Study on the synthesis of the cyclopenta[f]indole core of raputindole A

• Nils Marsch,
• Mario Kock and
• Thomas Lindel

Beilstein J. Org. Chem. 2016, 12, 334–342, doi:10.3762/bjoc.12.36

• included the second indole moiety of raputindole A (1). Boc protection of 6-iodoindole (2) [35], Sonogashira reaction of 3 with TMS-acetylene, and desilylation gave the N-protected alkynylindole 4 in excellent yield (Scheme 2). Boc-iodoindole 3 was also the precursor of the coupling partner, ketone 6

Hydroquinone–pyrrole dyads with varied linkers

• Hao Huang,
• Christoffer Karlsson,
• Maria Strømme,
• Martin Sjödin and
• Adolf Gogoll

Beilstein J. Org. Chem. 2016, 12, 89–96, doi:10.3762/bjoc.12.10

• microwave heating [22], allowing the reaction to be completed in half an hour with 95% yield. A second Sonogashira reaction of 10 with 3-iodo-1-(triisopropylsilyl)-1H-pyrrole afforded the protected pyrrole derivative 4d. For this second Sonogashira reaction, these conditions, when attempting to couple 10 to

Cross-metathesis reaction of α- and β-vinyl C-glycosides with alkenes

• Ivan Šnajdr,
• Kamil Parkan,
• Filip Hessler and
• Martin Kotora

Beilstein J. Org. Chem. 2015, 11, 1392–1397, doi:10.3762/bjoc.11.150

• ][4][5][6][7][8][9][10][11][12][13]. Thus the ethyne moiety was used in [2 + 2 + 2] cyclotrimerization to yield aryl C-deoxyribosides [3] and in a Sonogashira reaction for the synthesis of butenolidyl C-deoxyribosides [4]. Substituted alkynyl C-deoxyribosides [5][10][11] were used in other types of

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

• followed by deoxygenation which finally gave the paracyclophane 108 (85%, Scheme 15). Pinacol coupling: Kanomata and co-workers [123] have reported the synthesis of the cyclophane 112 by using pinacol coupling [124] mediated by SmI2. A double Sonogashira reaction of 1,4-diiodobenzene (109) with 4-pentyn-1

• –c with (3-cyanopropyl)dimethylsilyl chloride (CPDMSCl) (118). This protecting group was chosen to facilitate the separation of the mono- and diprotected products generated in this reaction. The two building blocks 116 and 119a–c were subsequently assembled via the Sonogashira reaction producing

Single-molecule conductance of a chemically modified, π-extended tetrathiafulvalene and its charge-transfer complex with F₄TCNQ

• Raúl García,
• M. Ángeles Herranz,
• Edmund Leary,
• M. Teresa González,
• Gabino Rubio Bollinger,
• Marius Bürkle,
• Linda A. Zotti,
• Yoshihiro Asai,
• Fabian Pauly,
• Juan Carlos Cuevas,
• Nicolás Agraït and
• Nazario Martín

Beilstein J. Org. Chem. 2015, 11, 1068–1078, doi:10.3762/bjoc.11.120

• groups in 3 is carried out through a second Sonogashira reaction. The coupling of 2,6-diethynyl-exTTF 3 with 1-acetylthio-4-iodobenzene (4), in the presence of Pd(II) and copper iodide and DIPEA in THF, led to the target molecule 5 in moderate yield (35%). Compound 4 was obtained in one step and with

Self-assembly of heteroleptic dinuclear metallosupramolecular kites from multivalent ligands via social self-sorting

• Christian Benkhäuser and
• Arne Lützen

Beilstein J. Org. Chem. 2015, 11, 693–700, doi:10.3762/bjoc.11.79

• commercially available 2-aminopyridine (4) (Scheme 4) following mostly literature-known protocols. The electrophilic iodination of aminopyridine 4 gave iodide 5 in good yield. Compound 5 was then subjected to a Sandmeyer-like chlorination to 6 which in turn was transformed in a Sonogashira reaction with

• alkyne 11 in 96% yield [28]. Finally, a two-fold Sonogashira reaction with 1,3-diiodobenzene afforded the desired bis(2,2’-bipyridine) ligand 2 in quantitative yield. Metal coordination After the successful synthesis we prepared a DMSO solution of copper(I) ions, added it to the ligands (rac)-1 and 2

Synthesis and chemosensing properties of cinnoline-containing poly(arylene ethynylene)s

• Natalia A. Danilkina,
• Petr S. Vlasov,
• Semen M. Vodianik,
• Andrey A. Kruchinin,
• Yuri G. Vlasov and
• Irina A. Balova

Beilstein J. Org. Chem. 2015, 11, 373–384, doi:10.3762/bjoc.11.43

• [57]. The ADIMET approach usually gives products with higher molecular weights and fewer defects than the Pd-catalyzed polycondensation by the Sonogashira reaction. On the other hand, the Sonogashira coupling is more tolerant to different functional groups and allows the polymer structure to be varied

Synthesis of trifluoromethyl-substituted pyrazolo[4,3-c]pyridines – sequential versus multicomponent reaction approach

• Barbara Palka,
• Angela Di Capua,
• Maurizio Anzini,
• Gyté Vilkauskaité,
• Algirdas Šačkus and
• Wolfgang Holzer

Beilstein J. Org. Chem. 2014, 10, 1759–1764, doi:10.3762/bjoc.10.183

• in 5-chloropyrazole-4-aldehydes is sufficiently activated to act as the leaving group in such kind of C–C linkages [17]. Indeed, reaction of chloroaldehyde 2 with different alkynes 3a–c under typical Sonogashira reaction conditions afforded the corresponding cross-coupling products 4a–c in good

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

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

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

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

• 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

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

• preparation of internal alkynes [24]. We started our investigations with the persilylated 1-iodoglucal 7, which is easily available by a sequence of lithiation and iodination from the parent, fully TIPS-protected congener [25]. The Sonogashira reaction was carried out under standard conditions. Pd(PPh3)2Cl2

• in a twofold Sonogashira reaction with an excess of phenylacetylene resulted in a chemoselective monoalkynylation of the pseudoanomeric position in quantitative yield (Scheme 2). Even the use of an elevated temperature did not lead to the formation of an enediyne. Further refunctionalization of the

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

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

• order to suppress the concurrent formation of 2-substituted indoles 60 by direct cyclization of o-alkynylaniline intermediates under the classical Sonogashira reaction conditions. Interestingly, aryl bromides were used as a third partner and may be added at the beginning of this one-pot reaction since

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

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

• 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

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

Palladium- catalyzed cross coupling reactions of 4-bromo- 6H-1,2-oxazines

• Reinhold Zimmer,
• Elmar Schmidt,
• Michal Andrä,
• Marcel-Antoine Duhs,
• Igor Linder and
• Hans-Ulrich Reissig

Beilstein J. Org. Chem. 2009, 5, No. 44, doi:10.3762/bjoc.5.44

• the expected product 9d and a byproduct bearing a 4-enyne moiety at 4-position. This indicates an addition of a second alkyne molecule to the primary product 9. Similar results were observed for the Sonogashira reaction of 2a with propargylic alcohol [33]. After successful simple cross couplings of

• mono-halogenated 2, the 4,5-dibromo-3-phenyl-6H-1,2-oxazine 3a seemed to be an attractive candidate for a twofold Sonogashira reaction (Scheme 5). Treatment of 3a with an excess of phenylacetylene under conditions as described in Scheme 4 provided 5-bromo-4-alkynyl-substituted 6H-1,2-oxazine 10a as

Synthesis of novel photochromic pyrans via palladium- mediated reactions

• Christoph Böttcher,
• Gehad Zeyat,
• Saleh A. Ahmed,
• Elisabeth Irran,
• Thorben Cordes,
• Cord Elsner,
• Wolfgang Zinth and
• Karola Rueck-Braun

Beilstein J. Org. Chem. 2009, 5, No. 25, doi:10.3762/bjoc.5.25

• the presence of an Fmoc protecting group for the direct synthesis of ω-amino acid 6. Also, a Sonogashira reaction was conducted towards the synthesis of naphthopyran precursor 4, which is suitable for attachment to tripodal linker systems for the immobilization on surfaces [26]. Results and Discussion

Convenient methods for preparing π-conjugated linkers as building blocks for modular chemistry

• Jiří Kulhánek,
• Filip Bureš and
• Miroslav Ludwig

Beilstein J. Org. Chem. 2009, 5, No. 11, doi:10.3762/bjoc.5.11

• use as building blocks in Suzuki–Miyaura or Sonogashira coupling reactions. Keywords: boronic acid; donor/acceptor; linker; Sonogashira reaction; property tuning; push-pull; Suzuki–Miyaura reaction; Introduction Development of new organic compounds with improved and advanced properties is one of the

• % yield). Since the Sonogashira reaction between bromo derivatives and trimethylsilylacetylene proved to be sluggish and low yielding (even with a large excess of acetylene and elevated temperature), the bromo derivatives were converted to the corresponding iodo derivatives by lithiation and quenched with

• iodine (see Supporting Information File 1). Thus the Sonogashira reaction on iodo derivatives smoothly furnished TMS-protected acetylenes 10–12 in high yields and reaction times of about 30 min while the subsequent TMS group removal using TBAF (tetrabutylammonium fluoride) afforded desired π-linkers 7c

Recent progress on the total synthesis of acetogenins from Annonaceae

• Nianguang Li,
• Zhihao Shi,
• Yuping Tang,
• Jianwei Chen and
• Xiang Li

Beilstein J. Org. Chem. 2008, 4, No. 48, doi:10.3762/bjoc.4.48

Facile synthesis of two diastereomeric indolizidines corresponding to the postulated structure of alkaloid 5,9E- 259B from a Bufonid toad (Melanophryniscus)

• Angela Nelson,
• H. Martin Garraffo,
• Thomas F. Spande,
• John W. Daly and
• Paul J. Stevenson

Beilstein J. Org. Chem. 2008, 4, No. 6, doi:10.1186/1860-5397-4-6

• -vinyl iodide with a selectivity of 97:3. Finally, Sonogashira reaction [50] of the vinyl iodide with trimethylsilylacetylene followed by removal of the trimethylsilyl group gave synthetic 7. At this stage the C8 diastereoisomers were separated by flash chromatography, though the minor component was

• contaminated with triphenyl phosphine / phosphine oxide residue from the Sonogashira reaction. The two synthetic C8 diastereoisomers were compared to natural 5,9E-259B present in the alkaloid fraction obtained from a bufonid toad, Melanophryniscus stelzneri [51]. The GC mass spectra of the three compounds were