Preparation of trinucleotide phosphoramidites as synthons for the synthesis of gene libraries

• Ruth Suchsland,
• Bettina Appel and
• Sabine Müller

Beilstein J. Org. Chem. 2018, 14, 397–406, doi:10.3762/bjoc.14.28

• -azidomethylbenzoyl)-protected nucelosides, followed by removal of the 5'-O-DMTr group and extension of the dimer to the trimer by coupling of another N-acyl-3'-O-(o-chlorophenylphosphate)nucleoside. The final removal of the 2-azidomethylbenzoyl group occurred by reduction of the azide with triphenylphosphine in

Recent advances on organic blue thermally activated delayed fluorescence (TADF) emitters for organic light-emitting diodes (OLEDs)

• Thanh-Tuân Bui,
• Fabrice Goubard,
• Malika Ibrahim-Ouali,
• Didier Gigmes and
• Frédéric Dumur

Beilstein J. Org. Chem. 2018, 14, 282–308, doi:10.3762/bjoc.14.18

CF₃SO₂X (X = Na, Cl) as reagents for trifluoromethylation, trifluoromethylsulfenyl-, -sulfinyl- and -sulfonylation and chlorination. Part 2: Use of CF₃SO₂Cl

• Hélène Chachignon,
• Hélène Guyon and
• Dominique Cahard

Beilstein J. Org. Chem. 2017, 13, 2800–2818, doi:10.3762/bjoc.13.273

• -trifluoromethylated analogues in the presence of trimethylphosphine, with moderate to excellent yields (Scheme 33). The higher nucleophilicity of trimethylphosphine versus triphenylphosphine and the water solubility of trimethylphosphine oxide byproducts were essential elements in choosing the reducing agent. Both

• triphenylphosphine in acetonitrile at 60 °C [44]. The addition of catalytic amounts of sodium iodide, while not being essential for the production of the trifluoromethylsulfenylated substrates, permitted to slightly increase the yields (Scheme 35). For that matter, excellent yields were achieved indifferently of the

CF₃SO₂X (X = Na, Cl) as reagents for trifluoromethylation, trifluoromethylsulfenyl-, -sulfinyl- and -sulfonylation. Part 1: Use of CF₃SO₂Na

• Hélène Guyon,
• Hélène Chachignon and
• Dominique Cahard

Beilstein J. Org. Chem. 2017, 13, 2764–2799, doi:10.3762/bjoc.13.272

• published the same reaction under slightly different conditions [46]. They used a combination CF3SO2Na/TBHP in the presence of catalytic amounts of copper chloride and triphenylphosphine. Trisubstituted alkenes (R3 and R4 ≠ H) were employed as substrates and diastereoisomers were obtained. The tert-butoxyl

Vinylphosphonium and 2-aminovinylphosphonium salts – preparation and applications in organic synthesis

• Anna Kuźnik,
• Roman Mazurkiewicz and
• Beata Fryczkowska

Beilstein J. Org. Chem. 2017, 13, 2710–2738, doi:10.3762/bjoc.13.269

• Wehman (Scheme 4) [10]. Vinylphosphonium salts can also be prepared by alkylation of phosphines (usually triphenylphosphine) with allyl halide derivatives and isomerization of allylphosphonium salts 4 thus obtained under the influence of bases such as triethylamine or sodium carbonate (Scheme 5) [11][12

• ][13]. Vinyl halides are relatively less reactive alkylating agents. However, the use of readily available vinyl triflates 5 for the alkylation of triphenylphosphine in THF solution in the presence of a catalytic amount of (Ph3P)4Pd (1–3 mol %) gave the expected vinylphosphonium salts in a yield of 62

• triphenylphosphine with 1-bromoethylbenzene. The resulting phosphonium salt 11 was then deprotonated to the corresponding ylide 12, which in the last step was subjected to bromination to give the expected α-bromoethylphosphonium bromide 13 [10]. 1.3. Peterson olefination of α-trimethylsilylphosphonium ylides with

Phosphonic acid: preparation and applications

• Charlotte M. Sevrain,
• Mathieu Berchel,
• Hélène Couthon and
• Paul-Alain Jaffrès

Beilstein J. Org. Chem. 2017, 13, 2186–2213, doi:10.3762/bjoc.13.219

• with triphenylphosphine functionalized either by two or three phosphonic acid sodium salts; the former being more water soluble than the later [24]. This behavior is associated to the fact that the trisphosphonic acid sodium salt was already solvated at the solid state. The high polarity of the

Mechanochemical synthesis of small organic molecules

• Tapas Kumar Achar,
• Anima Bose and
• Prasenjit Mal

Beilstein J. Org. Chem. 2017, 13, 1907–1931, doi:10.3762/bjoc.13.186

• Reaction Pecharsky and co-workers reported the solvent-free mechanochemical synthesis of phosphonium salts [54] and phosphorus ylides [55] in the presence of the weak base K2CO3. Mechanochemically prepared phosphorous ylide from triphenylphosphine in presence of K2CO3 was utilized for a one-pot solvent

Pd(OAc)₂/Ph₃P-catalyzed dimerization of isoprene and synthesis of monoterpenic heterocycles

• Dominik Kellner,
• Maximilian Weger,
• Andrea Gini and
• Olga García Mancheño

Beilstein J. Org. Chem. 2017, 13, 1807–1815, doi:10.3762/bjoc.13.175

• procedure towards the tail-to-tail dimer using readily available Pd(OAc)2 and inexpensive triphenylphosphine as ligand. Furthermore, simple screw cap vials are employed, allowing carrying out the reaction at low pressure. In addition, the potential of the dimer as a chemical platform for the preparation of

• been developed. A high selectivity towards the tail-to-tail dimer was achieved by using readily available Pd(OAc)2 and inexpensive triphenylphosphine as ligand in the presence of catalytic amounts of Et3N as base. The reaction can be performed with common chemicals and solvents at low pressure in

1-Imidoalkylphosphonium salts with modulated C_α–P⁺ bond strength: synthesis and application as new active α-imidoalkylating agents

• Jakub Adamek,
• Roman Mazurkiewicz,
• Anna Węgrzyk and
• Karol Erfurt

Beilstein J. Org. Chem. 2017, 13, 1446–1455, doi:10.3762/bjoc.13.142

• succinimide-derived products 5 (A = (CH2)2) were generally lower. In the case of N-(1-methoxyethyl)-1,8-naphthalimide the triphenylphosphine attack on the α-carbon resulted in the splitting of the Cα–N bond instead of the Cα–OMe bond and the corresponding 1-methoxyethyltriphenylphosphonium tetrafluoroborate

Strategies toward protecting group-free glycosylation through selective activation of the anomeric center

• A. Michael Downey and
• Michal Hocek

Beilstein J. Org. Chem. 2017, 13, 1239–1279, doi:10.3762/bjoc.13.123

Glyco-gold nanoparticles: synthesis and applications

• Federica Compostella,
• Olimpia Pitirollo,
• Alessandro Silvestri and
• Laura Polito

Beilstein J. Org. Chem. 2017, 13, 1008–1021, doi:10.3762/bjoc.13.100

• metal-based anticancer drugs need to be developed. Recently, it has been reported the interesting synthesis of AuNPs coated with glyco-polymers and functionalized with gold(I) triphenylphosphine (Figure 7) [88]. This work showed the potentiality of these structures as novel cancer therapeutic drugs. The

Exploring endoperoxides as a new entry for the synthesis of branched azasugars

• Svenja Domeyer,
• Mark Bjerregaard,
• Henrik Johansson and
• Daniel Sejer Pedersen

Beilstein J. Org. Chem. 2017, 13, 644–647, doi:10.3762/bjoc.13.63

• was a Wittig reaction with methyltriphenylphosphonium iodide to provide 14–16. Compound 14 was found to be volatile and thus was only isolated in a poor yield. For diene 15 the low yield was largely due to complications with removing the triphenylphosphine oxide side product. However, at this stage

• anticipated that the reaction conditions could be optimised to favour the desired diol product. Ring contraction of acetonide-protected endoperoxide 23 by treatment with triphenylphosphine provided ready access to tetrahydrofuran 24 in good yield [21]. Finally, treatment of endoperoxide 23 with Co(salen) gave

Unpredictable cycloisomerization of 1,11-dien-6-ynes by a common cobalt catalyst

• Abdusalom A. Suleymanov,
• Dmitry V. Vasilyev,
• Valentin V. Novikov,
• Yulia V. Nelyubina and
• Dmitry S. Perekalin

Beilstein J. Org. Chem. 2017, 13, 639–643, doi:10.3762/bjoc.13.62

• (allyloxy)but-2-yne (1a) and 1,4-di(N-allyltosylamido)-2-butyne (1b) as test substrates for our investigation (Scheme 2). It was found that in the presence of CoBr2, Zn and ZnI2 (20 mol % each) as well as the triphenylphosphine ligand (40 mol %) in 1,2-dichloroethane (DCE) these substrates underwent clean

• derivative 2c in the presence of the triphenylphosphine ligand. More surprisingly, the same product was obtained when dppe or dppp were used as ligands, although the small amounts of isomeric by-products were detected in these cases. Noteworthy, according to the NMR spectra, product 2c was formed as a single

Brønsted acid-mediated cyclization–dehydrosulfonylation/reduction sequences: An easy access to pyrazinoisoquinolines and pyridopyrazines

• Ramana Sreenivasa Rao and
• Chinnasamy Ramaraj Ramanathan

Beilstein J. Org. Chem. 2017, 13, 428–440, doi:10.3762/bjoc.13.46

• reaction mixture was purified through silica gel column chromatography using ethyl acetate/hexane, 30:70 as eluent to afford 12a and 12b in the ratio 79:21. The regioisomers of bromopyrazinone (12a and 12b) (1.0 mmol), bis(triphenylphosphine)palladium(II) chloride (10 mol %, 7 mg) in dimethylformamide (2

Decarboxylative and dehydrative coupling of dienoic acids and pentadienyl alcohols to form 1,3,6,8-tetraenes

• Ghina’a I. Abu Deiab,
• Mohammed H. Al-Huniti,
• I. F. Dempsey Hyatt,
• Emma E. Nagy,
• Kristen E. Gettys,
• Sommayah S. Sayed,
• Christine M. Joliat,
• Paige E. Daniel,
• Rupa M. Vummalaneni,
• Andrew T. Morehead Jr,
• Andrew L. Sargent and
• Mitchell P. Croatt

Beilstein J. Org. Chem. 2017, 13, 384–392, doi:10.3762/bjoc.13.41

• greater amounts of triphenylphosphine lowering the reaction yield when using the Pd2dba3 catalyst (Table 1, entries 12–14). It was determined that reactions performed in the presence of electron-rich ligands had both quicker kinetics and more efficient yields compared to electron-deficient ligands (Table

Synthesis and optical properties of new 5'-aryl-substituted 2,5-bis(3-decyl-2,2'-bithiophen-5-yl)-1,3,4-oxadiazoles

• Anastasia S. Kostyuchenko,
• Tatyana Yu. Zheleznova,
• Anton J. Stasyuk,
• Aleksandra Kurowska,
• Wojciech Domagala,
• Adam Pron and
• Alexander S. Fisyuk

Beilstein J. Org. Chem. 2017, 13, 313–322, doi:10.3762/bjoc.13.34

• heating a mixture of ethyl 3-decyl-2,2'-bithiophene-5-carboxylate (7a) with aryl halides in the presence of tetrakis(triphenylphosphine)palladium(0) and AcOK in DMF for 20–22 h. Unfortunately, the yield of the phenyl-substituted product 7d remained low (18%), even when the reaction was performed for 55 h

Extrusion – back to the future: Using an established technique to reform automated chemical synthesis

• Deborah E. Crawford

Beilstein J. Org. Chem. 2017, 13, 65–75, doi:10.3762/bjoc.13.9

• well as the reaction between triphenylphosphine and nickel thiocyanate, both in the presence of stoichiometric amounts of MeOH (Figure 6) [2]. High-quality products were obtained, as determined by 1H NMR spectroscopy, PXRD analysis (which gave sharp diffraction patterns, indicating high crystallinity

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

• component in other Sonogashira couplings presented in former publications [23][32]. The reaction of syn-4a and alkyne 10 using palladium acetate, triphenylphosphine, and copper(I) iodide in a solvent mixture of diisopropylamine and DMF at room temperature gave the 5-(imidazolylethynyl)-substituted 1,2

Computational methods in drug discovery

• Sumudu P. Leelananda and
• Steffen Lindert

Beilstein J. Org. Chem. 2016, 12, 2694–2718, doi:10.3762/bjoc.12.267

• that by introducing a triphenylphosphine group into the base molecule pyridazinone, it is possible to obtain inhibitors for proteasome [2]. Further, analogs have been generated using this starting structure which showed high potency. Many studies show how CADD can influence the development of novel

From betaines to anionic N-heterocyclic carbenes. Borane, gold, rhodium, and nickel complexes starting from an imidazoliumphenolate and its carbene tautomer

• Ming Liu,
• Jan C. Namyslo,
• Martin Nieger,
• Mika Polamo and
• Andreas Schmidt

Beilstein J. Org. Chem. 2016, 12, 2673–2681, doi:10.3762/bjoc.12.264

• .12.264 Abstract The mesomeric betaine imidazolium-1-ylphenolate forms a borane adduct with tris(pentafluorophenyl)borane by coordination with the phenolate oxygen, whereas its NHC tautomer 1-(2-phenol)imidazol-2-ylidene reacts with (triphenylphosphine)gold(I) chloride to give the cationic NHC complex [Au

• on reaction with (triphenylphosphine)gold(I) chloride in boiling anhydrous THF under a nitrogen atmosphere, under which conditions the colorless gold complex [Au(6B)2][Cl] (9) is formed in 60% yield (Scheme 1). The protons of the OH resonate at δ = 10.34 ppm in DMSO-d6, and the 13C NMR chemical shift

• -cyclooctadiene)rhodium(I) dimer, or with bis(triphenylphosphine)rhodium(I) carbonyl chloride in anhydrous toluene at reflux temperature, respectively. During these reactions, the water of crystallization of the starting material is – at least partially – removed by azeotropic distillation and Rh(I) is obviously

New syntheses of (±)-tashiromine and (±)-epitashiromine via enaminone intermediates

• Darren L. Riley,
• Joseph P. Michael and
• Charles B. de Koning

Beilstein J. Org. Chem. 2016, 12, 2609–2613, doi:10.3762/bjoc.12.256

• planned reaction sequence was the alkylating cyclisation of the liberated alcohols 8a–c to produce the indolizidine nucleus (Scheme 2). The cyclisation was achieved by initially treating these deprotected enaminones with imidazole and triphenylphosphine at ambient temperature in acetonitrile followed by

• found that the bicyclic vinylogous urea 9d (64%) required a more careful flash chromatographic separation [19]. Unfortunately, the bicyclic vinylogous amide 9a could not be separated adequately from the triphenylphosphine residues under standard chromatographic and recrystallisation conditions. In an

• . We reverted to using the original procedure, but adjusted the purification protocol by first separating both the products and triphenylphosphine oxide residues from the baseline impurities by column chromatography, then removing most of the remaining triphenylphosphine residues by simple

Facile synthesis of a 3-deazaadenosine phosphoramidite for RNA solid-phase synthesis

• Elisabeth Mairhofer,
• Elisabeth Fuchs and
• Ronald Micura

Beilstein J. Org. Chem. 2016, 12, 2556–2562, doi:10.3762/bjoc.12.250

• catalysis at elevated pressure (30 psi) in ethanol or N,N-dimethylacetamide, ii) ammonium formiate, Pd/C, in methanol [28], iii) tin(II) chloride, in ethanol [29], iv) thioacetic acid, lutidine, in CH2Cl2 [30], v) triphenylphosphine, in CH2Cl2, aqueous work-up, and finally vi) Mg0 in methanol. Efficient 5

Efficient mechanochemical synthesis of regioselective persubstituted cyclodextrins

• Laszlo Jicsinszky,
• Marina Caporaso,
• Katia Martina,
• Emanuela Calcio Gaudino and
• Giancarlo Cravotto

Beilstein J. Org. Chem. 2016, 12, 2364–2371, doi:10.3762/bjoc.12.230

• to the known method [13], from freshly dried CDs on a 0.01 mol scale with triphenylphosphine and iodine in DMF. Per-6-bromo-γ-CD (2b’) was prepared in N-methylpyrrolidone by the same method using bromine. Per-6-chloro-β-CD (2a') was synthesized in a similar manner to per-6-iodo-CDs using p

A new and expeditious synthesis of all enantiomerically pure stereoisomers of rosaprostol, an antiulcer drug

• Wiesława Perlikowska,
• Remigiusz Żurawiński and
• Marian Mikołajczyk

Beilstein J. Org. Chem. 2016, 12, 2234–2239, doi:10.3762/bjoc.12.215

• rosaprostol methyl esters (−)-9 and (+)-9 in yields higher than 90%. Then the esters 9 were subjected to a Mitsunobu esterification under standard conditions (THF, rt) using p-nitrobenzoic acid (PNBA), triphenylphosphine and diisopropyl azodicarboxylate (DIAD). The p-nitrobenzoic acid esters (+)-10 and (−)-10

Palladium-catalyzed ring-opening reactions of cyclopropanated 7-oxabenzonorbornadiene with alcohols

• Katrina Tait,
• Oday Alrifai,
• Rebecca Boutin,
• Jamie Haner and
• William Tam

Beilstein J. Org. Chem. 2016, 12, 2189–2196, doi:10.3762/bjoc.12.209

• unsuccessful, palladium(II) catalysts in the absence of a triphenylphosphine ligand were more promising (Table 1, entries 6–9). The palladium(II) catalyst PdCl2(CH3CN)2 generated a high yield of substituted naphthalene 11a after only 24 hours and was chosen to further optimize reaction conditions. When the

• catalyst equivalency was investigated, lowering the catalyst from 10 mol % to 5 mol % reduced the yield from 89% to 27% (Table 1, entry 10) while further reducing the catalyst equivalency to 2 mol % showed no reaction (Table 1, entry 11). To confirm that the presence of a triphenylphosphine ligand would

• result in no reaction, the optimized catalyst was used with an external source of triphenylphosphine, which resulted in no reaction (Table 1, entry 12). To expand the scope of catalyst, the effect of using a platinum catalyst was investigated. The use of a platinum(IV) catalyst resulted in no reaction