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

• material, a Wittig reaction was chosen as an alternative. The Wittig reaction approach is shown in Scheme 2. In this reaction, phosphonium salt 7 was prepared in quantitative yield from 5 and triphenylphosphine by reflux in toluene, according to a procedure reported for dimethoxybenzyl chloride [21]. The

Pyridylidene ligand facilitates gold-catalyzed oxidative C–H arylation of heterocycles

• Kazuhiro Hata,
• Hideto Ito,
• Yasutomo Segawa and
• Kenichiro Itami

Beilstein J. Org. Chem. 2015, 11, 2737–2746, doi:10.3762/bjoc.11.295

• strongest electron-donating N-heterocyclic carbenes, resulted in the rate acceleration of the C–H arylation reaction of heterocycles over conventional ligands such as triphenylphosphine and a classical N-heterocyclic carbene. In situ observation and isolation of the 2-pyridylidene-gold(III) species, as well

• such oxidative reaction conditions. For example, triphenylphosphine is easily oxidized to triphenylphosphine oxide by a hypervalent iodine reagent that has been used as an oxidant for gold-catalyzed C–H arylation [69]. Appropriate ligands that are tolerant to the oxidative conditions would offer

• reactions, we hypothesize that the highly electron-donating PyC ligand facilitates the oxidation of gold(I) to gold(III). As triphenylphosphine is known to be easily oxidized to triphenylphosphine oxide under the current oxidative conditions, the ligand-free gold(III) species is thought to be an active

Synthesis and photophysical characteristics of polyfluorene polyrotaxanes

• Aurica Farcas,
• Giulia Tregnago,
• Ana-Maria Resmerita,
• Pierre-Henri Aubert and
• Franco Cacialli

Beilstein J. Org. Chem. 2015, 11, 2677–2688, doi:10.3762/bjoc.11.288

• the generation of active layers in organic electronic devices. Experimental Materials and methods 1, 2, tetrakis(triphenylphosphine)palladium(0) [Pd(PPh3)4], β- and γCD, bromobenzene (Br–Ph), dimethylformamide (DMF), dimethyl sulfoxide (DMSO), and quinine sulfate dehydrate in 0.5 M sulfuric acid were

Versatile synthesis and biological evaluation of novel 3’-fluorinated purine nucleosides

• Hang Ren,
• Haoyun An,
• Paul J. Hatala,
• William C. Stevens Jr,
• Jingchao Tao and
• Baicheng He

Beilstein J. Org. Chem. 2015, 11, 2509–2520, doi:10.3762/bjoc.11.272

• and Suzuki reaction conditions. To this end, 2-(tributylstannyl)furan was coupled with 6-chloropurine nucleoside 26 by Stille cross coupling [47][48] catalyzed by bis(triphenylphosphine)palladium(II) chloride in DMF (Method I) (Scheme 3). The resulting 6-aryl compound 30 was obtained in 91% yield and

• synthesize compounds 6–15. The 6-chloropurine intermediate 26 was coupled with 3-thienylboronic acid and phenylboronic acid catalyzed by tetrakis(triphenylphosphine)palladium (Pd(PPh3)4) in toluene (Method II), resulting in the desired protected intermediates 31 and 32 in 56% and 52% yields, respectively

• and deprotection of 2,6-dichloropurine 42 was achieved with a saturated solution of ammonia in methanol to furnish 2-chloro-3’-deoxy-3’-fluoroadenosine (16). The 2,6-dichloro-intermediate 42 was coupled with 2-(tributylstannyl)furan catalyzed by bis(triphenylphosphine)palladium(II) chloride in DMF to

Cu(I)-catalyzed N,N’-diarylation of natural diamines and polyamines with aryl iodides

• Svetlana P. Panchenko,
• Alexei D. Averin,
• Maksim V. Anokhin,
• Olga A. Maloshitskaya and
• Irina P. Beletskaya

Beilstein J. Org. Chem. 2015, 11, 2297–2305, doi:10.3762/bjoc.11.250

• % (Table 1, entry 3). Diarylation of putrescine (2), on contrary, was more successful in the presence of the CuI/L1/EtCN catalytic system (Table 1, entry 4), and a similar result was obtained when using L2 together with Ph3P (Table 1, entry 6), while employing L1 with triphenylphosphine led to a low

• (Table 2, entry 7). The same catalytic system with or without triphenylphosphine was not efficient in the coupling with 4-iodobiphenyl, however, the use of L1 gave rise to the target diaryl derivative 19 in a moderate yield (Table 2, entry 8). On contrary, application of the ligand L2 was more successful

Synthesis of D-fructose-derived spirocyclic 2-substituted-2-oxazoline ribosides

• Madhuri Vangala and
• Ganesh P. Shinde

Beilstein J. Org. Chem. 2015, 11, 2289–2296, doi:10.3762/bjoc.11.249

• glycosyl azides via intramolecular condensation with a vicinal ester group in the presence of triphenylphosphine [27] or from the reaction of D-glucals with N-iodosuccinimide and amides [28][29]. Alternatively, 5 can be derived by a Ritter-like [30][31] transformation, involving trapping of the

Stereoselective synthesis of hernandulcin, peroxylippidulcine A, lippidulcines A, B and C and taste evaluation

• Marco G. Rigamonti and
• Francesco G. Gatti

Beilstein J. Org. Chem. 2015, 11, 2117–2124, doi:10.3762/bjoc.11.228

• ]. Indeed, the treatment of (–)-isopulegol with diisopropyl azodicarboxylate (DIAD) and p-nitrobenzoic acid in the presence of triphenylphosphine gave the corresponding ester in an almost quantitative yield. The latter was easily purified by crystallization from n-hexane, and then transesterificated with

• -up followed by treatment of the reaction mixture with triphenylphosphine, the unreacted lippidulcines B and C were oxidized with MnO2 to give ketone 14 together to the unreacted O-TMS protected lippidulcine A, 15a ([α]D −11.3° (c 1.0, CHCl3)). The latter were easily separated by column chromatography

A new approach to ferrocene derived alkenes via copper-catalyzed olefination

• Vasily M. Muzalevskiy,
• Aleksei V. Shastin,
• Alexandra D. Demidovich,
• Namiq G. Shikhaliev,
• Abel M. Magerramov,
• Victor N. Khrustalev,
• Rustem D. Rakhimov,
• Sergey Z. Vatsadze and
• Valentine G. Nenajdenko

Beilstein J. Org. Chem. 2015, 11, 2072–2078, doi:10.3762/bjoc.11.223

• –Fuchs reaction) using a 2–4-fold molar excess of triphenylphosphine [27][28][29][30][31]. Results and Discussion Synthesis of halovinylferrocenes A few years ago we discovered a new reaction for a double carbon–carbon bond formation – the reaction of catalytic olefination. It was shown that the copper

Investigation on the reactivity of α-azidochalcones with carboxylic acids: Formation of α-amido-1,3-diketones and highly substituted 2-(trifluoromethyl)oxazoles

• Kandasamy Rajaguru,
• Arumugam Mariappan,
• Rajendran Suresh,
• Periasamy Manivannan and
• Shanmugam Muthusubramanian

Beilstein J. Org. Chem. 2015, 11, 2021–2028, doi:10.3762/bjoc.11.219

• . This is illustrated with one reaction in which 3 was subjected to treatment with triphenylphosphine in the presence of iodine and triethylamine in dry dichloromethane at room temperature (Scheme 4) [34][35]. As expected, compounds 3 are converted to 2,4,5-substituted oxazole 7 regiospecifically in good

• allowing the reaction mixture to cool to room temperature, ice-cold water was added. The precipitate obtained was filtered, dried in vacuum and recrystallized from ethanol to afford 3e (yield: 1.93 g; 88%). Synthesis of 7: To a stirred solution of triphenylphosphine (2.0 equiv) and iodine in

New aryloxybenzylidene ruthenium chelates – synthesis, reactivity and catalytic performance in ROMP

• Patrycja Żak,
• Szymon Rogalski,
• Mariusz Majchrzak,
• Maciej Kubicki and
• Cezary Pietraszuk

Beilstein J. Org. Chem. 2015, 11, 1910–1916, doi:10.3762/bjoc.11.206

• Grubbs catalysts bearing a triphenylphosphine ligand (or its para-substituted analogues) by metathesis exchange with substituted 2-vinylphenols. The complexes behave like a latent catalyst and are characterized by an improved catalytic behaviour as compared to that of the known analogues, i.e., they

• donating and electron withdrawing substituents at the benzylidene ligand in para position to the coordinating oxygen and bearing instead of a strong sigma-donor ligand – tricyclohexylphosphine a weaker sigma-donor – a triphenylphosphine ligand or its derivatives. The catalytic performance of the

• synthesized complexes were tested in ROMP of COD and a single selected norbornene derivative. Results and Discussion Synthesis Complexes containing triphenylphosphine ligands and substituted triphenylphosphine ligands were isolated in high yields (95–98%) according to the methodology described by Grubbs

Synthesis and structures of ruthenium–NHC complexes and their catalysis in hydrogen transfer reaction

• Chao Chen,
• Chunxin Lu,
• Qing Zheng,
• Shengliang Ni,
• Min Zhang and
• Wanzhi Chen

Beilstein J. Org. Chem. 2015, 11, 1786–1795, doi:10.3762/bjoc.11.194

• displaying the typical octahedral geometry. The reaction of [RuL1(CH3CN)4](PF6)2 with triphenylphosphine and 1,10-phenanthroline resulted in the substitution of one and two coordinated acetonitrile ligands and afforded [RuL1(PPh3)(CH3CN)3](PF6)2 (4) and [RuL1(phen)(CH3CN)2](PF6)2 (5), respectively. The

• complexes show good catalytic activity in the transfer hydrogenation of ketones. The reaction of acetonitrile-coordinated Ru–NHC complex 2 with other donors such as triphenylphosphine and 1,10-phenanthroline was also studied. Results and Discussion Synthesis and characterization of [Ru(L1)2(CH3CN)2](PF6)2

• triphenylphosphine and 1,10-phenanthroline The coordinated acetonitrile ligands could be easily replaced by various N- and P-donors [22]. The reactions of the acetonitrile-coordinated Ru–NHC complexes with other ligands were studied. The reaction of complex 2 with an excess of triphenylphosphine and 1,10

A new method for the synthesis of α-aminoalkylidenebisphosphonates and their asymmetric phosphonyl-phosphinyl and phosphonyl-phosphinoyl analogues

• Anna Kuźnik,
• Roman Mazurkiewicz,
• Mirosława Grymel,
• Katarzyna Zielińska,
• Jakub Adamek,
• Ewa Chmielewska,
• Marta Bochno and
• Sonia Kubica

Beilstein J. Org. Chem. 2015, 11, 1418–1424, doi:10.3762/bjoc.11.153

• too low electrophilic activity of the α-carbon atom of the removed 1-methoxyalkylphosphonic acid derivatives. However, the electrophilic activity of the latter compounds was enough for their reaction with triphenylphosphine. Therefore, to enhance the electrophilic activity of the discussed 1

New palladium–oxazoline complexes: Synthesis and evaluation of the optical properties and the catalytic power during the oxidation of textile dyes

• Rym Hassani,
• Mahjoub Jabli,
• Yakdhane Kacem,
• Jérôme Marrot,
• Damien Prim and
• Béchir Ben Hassine

Beilstein J. Org. Chem. 2015, 11, 1175–1186, doi:10.3762/bjoc.11.132

• cyclopalladated complexes Synthesis of (S)-chloro-[(4-isopropyloxazolinyl)-2-naphthyl](triphenylphosphine)palladium(II) (5): The complex (3) was synthesized using two methods: Method A: A mixture of Pd(OAc)2 (50 mg, 0.22 mmol, 1 equiv), AcONa (18.3 mg, 0.22 mmol, 1 equiv) and (S)-4-isopropyl-2-(naphthalen-1-yl

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

• reaction we used a palladium catalyst and a copper(I) cocatalyst in the presence of triphenylphosphine and triethylamine as the base. The carboxylic acids were then submitted to a gold-catalyzed cyclization reaction (Table 2). The optimized reaction conditions for cyclization was employed for pyrrole- and

Hydrogenation of unactivated enamines to tertiary amines: rhodium complexes of fluorinated phosphines give marked improvements in catalytic activity

• Sergey Tin,
• Tamara Fanjul and
• Matthew L. Clarke

Beilstein J. Org. Chem. 2015, 11, 622–627, doi:10.3762/bjoc.11.70

• Abstract In the hydrogenation of sluggish unactivated enamine substrates, Rh complexes of electron-deficient phosphines are demonstrated to be far more reactive catalysts than those derived from triphenylphosphine. These operate at low catalyst loadings (down to 0.01 mol %) and are able to reduce

• enhance the rate of Rh catalysed hydrogenation relative to more electron donating ligands such as triphenylphosphine. The hydrogenation of enamine 1e at a S/Rh ratio of 250 at 65 °C proceeded at a suitable rate, such that simply measuring conversion at the times given provides a meaningful measure of the

• relative rates of hydrogenation for Rh catalysts derived from electron-donating and electron-withdrawing ligands. A screen of monodentate ligands was performed for hydrogenation of 1e with catalysts derived from ligands 4–9 (Scheme 3). Compared to triphenylphosphine, more electron-poor ligands

The Shono-type electroorganic oxidation of unfunctionalised amides. Carbon–carbon bond formation via electrogenerated N-acyliminium ions

• Alan M. Jones and
• Craig E. Banks

Beilstein J. Org. Chem. 2014, 10, 3056–3072, doi:10.3762/bjoc.10.323

• (Fmol−1) was required [20]. The authors also detail a deallylation and a debenzylation deprotection method to 108. An alternative strategy to chiral amino acids was demonstrated by Kuźnik and colleagues [98] through the electrochemical preparation of 3-triphenylphosphine-2,5-piperazinediones as chiral

First chemoenzymatic stereodivergent synthesis of both enantiomers of promethazine and ethopropazine

• Paweł Borowiecki,
• Daniel Paprocki and
• Maciej Dranka

Beilstein J. Org. Chem. 2014, 10, 3038–3055, doi:10.3762/bjoc.10.322

• (96% ee) despite using the same procedure as for the reaction between (S)-(+)-5 and PBr3. In addition, bromination of (S)-(+)-5 under Appel reaction conditions employing tetrabromomethane (CBr4) as a halide ion source used along with triphenylphosphine (Ph3P) was also investigated. Although this

(2R,1'S,2'R)- and (2S,1'S,2'R)-3-[2-Mono(di,tri)fluoromethylcyclopropyl]alanines and their incorporation into hormaomycin analogues

• Armin de Meijere,
• Sergei I. Kozhushkov,
• Dmitrii S. Yufit,
• Christian Grosse,
• Marcel Kaiser and
• Vitaly A. Raev

Beilstein J. Org. Chem. 2014, 10, 2844–2857, doi:10.3762/bjoc.10.302

• %, respectively). Upon treatment with the iodine/triphenylphosphine reagent in the presence of imidazole, the racemic trans-(2-fluoromethylcyclopropyl)methanols 25a–c were smoothly converted to the corresponding iodides 11a–c in very good yields (Scheme 3). Alkylation of the glycine equivalent enolates derived

Synthesis of the pentasaccharide repeating unit of the O-antigen of E. coli O117:K98:H4

• Pintu Kumar Mandal

Beilstein J. Org. Chem. 2014, 10, 2724–2728, doi:10.3762/bjoc.10.287

• out by treatment with triphenylphosphine [33], then the product was acetylated using acetic anhydride and pyridine to give disaccharide derivative 13 in 84% overall yield in two steps. The anomeric PMP group of compound 13 was oxidatively cleaved using ceric(IV) ammonium nitrate (CAN) [15] and the

Versatile synthesis of amino acid functionalized nucleosides via a domino carboxamidation reaction

• Vicky Gheerardijn,
• Jos Van den Begin and
• Annemieke Madder

Beilstein J. Org. Chem. 2014, 10, 2566–2572, doi:10.3762/bjoc.10.268

• protected serine to deliver product 6 in good yield and purity after recrystallization in cold diethyl ether (64%) [63]. Coupling of protected serine methyl ester 6 with TBDMS-protected nucleoside 1 in the presence of tetrakis(triphenylphosphine)palladium(0) and Et3N in THF under CO atmosphere (4 bar) gave

Synthesis of aromatic glycoconjugates. Building blocks for the construction of combinatorial glycopeptide libraries

• Markus Nörrlinger and
• Thomas Ziegler

Beilstein J. Org. Chem. 2014, 10, 2453–2460, doi:10.3762/bjoc.10.256

• nitro group was achieved with a Staudinger reaction [14]. Thus, treatment of 5 with triphenylphosphine in aqueous THF gave tert-butyl 3-aminomethyl-5-nitrobenzoate which was not isolated but immediately converted into the corresponding Fmoc-protected derivative 6 in 78% overall yield. Final

Visible light photoredox-catalyzed deoxygenation of alcohols

• Daniel Rackl,
• Viktor Kais,
• Peter Kreitmeier and
• Oliver Reiser

Beilstein J. Org. Chem. 2014, 10, 2157–2165, doi:10.3762/bjoc.10.223

• triphenylphosphine to triphenylphospine oxide and iodine to iodide, are required, which appears to be problematic for establishing a sustainable protocol that allows the recycling and reuse of the reagents involved. Herein we report a redox economic deoxygenation method of alcohols in which formation of radicals is

The effect of permodified cyclodextrins encapsulation on the photophysical properties of a polyfluorene with randomly distributed electron-donor and rotaxane electron-acceptor units

• Aurica Farcas,
• Ana-Maria Resmerita,
• Pierre-Henri Aubert,
• Flavian Farcas,
• Iuliana Stoica and
• Anton Airinei

Beilstein J. Org. Chem. 2014, 10, 2145–2156, doi:10.3762/bjoc.10.222

• these compounds for polymer light-emitting layers and photovoltaic applications are currently underway and will be reported in due course. Experimental Materials and methods 9,9-dioctylfluorene-2,7-bis(trimethyleneborate) (3), 2,7-dibromofluoren-9-one, tetrakis(triphenylphosphine) palladium(0) [Pd(PPh3

Organophosphorus chemistry

• Paul R. Hanson

Beilstein J. Org. Chem. 2014, 10, 2087–2088, doi:10.3762/bjoc.10.217

• phosphinoyl-indoles and phosphinoyl-isocoumarins and new chemistries of H-phosphonates. The Thematic Series also details work on new metathesis-based reactions of vinyl phosphonates and phosphate tethers, novel phosphorus-based ligands in asymmetric catalysis, novel rasta resin–triphenylphosphine oxides and

Pd/C-catalyzed aerobic oxidative esterification of alcohols and aldehydes: a highly efficient microwave-assisted green protocol

• Marina Caporaso,
• Giancarlo Cravotto,
• Spyros Georgakopoulos,
• George Heropoulos,
• Katia Martina and
• Silvia Tagliapietra

Beilstein J. Org. Chem. 2014, 10, 1454–1461, doi:10.3762/bjoc.10.149

• triphenylphosphine to the reaction mixture (Table 1, entry 5) only had minimal effects on substrate conversion and selectivity. Preliminary sonication of the K2CO3 in methanol, prior to adding the catalyst and the substrate, led to a significant increase in reactivity affording complete conversion and complete