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

• Sonogashira coupling reaction (Scheme 3). Thus, 2,5-dimethoxyphenyl bromide (8) was converted to ((2,5-dimethoxyphenyl)ethynyl)trimethylsilane (9), which was desilylated by addition of NaOH (aq) to give 2-ethynyl-1,4-dimethoxybenzene (10). Sonogashira conditions were as described by Erdélyi et al. using

• 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

N-Methylphthalimide-substituted benzimidazolium salts and PEPPSI Pd–NHC complexes: synthesis, characterization and catalytic activity in carbon–carbon bond-forming reactions

• Senem Akkoç,
• Yetkin Gök,
• İlhan Özer İlhan and
• Veysel Kayser

Beilstein J. Org. Chem. 2016, 12, 81–88, doi:10.3762/bjoc.12.9

• complexes have been used in different coupling reactions such as Mizoroki–Heck cross-coupling [22][23], Suzuki–Miyaura cross-coupling [24][25], Sonogashira [26] and arylation reactions [27]. There are suitable precatalyst scaffolds, which were developed by Nolan [28], Organ [21] and Buchwald [29]. To find

Solving the puzzling competition of the thermal C²–C⁶ vs Myers–Saito cyclization of enyne-carbodiimides

• Anup Rana,
• Mehmet Emin Cinar,
• Debabrata Samanta and
• Michael Schmittel

Beilstein J. Org. Chem. 2016, 12, 43–49, doi:10.3762/bjoc.12.6

• in the Myers–Saito pathway. The synthetic strategy (Scheme 3) was to first prepare carbodiimide 10 [24] according to a literature procedure. In the next step, a Sonogashira coupling between 10 and N,N-dimethylprop-2-yn-1-amine afforded the desired enyne-carbodiimide 11 in 24% yield. Thermolysis of 11

Asymmetric 1,4-bis(ethynyl)bicyclo[2.2.2]octane rotators via monocarbinol functionalization. Ready access to polyrotors

• Cyprien Lemouchi and
• Patrick Batail

Beilstein J. Org. Chem. 2015, 11, 1881–1885, doi:10.3762/bjoc.11.202

• variety of functionalization sequences of BCO rotators by performing nucleophilic reactions on the terminal alkyne [16] as well as Sonogashira coupling reactions [17]. One way to synthesize 1 is via a catalytic reaction to achieve the deprotection of a single 2-methyl-3-butyn-2-ol and transform the

• or 8 by Sonogashira coupling reactions (Scheme 4). Route 1 was preferred on account of higher yields. The ester function is necessary to purify the intermediate 13 and isolate 14 with excellent purity. These results demonstrate the viability of our approach of the desymmetrization of 1,4-bis(ethynyl

Polythiophene and oligothiophene systems modified by TTF electroactive units for organic electronics

• Alexander L. Kanibolotsky,
• Neil J. Findlay and
• Peter J. Skabara

Beilstein J. Org. Chem. 2015, 11, 1749–1766, doi:10.3762/bjoc.11.191

• polymer 1d, which was obtained by Sonogashira coupling of 1b with 1e and exhibited a partial solubility in THF with Mw = 610000 Da (THF soluble fraction) [43] (Scheme 1). Polymer properties in the solid state are hugely important for organic electronics applications, with the electronic properties of

SmI₂-mediated dimerization of indolylbutenones and synthesis of the myxobacterial natural product indiacen B

• Nils Marsch,
• Peter G. Jones and
• Thomas Lindel

Beilstein J. Org. Chem. 2015, 11, 1700–1706, doi:10.3762/bjoc.11.184

• -configuration were formed by SmI2-mediated reductive dimerization of a 4-(indol-6-yl)butenone, obtained by Heck reaction. The two indolyl units appear to chelate Sm(II)/(III) leading to a gauche-type arrangement at the newly formed bond between the two β-carbons. Through a sequence of Sonogashira cross coupling

• Nicolaou and Procter [31][32]. The pattern of geometrical [3 + 2] cycloaddition was also obtained with inverted enone moieties. 6-Prenoylindole (14) was synthesized in two steps from 6-iodoindole (4) by Sonogashira coupling with propargylic alcohol 12 and subsequent Meyer–Schuster rearrangement [33

Star-shaped tetrathiafulvalene oligomers towards the construction of conducting supramolecular assembly

• Masahiko Iyoda and
• Masashi Hasegawa

Beilstein J. Org. Chem. 2015, 11, 1596–1613, doi:10.3762/bjoc.11.175

• in solution and in the solid state even in neutral state [18]. Compounds 22 and 23 were synthesized in good yields by Sonogashira coupling reaction of 1,3,5-triethynylbenzene with 20 and 1,3,5-triiodobenzene with 21, respectively (Scheme 1). X-ray analysis of 22 revealed the columnar structure, in

• )[12]annulenes 28 and 29 were pepared by Sonogashira coupling of 26 with 24 and 27 with 25 in 25 and 36% yields, respectively. For the synthesis of 30 and 31, cyclotrimerization of 24 and 25 with a stoichiometric amount of PdCl2(PPh3)2 and CuI in triethylamine–THF was employed to afford 30 and 31 in 32

• cyclic conjugation and the interaction of the two TTF units in the neutral and cationic states, TTF-fused annulenes 33 [69] and radiannulenes 34 and 35 [70] were synthesized using a Sonogashira coupling in moderate yields (Figure 9). The thermodynamic study on the self-aggregation of tris(TTF)annulenes

Synthesis and spectroscopic properties of β-triazoloporphyrin–xanthone dyads

• Dileep Kumar Singh and
• Mahendra Nath

Beilstein J. Org. Chem. 2015, 11, 1434–1440, doi:10.3762/bjoc.11.155

• -diethynylxanthen-9-one (11) was synthesized in three steps from 3,6-dihydroxyxanthen-9-one (8) as a starting material. The first step involved the reaction of xanthone (8) with triflic anhydride in CH2Cl2 containing pyridine at 0 °C to afford 3,6-di-OTf-xanthone [52] (9). Subsequent Sonogashira coupling with

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

• moderate yield. RCM of the diene derived from the dialdehyde 111 afforded the macrocyclic cyclophane 113 as a less strained product (Scheme 16). Sonogashira coupling: Wegner and co-workers [125] have reported the synthesis of cyclophanes 122a–c via Sonogoshira coupling [126] (Scheme 17). To this end, the

• –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

The synthesis of active pharmaceutical ingredients (APIs) using continuous flow chemistry

• Marcus Baumann and
• Ian R. Baxendale

Beilstein J. Org. Chem. 2015, 11, 1194–1219, doi:10.3762/bjoc.11.134

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

• calculations to understand its electrical transport properties. Results and Discussion Synthesis and characterization of molecular wire 5 The synthesis of the target molecule is shown in Scheme 1 and starts from the previously reported 2,6-diiodo-exTTF 1 [23]. Reaction of 1 under Sonogashira conditions (Pd(II

• 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

Chiroptical properties of 1,3-diphenylallene-anchored tetrathiafulvalene and its polymer synthesis

• Masashi Hasegawa,
• Junta Endo,
• Seiya Iwata,
• Toshiaki Shimasaki and
• Yasuhiro Mazaki

Beilstein J. Org. Chem. 2015, 11, 972–979, doi:10.3762/bjoc.11.109

• process as shown in Scheme 1. Thus, starting with 1-(4-bromophenyl)-2-methylpropanone (4), which was prepared from bromobenzaldehyde (see Supporting Information File 1), which upon treatment with lithium acetylide at low temperature gave racemic propargyl alcohol 5 in 94% yield. Sonogashira coupling

Interactions between tetrathiafulvalene units in dimeric structures – the influence of cyclic cores

• Huixin Jiang,
• Virginia Mazzanti,
• Christian R. Parker,
• Søren Lindbæk Broman,
• Jens Heide Wallberg,
• Karol Lušpai,
• Adam Brincko,
• Henrik G. Kjaergaard,
• Anders Kadziola,
• Peter Rapta,
• Ole Hammerich and
• Mogens Brøndsted Nielsen

Beilstein J. Org. Chem. 2015, 11, 930–948, doi:10.3762/bjoc.11.104

• conjugated buta-1,3-diynediyl bridge between the two TTFs. Results and Discussion Synthesis The synthesis of 4 and 5 was accomplished according to Scheme 1 starting from the known TTF-iodide 9, readily prepared from compound 3b [16]. A Sonogashira coupling with trimethylsilylacetylene gave 10 that after

• desilylation was either subjected to a Sonogashira coupling with 9 to give 4 or to an oxidative Hay coupling to give 5 – using recently developed conditions where 4 Å molecular sieves were added to the reaction mixture to remove water [17]. Compounds 6 and 7 were prepared by treating 9 with either the trans

• -TEE 11 [18] or 2,6-diethynylpyridine 12 in Sonogashira coupling reactions (Scheme 2). The unsymmetrical radiaannulene 8 was prepared according to Scheme 3. The TEE-TTF derivative 13 [15] was reacted in a Sonogashira coupling with an excess of trimethylsilylacetylene to furnish the product 14. Removal

Gold-catalyzed formation of pyrrolo- and indolo-oxazin-1-one derivatives: The key structure of some marine natural products

• Sultan Taskaya,
• Nurettin Menges and
• Metin Balci

Beilstein J. Org. Chem. 2015, 11, 897–905, doi:10.3762/bjoc.11.101

• and N-propargylindole-2-carboxylic acids 37, 41 and 45, which were synthesized by hydrolysis of the corresponding esters (Table 2). The Sonogashira cross-coupling reaction [56][57][58][59][60][61] was used for the synthesis of the desired starting materials 29 and 33. For the Sonogashira coupling

Discrete multiporphyrin pseudorotaxane assemblies from di- and tetravalent porphyrin building blocks

• Mirko Lohse,
• Larissa K. S. von Krbek,
• Sebastian Radunz,
• Suresh Moorthy,
• Christoph A. Schalley and
• Stefan Hecht

Beilstein J. Org. Chem. 2015, 11, 748–762, doi:10.3762/bjoc.11.85

• benzylamine yielding amine 10, which was subsequently Boc-protected, then reacted with trimethylsilylacetylene in a Sonogashira cross-coupling followed by desilylation. Finally, the porphyrin cores 1 and 2 were combined with axle precursor 8 in another two and four-fold Sonogashira cross-coupling reaction

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

Design, synthesis and photochemical properties of the first examples of iminosugar clusters based on fluorescent cores

• Mathieu L. Lepage,
• Antoine Mirloup,
• Manon Ripoll,
• Fabien Stauffert,
• Anne Bodlenner,
• Raymond Ziessel and
• Philippe Compain

Beilstein J. Org. Chem. 2015, 11, 659–667, doi:10.3762/bjoc.11.74

• function to yield the trimethylsilylacetylene derivatives 9 and 11 using standard Sonogashira–Hagihira cross-coupling reactions promoted by low valent palladium precursors [62]. Excellent yields were obtained for the trisubstituted derivatives (88 to 95%). Two diagnostic NMR signals of the poly(ethylene

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

• ethynylene)s comprising a cinnoline core were prepared in high yields via a three-step methodology. A Richter-type cyclization of 2-ethynyl- and 2-(buta-1,3-diynyl)aryltriazenes was used for cinnoline ring formation, followed by a Sonogashira coupling for the introduction of trimethylsilylethynyl moieties

• and a sila-Sonogashira coupling as the polycondensation technique. The fluorescence of the cinnoline-containing polymers in THF was highly sensitive to quenching by Pd2+ ions. Keywords: cinnolines; fluorescence quenching; Pd2+ detection; poly(arylene ethynylene)s; Sonogashira coupling; Introduction

• -dibromocinnolines 4a,b (Table 1). Triazenes 3a,b were synthesized from 4-bromo-2-iodophenyltriazene 1 by the Sonogashira coupling [44][45] with hexyne (2a) and TMS-protected diacetylene 2b using conditions for the one-pot TMS group removal and the Sonogashira coupling developed recently [46]. The last reaction

Anionic sigmatropic-electrocyclic-Chugaev cascades: accessing 12-aryl-5-(methylthiocarbonylthio)tetracenes and a related anthra[2,3-b]thiophene

• Laurence Burroughs,
• John Ritchie,
• Mkhethwa Ngwenya,
• Dilfaraz Khan,
• William Lewis and
• Simon Woodward

Beilstein J. Org. Chem. 2015, 11, 273–279, doi:10.3762/bjoc.11.31

• meso:rac 8a. We assign this transformation to an equilibrium between dialkoxide 9 and the benzylic anion 10. Intramolecular proton delivery via cyclic transition state 11 is proposed to favour the meso dialkoxide prior to protonic quench. Samples of rac enriched 8a were prepared from Sonogashira coupling

Scalable synthesis of 5,11-diethynylated indeno[1,2-b]fluorene-6,12-diones and exploration of their solid state packing

• Bradley D. Rose,
• Peter J. Santa Maria,
• Aaron G. Fix,
• Chris L. Vonnegut,
• Lev N. Zakharov,
• Sean R. Parkin and
• Michael M. Haley

Beilstein J. Org. Chem. 2014, 10, 2122–2130, doi:10.3762/bjoc.10.219

• dramatically alter the intermolecular electronic coupling, which is what ultimately dictates performance of the device [18][19]. Results and Discussion Synthesis. Our initial studies [20] toward 8 (Scheme 1) focused on the Sonogashira cross-coupling of known diiodo intermediate 9, which was prepared by double

• Kitamura gave tetrahalide 12 in good yield on >10 g scale [25]. Suzuki cross-coupling with 12 furnished p-terphenyl 14, followed by oxidation of the methyl groups to produce diacid 15. Intramolecular Friedel–Crafts acylation then afforded 5,11-dibromo-IF-dione 11. The yields for the Sonogashira cross

• . Black lines represent the molecules with circles denoting the centroid. Transannular cyclization route to diethynyl-IF-diones 8. Suzuki/Friedel-Crafts route to diethynyl-IF-diones 8. Diethynyl-IF-diones synthesized and yields for Sonogashira cross-coupling. Electrochemical and optical data for ID-diones

Building complex carbon skeletons with ethynyl[2.2]paracyclophanes

• Ina Dix,
• Lidija Bondarenko,
• Peter G. Jones,
• Thomas Oeser and
• Henning Hopf

Beilstein J. Org. Chem. 2014, 10, 2013–2020, doi:10.3762/bjoc.10.209

• Sonogashira coupling) [7]. For the smaller oligomers (dimers, trimers) the ortho-isomer with its opening angle of 60° between the ethynyl functions leads preferentially to (mono)cyclic hydrocarbons. For the meta-compound 3 we can expect both cyclic and acyclic (linear) products, and when the two ethynyl

• ] appears simple, we always obtained complex mixtures of products when 13 and excess 1,2-diiodobenzene (14) were subjected to Sonogashira coupling. The main product of this coupling process was the monoaldehyde 15 (i.e., the 1:1-coupling product of 13 and 14). The desired 2:1-product 16 was always isolated

• following pathway. Sonogashira coupling of iodide 15 with trimethylsilylacetylene furnished the TMS-protected aldehyde 23 in good yield. Deprotection and conversion of its formyl function into an ethynyl group by the Bestmann–Ohira protocol took place readily and provided the triacetylene 24, again in good

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

• is presented. Hence, microwave-assisted treatment of 5-chloro-1-phenyl-3-trifluoromethylpyrazole-4-carbaldehyde with various terminal alkynes in the presence of tert-butylamine under Sonogashira-type cross-coupling conditions affords the former title compounds in a one-pot multicomponent procedure

• all obtained products. Keywords: microwave-assisted reactions; multicomponent reactions; NMR (1H; 13C; 15N; 19F); Sonogashira coupling; trifluoromethylpyrazoles; Introduction Fluorine-containing compounds play an important role in medicinal and pharmaceutical chemistry as well as in agrochemistry [1

• pyrazole precursor. Employing the latter approach we recently presented a novel method for the synthesis of the pyrazolo[4,3-c]pyridine system by Sonogashira-type cross-coupling reaction of easily obtainable 5-chloro-1-phenyl-1H-pyrazole-4-carbaldehydes with various alkynes and subsequent ring-closure

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

• prepared p-bromophenyl-substituted bicyclic 1,2-oxazine derivatives 12, 13, 15 and 16 provide options to perform cross-coupling reactions such as Buchwald/Hartwig, Heck, Hiyama, Kumada, Sonogashira or Stille couplings. In order to examine the conditions for Suzuki cross-couplings we subjected bicyclic

Improving the reactivity of phenylacetylene macrocycles toward topochemical polymerization by side chains modification

• Simon Rondeau-Gagné,
• Jules Roméo Néabo,
• Maxime Daigle,
• Katy Cantin and
• Jean-François Morin

Beilstein J. Org. Chem. 2014, 10, 1613–1619, doi:10.3762/bjoc.10.167

• protection of the hydroxy moiety with TBS in order to facilitate the further synthetic steps by increasing the solubility of the compound (57% yield over 2 steps). Then, by using a standard Castro–Stephens–Sonogashira coupling, TMS protecting groups were installed (73% yield). After basic removal of the

• alkyne protective group, the half-macrocycle 5 was obtained by Castro–Stephens–Sonogashira coupling with previously reported 3,5-diiodooctylbenzene [39] in good yields despite of the possible polymerization side reaction (54% yield). TMS-protected alkynes were, then, installed on the half-macrocycle to

• approach was used for PAM3. Starting from previously synthesized compound 3, the half-macrocycle 9 was obtained by standard Castro–Stephens–Sonogashira coupling with dialkyne 8 in good yield (59%). It is noteworthy that compound 8 was obtained from oxidative deprotection of compound 7. After installing TMS