29][30]. As described in Scheme 3, the pyridinyl-bistriflates or -nonaflates 3 were coupled with alkynes like phenylacetylene or (triisopropylsilyl)acetylene using Pd(PPh3)4 or alternatively, Pd(OAc)2/PPh3 as

• (C-H), 1600–1575 (C=C) cm−1. C12H10F9NO6S2 (499.3): calcd. C, 28.86; H, 2.02; N, 2.81; found: C, 28.89; H, 1.68; N 2.87. Sonogashira coupling reaction, typical procedure A mixture of pyridinediyl bistriflate 3b (245 mg, 0.491 mmol), Pd(PPh3)4 (79 mg, 0.069 mmol), CuI (9.4 mg, 0.049 mmol

• of 3-alkoxypyridinols 1 to pyridine-3,4-diols 2. aMethod a: Pd/C, H2, MeOH, rt, 1 d; bMethod b: BBr3, CH2Cl2, 0 °C to rt, 1 d; cMethod c: TFA:CH2Cl2 (1:2), rt, 1 h. Conversion of pyridine-3,4-diols 2 into pyridinediyl bistriflates or -nonaflates 3. a) Et3N, Rf2O, CH2Cl2, 0 °C to rt, 1 d. Sonogashira