Synergistic approach to polycycles through Suzuki–Miyaura cross coupling and metathesis as key steps

• Sambasivarao Kotha,
• Milind Meshram and
• Chandravathi Chakkapalli

Beilstein J. Org. Chem. 2018, 14, 2468–2481, doi:10.3762/bjoc.14.223

• a CM in an efficient manner. Biaryl derivatives In view of the interesting properties of biaryl derivatives, we have identified a three-step sequence, which involve cross-enyne metathesis (CEM), DA reaction followed by SM coupling [46]. To this end, acetylene derivatives 96a,b were subjected to CEM

Efficient catalytic alkyne metathesis with a fluoroalkoxy-supported ditungsten(III) complex

• Henrike Ehrhorn,
• Janin Schlösser,
• Dirk Bockfeld and
• Matthias Tamm

Beilstein J. Org. Chem. 2018, 14, 2425–2434, doi:10.3762/bjoc.14.220

• ditungsten catalyst W2F3 was also employed in alkyne cross-metathesis (ACM), a reaction which is of large interest for the application of alkyne metathesis, but often leads to product mixtures. Therefore, (trimethylsilyl)propyne and (trimethylsilyl)acetylene were chosen as reaction partners in ACM, since

Synthesis of indolo[1,2-c]quinazolines from 2-alkynylaniline derivatives through Pd-catalyzed indole formation/cyclization with N,N-dimethylformamide dimethyl acetal

• Antonio Arcadi,
• Sandro Cacchi,
• Giancarlo Fabrizi,
• Francesca Ghirga,
• Antonella Goggiamani,
• Antonia Iazzetti and
• Fabio Marinelli

Beilstein J. Org. Chem. 2018, 14, 2411–2417, doi:10.3762/bjoc.14.218

• )acetylene (1) with aryl or vinyl halides and triflates followed by cyclization reactions (Scheme 1) [19]. The reaction, which tolerates a variety of important functional groups, likely involves the formation of the indole intermediates 2 (through aminopalladation/reductive elimination) [20][21] followed by

Synthesis of 9-arylalkynyl- and 9-aryl-substituted benzo[b]quinolizinium derivatives by Palladium-mediated cross-coupling reactions

• Siva Sankar Murthy Bandaru,
• Darinka Dzubiel,
• Heiko Ihmels,
• Mohebodin Karbasiyoun,
• Mohamed M. A. Mahmoud and
• Carola Schulzke

Beilstein J. Org. Chem. 2018, 14, 1871–1884, doi:10.3762/bjoc.14.161

• further purified. In the second approach, the copper acetylide was formed in situ by the reaction of the acetylene derivative with triethylamine in the presence of Cu+ salts. Hence, the reaction of iodobenzo[b]quinolizinium 5 with arylacetylenes 7b–d in the presence of one equivalent of triethylamine and

[3 + 2]-Cycloaddition reaction of sydnones with alkynes

• Veronika Hladíková,
• Jiří Váňa and
• Jiří Hanusek

Beilstein J. Org. Chem. 2018, 14, 1317–1348, doi:10.3762/bjoc.14.113

• -yn-1,4-diones) [13][17][38][39], diphenylacetylene [1][2][9][13][15][32] or even acetylene itself [1][2] have also been successfully reacted with sydnones. The most typical procedure involves heating both components in boiling hydrocarbon solvent (benzene, toluene or xylene) for several hours (up to

• corresponding rather to type II or even type I cycloadditions. The most reactive were electron-poor alkynes (acetylene(di)carboxylates, benzoyl phenylacetylene) while electron-rich alkynes (tetradec-1-yne, 1-phenylpropyne) were much less reactive. Unfortunately, the reaction rate constant was not measured for

• the reaction with acetylene itself. However, on the basis of the published [1][2] synthetic protocol (acetone, 170 °C, 25 h) it appears that this cycloaddition is very slow and requires a higher temperature. Recently [42][43][44], a kinetic investigation was performed for the cycloaddition of various

Photocatalytic formation of carbon–sulfur bonds

• Alexander Wimmer and
• Burkhard König

Beilstein J. Org. Chem. 2018, 14, 54–83, doi:10.3762/bjoc.14.4

• . Radical addition to the alkyne leads to the anti-Markovnikov adduct via the more stable secondary radical intermediate. As alkyne 2-methyl-3-butyn-2-ol was selected, which is easily prepared from acetylene and acetone on large scale and the respective thiol–yne adducts can be converted into valuable

• (Scheme 35) [70]. o-Methylthioaryl diazonium salts and phenylacetylene are starting materials, and photoexcited Eosin Y transfers an electron to the diazonium salt, which decomposes into a reactive aryl radical and N2. Addition to the acetylene yields a vinylic radical intermediate, which cyclizes to the

• combination of KOH/DMSO and 2-halothioanisole forms an orange adduct, which absorbs visible-light. They propose that KOH/DMSO as a superbase can photoreduce the aryl halide, which subsequently generates an aryl radical by expelling the halide anion. Radical addition to the acetylene derivative yields a vinyl

Recent applications of click chemistry for the functionalization of gold nanoparticles and their conversion to glyco-gold nanoparticles

• Vivek Poonthiyil,
• Thisbe K. Lindhorst,
• Vladimir B. Golovko and
• Antony J. Fairbanks

Beilstein J. Org. Chem. 2018, 14, 11–24, doi:10.3762/bjoc.14.2

• acetylene-functionalized Thermomyces lanuginosus lipase was then attached to these azide-functionalized water-soluble AuNPs by CuAAC (Scheme 7). It was found that the enzyme retained its activity after the click reaction. However, the vast excesses of both Cu (a one million-fold excess relative to the azide

• polymersomes and strained alkyne-functionalized AuNPs (DBCO-AuNPs) in water [57]. Functionalization of AuNPs with an azide containing thiol ligand, and subsequent attachment to an acetylene-functionalized lipase by CuAAC. Reagents and conditions: (a) H2O, rt, 18 h; (b) H2O, CuSO4, ascorbic acid, rt, 3 d. [47

Structure–property relationships and third-order nonlinearities in diketopyrrolopyrrole based D–π–A–π–D molecules

• Jan Podlesný,
• Lenka Dokládalová,
• Oldřich Pytela,
• Adam Urbanec,
• Milan Klikar,
• Numan Almonasy,
• Tomáš Mikysek,
• Jaroslav Jedryka,
• Iwan V. Kityk and
• Filip Bureš

Beilstein J. Org. Chem. 2017, 13, 2374–2384, doi:10.3762/bjoc.13.235

• distinguished (n = 0 or 1). Whereas chromophores in series a possess the donor directly connected to the DPP acceptor, in series b are these moieties separated by an additional acetylene unit. The reaction sequence leading to target chromophores 1–5 consists of a three-step preparation of dibromo derivative 8

• decompose far beyond their melting points (e.g., 2a with Tm = 244 °C and Td = 345 °C). Compounds in series b bearing an additional acetylene linker decompose almost immediately after their melting (e.g., 2b with Tm = 175 °C and Td = 189 °C). In pairs of chromophores, the substance without triple bond has an

• approximately 50 °C higher melting point (e.g., 1a/1b with Tm = 261/215 °C). Thus, the insertion of an acetylene linker decreases the melting point and causes thermal instability in the liquid phase. Derivatives 1a/2a containing a 1,4-phenylene linker showed the highest Tm and Td values of 261/244 and 330/345

Is the tungsten(IV) complex (NEt₄)₂[WO(mnt)₂] a functional analogue of acetylene hydratase?

• Matthias Schreyer and
• Lukas Hintermann

Beilstein J. Org. Chem. 2017, 13, 2332–2339, doi:10.3762/bjoc.13.230

• [W(O)(mnt)2] (1; mnt = maleonitriledithiolate) was proposed (Sarkar et al., J. Am. Chem. Soc. 1997, 119, 4315) to be a functional analogue of the active center of the enzyme acetylene hydratase from Pelobacter acetylenicus, which hydrates acetylene (ethyne; 2) to acetaldehyde (ethanal; 3). In the

• acetylene. A critical assessment of, and a possible explanation for the earlier reported results are offered. The title question is answered with "no". Keywords: acetylene hydratase; alkynes; catalytic hydration; enzyme models; tungsten complexes; Introduction In 1985, the enzyme acetylene hydratase

• (classification: hydro-lyases, EC 4.2.1) was isolated from the bacterium Pelobacter acetylenicus [1], which feeds anaerobically on acetylene as sole carbon source [2]. The enzyme is a tungsten iron–sulfur protein requiring a strongly reducing environment for converting acetylene (ethyne; 2) to acetaldehyde

Synthesis and application of trifluoroethoxy-substituted phthalocyanines and subphthalocyanines

• Satoru Mori and
• Norio Shibata

Beilstein J. Org. Chem. 2017, 13, 2273–2296, doi:10.3762/bjoc.13.224

• diacetylene linkers, via a butadiyne and via an aryldiacetylene moiety (Figure 2). Such binuclear phthalocyanines that are connected via a rigid acetylene linker synthesized by Glaser or Sonogashira reactions have attracted attention due to their interesting effects resulting from further expansion of

The chemistry and biology of mycolactones

• Matthias Gehringer and
• Karl-Heinz Altmann

Beilstein J. Org. Chem. 2017, 13, 1596–1660, doi:10.3762/bjoc.13.159

Direct catalytic arylation of heteroarenes with meso-bromophenyl-substituted porphyrins

• Alexei N. Kiselev,
• Olga K. Grigorova,
• Alexei D. Averin,
• Sergei A. Syrbu,
• Oskar I. Koifman and
• Irina P. Beletskaya

Beilstein J. Org. Chem. 2017, 13, 1524–1532, doi:10.3762/bjoc.13.152

• via acetylene bridge [9]. All these compounds were synthesized from the corresponding aldehydes already possessing an heteroaromatic moiety. The development of the catalytic approaches opened an easy access to 2-aryl-substituted benzothiazoles, benzoxazoles and benzimidazoles. Kumada–Tamao–Corriu [10

Synthesis of novel 13α-estrone derivatives by Sonogashira coupling as potential 17β-HSD1 inhibitors

• Ildikó Bacsa,
• Rebeka Jójárt,
• János Wölfling,
• Gyula Schneider,
• Bianka Edina Herman,
• Mihály Szécsi and
• Erzsébet Mernyák

Beilstein J. Org. Chem. 2017, 13, 1303–1309, doi:10.3762/bjoc.13.126

• phenylacetylene using Pd(OAc)2 and CuI as catalysts [21]. They did not investigate the influence of the nature of the substituent on the phenyl ring of the acetylene on the course of the reactions. They carried out the full saturation of the C≡C bond of the 2-phenethynyl estrone with palladium on charcoal

Aggregation behaviour of a single-chain, phenylene-modified bolalipid and its miscibility with classical phospholipids

• Simon Drescher,
• Vasil M. Garamus,
• Christopher J. Garvey,
• Annette Meister and
• Alfred Blume

Beilstein J. Org. Chem. 2017, 13, 995–1007, doi:10.3762/bjoc.13.99

• alkyl chain of the bolalipid in order to fill the void volume. Besides heteroatoms [29][30], acetylene [31] or diacetylene groups [32], or methyl branches [31][33], also phenyl- or biphenyl rings were inserted into the long alkyl chain [34][35][36][37]. The insertion of a phenylene group led to PC

Interactions between shape-persistent macromolecules as probed by AFM

• Johanna Blass,
• Jessica Brunke,
• Franziska Emmerich,
• Cédric Przybylski,
• Vasil M. Garamus,
• Artem Feoktystov,
• Roland Bennewitz,
• Gerhard Wenz and
• Marcel Albrecht

Beilstein J. Org. Chem. 2017, 13, 938–951, doi:10.3762/bjoc.13.95

• backbone. Compared to monomer 7, peak broadening and the disappearance of the 1H NMR signals of the acetylene protons at 4.54 and 4.36 ppm indicate the formation of polymer 8. The presence of the conjugated backbone was confirmed by UV–vis and fluorescence measurements in water. Compared to 7, a

Transition-metal-free one-pot synthesis of alkynyl selenides from terminal alkynes under aerobic and sustainable conditions

• Adrián A. Heredia and
• Alicia B. Peñéñory

Beilstein J. Org. Chem. 2017, 13, 910–918, doi:10.3762/bjoc.13.92

• ). First, we explored the reactivity of KSeCN (2), n-octyl bromide (3a) and acetylene 6a in DMF as solvent under different atmospheric conditions (Table 1, entries 1–3). Conducting the reaction under an inert atmosphere, compound 5a was obtained with a yield of 38%. A slightly higher performance was

Nucleophilic and electrophilic cyclization of N-alkyne-substituted pyrrole derivatives: Synthesis of pyrrolopyrazinone, pyrrolotriazinone, and pyrrolooxazinone moieties

• Işıl Yenice,
• Sinan Basceken and
• Metin Balci

Beilstein J. Org. Chem. 2017, 13, 825–834, doi:10.3762/bjoc.13.83

• 9. Substituted alkyne derivatives 10a and 10b were synthesized according to the literature. The Sonogashira coupling reaction [25] of aryl iodides with terminal acetylene is an effective approach towards the synthesis of substituted arylalkynes. The reaction of 1-iodo-4-methoxybenzene and 1-iodo-4

A practical and efficient approach to imidazo[1,2-a]pyridine-fused isoquinolines through the post-GBB transformation strategy

• Taofeng Shao,
• Zhiming Gong,
• Tianyi Su,
• Wei Hao and
• Chao Che

Beilstein J. Org. Chem. 2017, 13, 817–824, doi:10.3762/bjoc.13.82

• acetylene unit may then undergo a sequential 6-exo-dig cyclization/retro-ene reaction to form the desired imidazo[1,2-a]pyridine-fused isoquinoline 6a. The cyclization reaction could be realized with the aid of silver or gold catalysts [51][52]. With this idea in mind, we commenced our studies by

• -ethynylbenzaldehydes 2 and tert-butylisocyanide (3). Indeed, the acetylene group in the aldehyde component had no obvious steric effect on the efficiency of the GBB reaction affording the GBB product in good to excellent yields in most cases. On the other hand, the substituent ortho to the amino group in the amidine

Effect of the ortho-hydroxy group of salicylaldehyde in the A³ coupling reaction: A metal-catalyst-free synthesis of propargylamine

• Sujit Ghosh,
• Kinkar Biswas,
• Suchandra Bhattacharya,
• Pranab Ghosh and
• Basudeb Basu

Beilstein J. Org. Chem. 2017, 13, 552–557, doi:10.3762/bjoc.13.53

• acetylene, established as a general protocol, and is believed to be of interest for synthetic chemists from green chemistry. Keywords: A3 coupling; metal-catalyst-free; propargylamine; salicylaldehyde; terminal alkyne; Introduction Propargylamines are important synthetic intermediates for the preparation

• activate the terminal acetylene primarily, which then undergoes a nucleophilic addition to the iminium electrophile generated from the aldehyde and the amine. Among different transition metals, copper metal has been mostly explored as the catalyst to activate the terminal acetylene, though there is a

• this case, activation of the Csp–COOH occurs via decarboxylation followed by the coupling with an iminium electrophile to produce the propargylamine. Although the strategy is interesting, functionalized acetylene carboxylic acids are difficultly accessible and the reaction is less 'atom economic

Iodination of carbohydrate-derived 1,2-oxazines to enantiopure 5-iodo-3,6-dihydro-2H-1,2-oxazines and subsequent palladium-catalyzed cross-coupling reactions

• Michal Medvecký,
• Igor Linder,
• Luise Schefzig,
• Hans-Ulrich Reissig and
• Reinhold Zimmer

Beilstein J. Org. Chem. 2016, 12, 2898–2905, doi:10.3762/bjoc.12.289

• coupling. For this purpose, we selected (trimethylsilyl)acetylene as alkyne component. The Sonogashira couplings of 5-iodo-1,2-oxazines syn-4a and anti-4a were carried out under standard conditions using a catalytic system consisting of PdCl2(PPh3)2, CuI and triethylamine in toluene at room temperature to

Multicomponent synthesis of spiropyrrolidine analogues derived from vinylindole/indazole by a 1,3-dipolar cycloaddition reaction

• Manjunatha Narayanarao,
• Lokesh Koodlur,
• Vijayakumar G. Revanasiddappa,
• Subramanya Gopal and
• Susmita Kamila

Beilstein J. Org. Chem. 2016, 12, 2893–2897, doi:10.3762/bjoc.12.288

• stereospecific cyclic adducts. Keywords: L-proline; ninhydrin; sarcosine; spiropyrrolidine; 5-vinylindazole; 5-vinylindole; Introduction The [3 + 2] cycloaddition between azomethine ylides and olefins/acetylene as dipolarophiles is an important reaction to access a number of novel heterocyclic spiro scaffolds

Thiophene-forming one-pot synthesis of three thienyl-bridged oligophenothiazines and their electronic properties

• Dominik Urselmann,
• Konstantin Deilhof,
• Bernhard Mayer and
• Thomas J. J. Müller

Beilstein J. Org. Chem. 2016, 12, 2055–2064, doi:10.3762/bjoc.12.194

• , 0.08 mmol), CuI (15.0 mg, 0.08 mmol), PPh3 (21 mg, 0.08 mmol), (trimethylsilyl)acetylene (0.56 mL, 2.00 mmol), and piperidine (5.00 mL, 50.4 mmol) were added. The closed vessel under nitrogen was heated at 55 °C (oil bath) for 16 h. Next, TBAF·3H2O (631 mg, 2.00 mmol) was added and the vessel open to

Synthesis and characterization of fluorinated azadipyrromethene complexes as acceptors for organic photovoltaics

• Forrest S. Etheridge,
• Roshan J. Fernando,
• Sandra Pejić,
• Matthias Zeller and
• Geneviève Sauvé

Beilstein J. Org. Chem. 2016, 12, 1925–1938, doi:10.3762/bjoc.12.182

• ][33][34]. (4-Fluorophenylethynyl)tributyltin (for the synthesis of L3), and [4-(trifluoromethyl)phenyl](tributyltin)acetylene (for the synthesis of L4) were synthesized according to literature procedures with minor modifications and used without purification [35][36]. Methods 1H, 19F, and 13C NMR

• , 684.39. L4: [4-(Trifluoromethyl)phenyl](tributyltin)acetylene (0.686 g, 1.495 mmol) and ADPI2 (0.313 g, 0.445 mmol) was taken into a Schlenk flask (100 mL), which was evacuated and refilled with N2 three times. Distilled xylenes (50 mL) were added to the flask using a syringe and placed under slight

• vacuum. Then Pd(PPh3)4 (0.049g, 10 mmol %) was added inside a glove box. The mixture was heated at 125 °C for 48 h under N2. After 48 h, additional [4-(trifluoromethyl)phenyl](tributyltin)acetylene (0.686 g, 1.495 mmol) and Pd(PPh3)4 (0.049g, 10 mmol %) were added in one shot. The reaction mixture was

A flow reactor setup for photochemistry of biphasic gas/liquid reactions

• Josef Schachtner,
• Patrick Bayer and
• Axel Jacobi von Wangelin

Beilstein J. Org. Chem. 2016, 12, 1798–1811, doi:10.3762/bjoc.12.170

• , O3, H2, Cl2, acetylene, NOx, CO, CO2, etc.) but obviously bear several challenges with regard to a reproducible and precise control of the addition and mixing of the three phases: the liquid phase, containing organic substrates, the photo-active component (catalyst or sensitizer), the solvent, and

Discovery of an inhibitor of the production of the Pseudomonas aeruginosa virulence factor pyocyanin in wild-type cells

• Bernardas Morkunas,
• Balint Gal,
• Warren R. J. D. Galloway,
• James T. Hodgkinson,
• Brett M. Ibbeson,
• Yaw Sing Tan,
• Martin Welch and
• David R. Spring

Beilstein J. Org. Chem. 2016, 12, 1428–1433, doi:10.3762/bjoc.12.137

• intramolecular cyclisation of an analogous β-ketoamide in sulphuric acid [27], or pallidum catalysed intramolecular cyclisation of an acetylene derivative under acidic conditions [28]. The 4-alkylquinolin-2(1H)-one molecular scaffold of compound 4 is clearly distinct from that of AHLs; to the best of our