Pyridine-promoted dediazoniation of aryldiazonium tetrafluoroborates: Application to the synthesis of SF₅-substituted phenylboronic esters and iodobenzenes

• George Iakobson,
• Junyi Du,
• Alexandra M. Z. Slawin and
• Petr Beier

Beilstein J. Org. Chem. 2015, 11, 1494–1502, doi:10.3762/bjoc.11.162

• 10.3762/bjoc.11.162 Abstract Pyridine promotes dediazoniation of aryldiazonium tetrafluoroborates. The formed aryl radicals were trapped with B2pin2, iodine, or tetrahydrofuran to afford boronic esters, iodobenzenes and benzenes, respectively. The application to the synthesis of (pentafluorosulfanyl

Deproto-metallation of N-arylated pyrroles and indoles using a mixed lithium–zinc base and regioselectivity-computed CH acidity relationship

• Mohamed Yacine Ameur Messaoud,
• Ghenia Bentabed-Ababsa,
• Madani Hedidi,
• Aïcha Derdour,
• Floris Chevallier,
• Yury S. Halauko,
• Oleg A. Ivashkevich,
• Vadim E. Matulis,
• Laurent Picot,
• Valérie Thiéry,
• Thierry Roisnel,
• Vincent Dorcet and
• Florence Mongin

Beilstein J. Org. Chem. 2015, 11, 1475–1485, doi:10.3762/bjoc.11.160

• hexane (thermodynamic conditions) [11][12] or (ii) with butyllithium activated by potassium tert-butoxide (LICKOR) in tetrahydrofuran (THF) at −75 °C [11][13]. N-Arylpyrroles substituted on their six-membered ring by methoxy [14], halogen [15][16], alkyl [17][18], or trifluoromethyl [19][20] groups have

Antioxidant potential of curcumin-related compounds studied by chemiluminescence kinetics, chain-breaking efficiencies, scavenging activity (ORAC) and DFT calculations

• Adriana K. Slavova-Kazakova,
• Silvia E. Angelova,
• Timur L. Veprintsev,
• Petko Denev,
• Davide Fabbri,
• Maria Antonietta Dettori,
• Maria Kratchanova,
• Vladimir V. Naumov,
• Aleksei V. Trofimov,
• Rostislav F. Vasil’ev,
• Giovanna Delogu and
• Vessela D. Kancheva

Beilstein J. Org. Chem. 2015, 11, 1398–1411, doi:10.3762/bjoc.11.151

• solution of potassium tert-butoxide (1.75 g, 15.6 mmol) in tetrahydrofuran (20 mL) was added dropwise a solution of dehydrozingerone (2, 1 g, 5.2 mmol) in THF (15 mL) at room temperature under N2 atmosphere. The reaction mixture was stirred at room temperature for 10 min. Diethyl oxalate (1.1 mL, 7.8 mmol

• -hydroxy-4-oxohexa-2,5-dienoate) (8) To a solution of sodium ethoxide (1.1 g, 15.7 mmol) in tetrahydrofuran (20 mL) was added dropwise a solution of 6 (1 g, 2.6 mmol) in THF (15 mL) at room temperature under an N2 atmosphere. The reaction mixture was stirred at room temperature for 10 min. Diethyl oxalate

Spiro annulation of cage polycycles via Grignard reaction and ring-closing metathesis as key steps

• Sambasivarao Kotha,
• Mohammad Saifuddin,
• Rashid Ali and
• Gaddamedi Sreevani

Beilstein J. Org. Chem. 2015, 11, 1367–1372, doi:10.3762/bjoc.11.147

• structure of 7. Synthesis of hexacyclic cage dione 10. Synthesis of tetrahydrofuran-based cage compounds 12 and 13. Synthesis di-allyl cage compound 11. Synthesis of spiro-pyrano cage molecules 7 and 17. Synthesis of octacyclic cage compound 18 via intramolecular DA reaction. Attempted synthesis to cage

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

• , 1,3-cyclododecadiene (337) was reacted with maleic anhydride to give the DA product 338 (21%). Later, the DA adduct 338 was heated under reflux in 10% aq tetrahydrofuran to afford the diacid, which on decarboxylation in the presence of lead tetraacetate in a toluene/pyridine mixture delivered compound

Design and synthesis of fused polycycles via Diels–Alder reaction and ring-rearrangement metathesis as key steps

• Sambasivarao Kotha and
• Ongolu Ravikumar

Beilstein J. Org. Chem. 2015, 11, 1259–1264, doi:10.3762/bjoc.11.140

• -sensitive reagents or catalysts were performed in degassed solvents. Dry tetrahydrofuran (THF) and dry ether were obtained by distillation over sodium benzophenone ketyl freshly prior to use. Dichloromethane (DCM) and toluene were distilled over P2O5 and DMF over CaH2. Sodium sulfate was dried in an oven at

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

• -free conditions as recently reported [27]. Hence, as a starting point, we followed the same sample preparation conditions as previously with the OPE3-dithiol [27]. We prepared 0.1–1 mM solutions of compound 5 in both 1,2,4-trichlorobenzene (TCB) or mesitylene/tetrahydrofuran (Mes/THF 4:1), and exposed

Copper ion salts of arylthiotetrathiafulvalenes: synthesis, structure diversity and magnetic properties

• Longfei Ma,
• Jibin Sun,
• Xiaofeng Lu,
• Shangxi Zhang,
• Hui Qi,
• Lei Liu,
• Yongliang Shao and
• Xiangfeng Shao

Beilstein J. Org. Chem. 2015, 11, 850–859, doi:10.3762/bjoc.11.95

• reaction with CuBr2. The reaction of 1–7 with CuBr2 was performed in the mixed solvent of tetrahydrofuran–acetonitrile (THF–CH3CN; v/v, 1:1) at room temperature. In the low concentration (<10−4 mol L−1), a dark green solution was formed, indicating the oxidation of 1–7 by CuBr2. When the concentration of

• (Shanghai, China). Tetrahydrofuran (THF) and acetonitrile (CH3CN) were distilled over CaH2 and stored under N2 atomsphere. Compounds 1–7 were synthesized by following our previous reports [37][38]. The electrochemical properties of 1–7 were recorded on a RST 5000 electrochemical workstation at a scan rate

Synthesis of 1,2-cis-2-C-branched aryl-C-glucosides via desulfurization of carbohydrate based hemithioacetals

• Henok H. Kinfe,
• Fanuel M. Mebrahtu,
• Mandlenkosi M. Manana,
• Kagiso Madumo and
• Mokela S. Sokamisa

Beilstein J. Org. Chem. 2015, 11, 583–588, doi:10.3762/bjoc.11.64

• desulfurizing agents but starting with the same hemithioacetal 3 substrate as it was originally proposed. To our delight, treatment of a solution of hemithioacetal 3a and nickel chloride hexahydrate in a mixture of methanol and tetrahydrofuran with sodium borohydride at 0 °C following the protocol reported by

Further exploration of the heterocyclic diversity accessible from the allylation chemistry of indigo

• Alireza Shakoori,
• John B. Bremner,
• Mohammed K. Abdel-Hamid,
• Anthony C. Willis,
• Rachada Haritakun and
• Paul A. Keller

Beilstein J. Org. Chem. 2015, 11, 481–492, doi:10.3762/bjoc.11.54

• ']diindolones from Nb-acyl-L-tryptophanamides [5]. Modelled structure (Spartan 10, v1.1.0, Wavefunction Inc) of bridged indigo-tetrahydrofuran product 22. Left: top view showing the tetrahydrofuran ring sitting directly over the indigo skeleton (vertical), which itself is twisted from planarity. Middle: front

• 31 (ball and stick representation). ORTEP data for 31 is given in Supporting Information File 1. Calculated values of ΔHf of the red diindolone substrate 10 and the bridged tetrahydrofuran product 22, plus the distance between nucleophile (O) and electrophile (C) in the proposed key reaction

Matsuda–Heck reaction with arenediazonium tosylates in water

• Ksenia V. Kutonova,
• Marina E. Trusova,
• Andrey V. Stankevich,
• Pavel S. Postnikov and
• Victor D. Filimonov

Beilstein J. Org. Chem. 2015, 11, 358–362, doi:10.3762/bjoc.11.41

• cinnamates were synthesized by the O-alkylation of cinnamic acids with dihaloalkanes or haloalkyl alcohols [14][16][18] or by the ring opening of tetrahydrofuran with cinnamic acid anhydrides or haloanhydrides, catalyzed by yttrium trichloride [19], titanium chloride, stannic chloride or allylsamarium

Synthesis of the furo[2,3-b]chromene ring system of hyperaspindols A and B

• Danielle L. Paterson and
• David Barker

Beilstein J. Org. Chem. 2015, 11, 265–270, doi:10.3762/bjoc.11.29

• previously reported the formation of a number of diaryl tetrahydrofuran lignans under acidic or buffered conditions utilising the high reactivity of electron-rich benzylic alcohols to assist in the rapid and high yielding formation of the tetrahydrofuran ring [13][14][15][16][17][18]. The two

Electrochemical selenium- and iodonium-initiated cyclisation of hydroxy-functionalised 1,4-dienes

• Philipp Röse,
• Steffen Emge,
• Jun-ichi Yoshida and
• Gerhard Hilt

Beilstein J. Org. Chem. 2015, 11, 174–183, doi:10.3762/bjoc.11.18

• 10.3762/bjoc.11.18 Abstract The cobalt(I)-catalysed 1,4-hydrovinylation reaction of allyloxytrimethylsilane and allyl alcohol with substituted 1,3-dienes leads to hydroxy-functionalised 1,4-dienes in excellent regio- and diastereoselective fashion. Those 1,4-dienols can be converted into tetrahydrofuran

• are in turn potential substrates for the synthesis of functionalised heterocycles. Particularly, we were interested in the synthesis of tetrahydrofuran and pyran derivatives. Those heterocycles are prevalent substructures in many natural compounds, pesticides and drugs with antifungal and

• antibacterial properties [10][11][12][13]. For this purpose, we investigated a protocol for the straight forward synthesis of 1,4-dienols which should be cyclised into the corresponding tetrahydrofuran or pyran derivatives. With our sight set on efficient and atom economic organic reactions electrochemistry

Cross-dehydrogenative coupling for the intermolecular C–O bond formation

• Igor B. Krylov,
• Vera A. Vil’ and
• Alexander O. Terent’ev

Beilstein J. Org. Chem. 2015, 11, 92–146, doi:10.3762/bjoc.11.13

• , xylenes, 1,3,5-trimethylbenzene, 2,4-dichlorotoluene, and ethylbenzene. α-Acyloxy ethers 180 were synthesized by the oxidative coupling of benzyl alcohols 178 with ethers 179 (dioxane, tetrahydropyran, tetrahydrofuran, 1,2-dimethoxyethane) using Cu(OAc)2/t-BuOOH system [152] (Scheme 37). In a series of

Multicomponent versus domino reactions: One-pot free-radical synthesis of β-amino-ethers and β-amino-alcohols

• Bianca Rossi,
• Nadia Pastori,
• Simona Prosperini and
• Carlo Punta

Beilstein J. Org. Chem. 2015, 11, 66–73, doi:10.3762/bjoc.11.10

• -toluidine, tetrahydrofuran (THF) and acetone in the presence of the TiCl4/Zn system as a model reaction. The reaction occurred when adding a solution of t-BuOOH in THF dropwise into the reaction mixture. The different process conditions, resulting in the synthesis of 1a, are reported in Table 1. As

A one-pot multistep cyclization yielding thiadiazoloimidazole derivatives

• Debabrata Samanta,
• Anup Rana,
• Jan W. Bats and
• Michael Schmittel

Beilstein J. Org. Chem. 2014, 10, 2989–2996, doi:10.3762/bjoc.10.317

• dimensions 0.08 × 0.10 × 0.60 mm) was measured on a Siemens SMART 1K CCD diffractometer at a temperature of about −87 °C. General procedure for the preparation of dithiourea 1a–c. A solution of o-phenylenediamine (2.00 g, 18.5 mmol) and the corresponding isothiocyanate (37.0 mmol) in tetrahydrofuran (100 mL

Recent advances in the electrochemical construction of heterocycles

• Robert Francke

Beilstein J. Org. Chem. 2014, 10, 2858–2873, doi:10.3762/bjoc.10.303

• alcohol nucleophile, a variety of tetrahydrofuran, tetrahydropyran and oxepane structures 4 can be synthesized (Scheme 2, X = O) [34]. The reaction is initiated by single electron oxidation to generate intermediate 2, which after cyclization and deprotonation gives radical 3. Further oxidation results in

Synthesis and properties of novel star-shaped oligofluorene conjugated systems with BODIPY cores

• Clara Orofino-Pena,
• Diego Cortizo-Lacalle,
• Joseph Cameron,
• Muhammad T. Sajjad,
• Pavlos P. Manousiadis,
• Neil J. Findlay,
• Alexander L. Kanibolotsky,
• Dimali Amarasinghe,
• Peter J. Skabara,
• Tell Tuttle,
• Graham A. Turnbull and
• Ifor D. W. Samuel

Beilstein J. Org. Chem. 2014, 10, 2704–2714, doi:10.3762/bjoc.10.285

• solvents (dichloromethane, tetrahydrofuran, toluene, hexane and diethyl ether) were obtained from a solvent purification system (SPS 400, innovative technologies) using alumina as the drying agent; any other dry solvents were purchased from Sigma-Aldrich. 1H and 13C NMR spectra were recorded on a Bruker

Microsolvation and sp²-stereoinversion of monomeric α-(2,6-di-tert-butylphenyl)vinyllithium as measured by NMR

• Rudolf Knorr,
• Monika Knittl and
• Eva C. Rossmann

Beilstein J. Org. Chem. 2014, 10, 2521–2530, doi:10.3762/bjoc.10.263

• its mixture with aggregates. On the other hand, the analytic characterization of such a reactive species may be problematic due to a diminished kinetic stability against certain solvents, especially tetrahydrofuran (THF). For instance, barely avoidable decomposition products may interfere with

Indium-mediated allylation in carbohydrate synthesis: A short and efficient approach towards higher 2-acetamido-2-deoxy sugars

• Christopher Albler,
• Ralph Hollaus,
• Hanspeter Kählig and
• Walther Schmid

Beilstein J. Org. Chem. 2014, 10, 2230–2234, doi:10.3762/bjoc.10.231

• intramolecular Michael addition, leading to the formation of highly substituted tetrahydrofuran derivatives of the C-glycoside type [31]. Next, we investigated the azide reduction of compounds 6a–c under different reaction conditions. Unfortunately DTT/DIPA, thioacetic acid, tributylphosphine/H2O and H2/Pd

Chiral phosphines in nucleophilic organocatalysis

• Yumei Xiao,
• Zhanhu Sun,
• Hongchao Guo and
• Ohyun Kwon

Beilstein J. Org. Chem. 2014, 10, 2089–2121, doi:10.3762/bjoc.10.218

• dichloromethane or tetrahydrofuran, the reaction of disubstituted ketenes and N-tosyl arylimines provided corresponding trans-β-lactams in moderate to excellent ee (up to 98%), diastereoselectivities (up to 99:1 dr), and yields (up to >99%). Of particular interest, this methodology facilitates the formation of

Palladium-catalysed cyclisation of alkenols: Synthesis of oxaheterocycles as core intermediates of natural compounds

• Miroslav Palík,
• Jozef Kožíšek,
• Peter Koóš and
• Tibor Gracza

Beilstein J. Org. Chem. 2014, 10, 2077–2086, doi:10.3762/bjoc.10.216

• sizes are found in many different biologically active compounds. Particularly, substituted tetrahydrofuran units are present in a large branch of natural products that display interesting biological properties, such as goniofufurone 1 [1], goniothalesdiol 2 [2], varitriol 3 [3], erythroskyrine 4 [4][5

• ) afforded surprisingly tetrahydrofuran derivative 46 as a product of a Wacker-type cyclisation. Interestingly, the reactions of alkenols having an additional allylic OR group provided only products of type II. Thus, diastereomeric mixtures of vinyltetrahydrofurans 47, 48 (Table 1, entry 6), 49, 50 (Table 1

• regeneration of the PdII-catalyst via cleavage of the C–OR bond (Scheme 6). Surprisingly, the reaction of 1,1-disubstituted alkenes 30, 35 (Table 1, entries 10 and 9) provided only chlorinated tetrahydropyran (type III) and tetrahydrofuran (type IV) derivatives. The chloroderivatives III and IV were probably

Macrocyclic bis(ureas) as ligands for anion complexation

• Claudia Kretschmer,
• Gertrud Dittmann and
• Johannes Beck

Beilstein J. Org. Chem. 2014, 10, 1834–1839, doi:10.3762/bjoc.10.193

• (urea) ring. The ammonium ions are located in the saddle shaped cavity formed by the twisted bis(urea). The binding properties of 1 and 2 towards anions were studied by 1H NMR spectroscopy. As 2 was sufficiently soluble, tetrahydrofuran (THF) turned out as a suitable solvent for the spectroscopic

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

• with samarium diiodide was then performed in a methanol/tetrahydrofuran mixture in which compound 26 was scarcely soluble. Gratifyingly, after one hour reaction time and purification by column chromatography aminopyran 22 was isolated in 30% yield. Interestingly, no cyclization product similar to 24

Convergent synthetic methodology for the construction of self-adjuvanting lipopeptide vaccines using a novel carbohydrate scaffold

• Vincent Fagan,
• Istvan Toth and
• Pavla Simerska

Beilstein J. Org. Chem. 2014, 10, 1741–1748, doi:10.3762/bjoc.10.181

• removed during work-up. The residue was alkylated with sodium hydride and propargyl bromide in dry tetrahydrofuran (THF) to give intermediate 7, which was not isolated. The methoxy ester was hydrolyzed in situ by addition of sodium hydroxide. Acid–base extraction and purification by flash chromatography