1H-Imidazol-4(5H)-ones and thiazol-4(5H)-ones as emerging pronucleophiles in asymmetric catalysis

• Antonia Mielgo and
• Claudio Palomo

Beilstein J. Org. Chem. 2016, 12, 918–936, doi:10.3762/bjoc.12.90

• ureidopeptide-like bifunctional Brønsted base catalyst C5 [85]. Ureidopeptide-like Brønsted base bifunctional catalyst preparation. NMM = N-methylmorpholine, THF = tetrahydrofuran [85]. Selected examples of the Michael addition of thiazolones to different nitroolefins promoted by catalyst C5 [85]. Elaboration

Enantioselective carbenoid insertion into C(sp³)–H bonds

• J. V. Santiago and
• A. H. L. Machado

Beilstein J. Org. Chem. 2016, 12, 882–902, doi:10.3762/bjoc.12.87

• stereogenic center is formed on the carbenoid carbon coordinated to the metal rhodium center and not on carbon-containing the C(sp3)–H bond activated by the carbenoid moiety. The authors also reported in this work the insertion into the C(sp3)–H bond of tetrahydrofuran. This reaction showed good yield, regio

• in C(sp3)–H bonds in a diastereo- and enantioselective manner. For enantioselective insertion reactions the authors tested two specific iridium complexes, 61a and 61b. The authors used a wide range of α-substituted α-diazoacetates for performing insertion into substrates such as tetrahydrofuran (24

• low temperatures to affords the product in high yields and enantioselectivity (Scheme 12). The same catalytic system was applied to carbenoid insertions into tetrahydrofuran C(sp3)–H bonds (Scheme 13). The reaction afforded the desired product in a regioselective way and high diastereoselectivity

Scope and mechanism of the highly stereoselective metal-mediated domino aldol reactions of enolates with aldehydes

• M. Emin Cinar,
• Bernward Engelen,
• Martin Panthöfer,
• Hans-Jörg Deiseroth,
• Jens Schlirf and
• Michael Schmittel

Beilstein J. Org. Chem. 2016, 12, 813–824, doi:10.3762/bjoc.12.80

• benzaldehyde (3a: Ar = Ph) (Scheme 2). The enolate was generated from propiophenone by deprotonation with lithium diisopropylamide (LDA) at −40 °C in tetrahydrofuran (THF) and was subsequently reacted with 0.33 equivalents of MCl3 or 0.25 equivalents of MCl4, respectively. The resulting metal enolate was then

Asymmetric α-amination of 3-substituted oxindoles using chiral bifunctional phosphine catalysts

• Qiao-Wen Jin,
• Zhuo Chai,
• You-Ming Huang,
• Gang Zou and
• Gang Zhao

Beilstein J. Org. Chem. 2016, 12, 725–731, doi:10.3762/bjoc.12.72

• influence of solvents and reaction temperature on the reaction were investigated with the best catalyst (Table 2). The use of both polar solvents (ethyl ether, tetrahydrofuran, acetone, acetonitrile or ethyl alcohol) including other chlorinated solvents such as chloroform, 1,2-dichloroethane and 1,1,2

Versatile deprotonated NHC: C,N-bridged dinuclear iridium and rhodium complexes

• Albert Poater

Beilstein J. Org. Chem. 2016, 12, 117–124, doi:10.3762/bjoc.12.13

• functional [82]. Solvent effects, using either tetrahydrofuran, dichloromethane or toluene, were calculated with the polarizable continuous solvation model polarizable continuum model (PCM) model [83][84], and non-electrostatic terms were also included. The cavity is created via a series of overlapping

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

• with the concerted C2–C6 (DA) pathway, opening new venues for the preparation of heterocycles from carbodiimides [54]. Experimental General methods. Anhydrous solvents were used to perform reactions under inert atmosphere (argon). Potassium was utilized to dry tetrahydrofuran (THF) and toluene

Iron complexes of tetramine ligands catalyse allylic hydroxyamination via a nitroso–ene mechanism

• David Porter,
• Belinda M.-L. Poon and
• Peter J. Rutledge

Beilstein J. Org. Chem. 2015, 11, 2549–2556, doi:10.3762/bjoc.11.275

• commercially available reagents were used without purification unless otherwise specified. Solvents for extraction and chromatography were distilled before use. Solvents for reactions were freshly distilled immediately prior to use. Tetrahydrofuran (THF) was dried over sodium wire and benzophenone

Urethane tetrathiafulvalene derivatives: synthesis, self-assembly and electrochemical properties

• Xiang Sun,
• Guoqiao Lai,
• Zhifang Li,
• Yuwen Ma,
• Xiao Yuan,
• Yongjia Shen and
• Chengyun Wang

Beilstein J. Org. Chem. 2015, 11, 2343–2349, doi:10.3762/bjoc.11.255

• by 1H NMR, 13C NMR, and EIMS. Self-assembly and SEM investigation of T1 and T2 The studies showed that T1 and T2 gels were not formed in several common solvents such as hexane, chloroform, dichloromethane, tetrahydrofuran, toluene, diethyl ether, acetone, dimethylformamide, ethanol, methanol and

Lewis acid-promoted hydrofluorination of alkynyl sulfides to generate α-fluorovinyl thioethers

• Davide Bello and
• David O'Hagan

Beilstein J. Org. Chem. 2015, 11, 1902–1909, doi:10.3762/bjoc.11.205

• % yield (Table 2, entry 8). When tetrahydrofuran or dichloroethane were explored as solvents the conversions were low, even when warming (tetrahydrofuran, Table 2, entry 9, dichloroethane, Table 2, entries 10–12). For the TiF4/3HF·Et3N reactions (Table 3) shorter reaction times also afforded lower

• conversions, and sub-stoichiometric levels of TiF4 failed to initiate the reaction. Tetrahydrofuran and dichloroethane at different temperatures were again not useful solvents. Having optimised the reaction to some extent with substrate 1a, a range of alkynyl sulfides [15] were now prepared and each

Preparation of conjugated dienoates with Bestmann ylide: Towards the synthesis of zampanolide and dactylolide using a facile linchpin approach

• Jingjing Wang,
• Samuel Z. Y. Ting and
• Joanne E. Harvey

Beilstein J. Org. Chem. 2015, 11, 1815–1822, doi:10.3762/bjoc.11.197

• Bestmann ylide (1 equiv) in solvent (toluene or tetrahydrofuran) heated at reflux, a solution of aldehyde (1 equiv, 1.0 M) was added. The reaction was heated at reflux until full consumption of starting material aldehyde was observed by TLC. After cooling to rt, the reaction was concentrated and purified

An efficient synthesis of N-substituted 3-nitrothiophen-2-amines

• Sundaravel Vivek Kumar,
• Shanmugam Muthusubramanian,
• J. Carlos Menéndez and
• Subbu Perumal

Beilstein J. Org. Chem. 2015, 11, 1707–1712, doi:10.3762/bjoc.11.185

• carbonate as the optimal base in refluxing ethanol (93% yield), alternative solvents such as methanol (Table 1, entry 13), N,N-dimethylformamide (Table 1, entry 14), acetonitrile (Table 1, entry 15), tetrahydrofuran (Table 1, entry 16), 1,4-dioxane (Table 1, entry 17) and water (Table 1, entry 18) were

Robust bifunctional aluminium–salen catalysts for the preparation of cyclic carbonates from carbon dioxide and epoxides

• Yuri A. Rulev,
• Zalina Gugkaeva,
• Victor I. Maleev,
• Michael North and
• Yuri N. Belokon

Beilstein J. Org. Chem. 2015, 11, 1614–1623, doi:10.3762/bjoc.11.176

• GPCsystem. Elution was with tetrahydrofuran at 1 mL/min with a column temperature of 23 °C and detection by refractive index. 20 µL of a 1 mg/mL sample in THF was injected for each measurement and eluted for 40 minutes. Calibration was carried out in the molecular weight range 400–2 × 106 Da using ReadyCal

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