Mannich base-connected syntheses mediated by ortho-quinone methides

• Petra Barta,
• Ferenc Fülöp and
• István Szatmári

Beilstein J. Org. Chem. 2018, 14, 560–575, doi:10.3762/bjoc.14.43

• 5, the catalyst gave remarkable results at room temperature in short reactions (5–30 minutes) in 90–96% yields. Comparing these results with those achieved by the application of tin dioxide nanoparticles (nano SnO2, Table 1, entry 6), molten salt catalysis affording higher yields in shorter

Aminosugar-based immunomodulator lipid A: synthetic approaches

• Alla Zamyatina

Beilstein J. Org. Chem. 2018, 14, 25–53, doi:10.3762/bjoc.14.3

Intramolecular glycosylation

• Xiao G. Jia and
• Alexei V. Demchenko

Beilstein J. Org. Chem. 2017, 13, 2028–2048, doi:10.3762/bjoc.13.201

• application, glycosyl donor precursors were reacted with phthalic anhydride to afford the corresponding esters. The activation with thionyl chloride was used for tethering the donors to the glycosyl acceptor counterpart and the regioselectivity was controlled using tin-mediated coupling under microwave

• 27 using tin-mediated primary alkylation to afford the tethered pair 28. The latter is then intramolecularly glycosylated in the presence of NIS/TfOH in 93% yield and complete stereoselectivity. The resulting cyclic compound 29 is then subjected to concomitant xylylene tether removal and

• 72. The latter was then intramolecularly glycosylated in the presence of silver triflate, tin(II) chloride, and 2,6-di-tert-butyl-4-methylpyridine (DTBMP). Finally, the tether was cleaved off using TFA to give pure 1,2-cis glycoside 73 in 63% yield over two steps. An alternative linker was developed

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

Total syntheses of the archazolids: an emerging class of novel anticancer drugs

• Stephan Scheeff and
• Dirk Menche

Beilstein J. Org. Chem. 2017, 13, 1085–1098, doi:10.3762/bjoc.13.108

• synthesis in 44% yield over 3 steps. For the final step the authors decided to follow a Stille coupling protocol established by Fürstner et al. [96] with CuTC as co-catalyst and [Ph2PO2][NBu4] as tin scavenger. Subsequently, the triene 68 could be synthesized in excellent 82% yield. For biological studies

Synthesis of 1-indanones with a broad range of biological activity

• Marika Turek,
• Dorota Szczęsna,
• Marek Koprowski and
• Piotr Bałczewski

Beilstein J. Org. Chem. 2017, 13, 451–494, doi:10.3762/bjoc.13.48

• Friedel–Crafts alkylation has been used by Ahmed et al. for the synthesis of 2-hydroxyindan-1-one derivatives 222 in good yields (Scheme 61) [90]. The same research group used the THP (tetrahydropyranyl) and MOM (methoxymethyl) protected chalcone epoxides and tin(IV) chloride under mild conditions to

The reductive decyanation reaction: an overview and recent developments

• Jean-Marc R. Mattalia

Beilstein J. Org. Chem. 2017, 13, 267–284, doi:10.3762/bjoc.13.30

• the formation of 99% of cyclized products (relative yield). The authors proposed a radical chain mechanism similar to that proposed in the reaction with Bu3SnH. While the tin radical was proposed to add to nitrogen [115], here the evidence points more to the addition of the boryl radical 76 on the

Orthogonal protection of saccharide polyols through solvent-free one-pot sequences based on regioselective silylations

• Serena Traboni,
• Emiliano Bedini and
• Alfonso Iadonisi

Beilstein J. Org. Chem. 2016, 12, 2748–2756, doi:10.3762/bjoc.12.271

• saccharide alcohols [34], the first catalytic tin-mediated procedure for regioselective benzylation/allylation of hydroxy groups incorporated into vicinal diols [35], and three alternative acetalation protocols [36]. Besides the avoided use of solvents, these approaches appear advantageous owing to their

• previously performed better than pyridine in the tin-catalyzed solvent-free regioselective benzylation or allylation of sugars [35]. The silylation rate was not appreciably influenced by tin catalysis (compare entries 2 and 3 in Table 1), although a previous report described the stoichiometric use of

• the adjacent electron-withdrawing benzoyl group. As already described above in Table 1 for mono-silylations, tin catalysis did not affect the double silylation processes as evidenced by the reaction of Table 3, entry 1 that in the presence of 0.1 equiv of Bu2SnO gave 17 in the same yield within the

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

Useful access to enantiomerically pure protected inositols from carbohydrates: the aldohexos-5-uloses route

• Felicia D’Andrea,
• Giorgio Catelani,
• Lorenzo Guazzelli and
• Venerando Pistarà

Beilstein J. Org. Chem. 2016, 12, 2343–2350, doi:10.3762/bjoc.12.227

• the absence of a coordinating metal center (for instance, in the case of tin and zirconium enolates, and of “naked” enolates generated from enolsilanes [42]). In the open-transition-state model, the enolate and the carbonyl group are orientated in an antiperiplanar fashion, maximazing the distance

High performance p-type molecular electron donors for OPV applications via alkylthiophene catenation chromophore extension

• Paul B. Geraghty,
• Calvin Lee,
• Jegadesan Subbiah,
• Wallace W. H. Wong,
• James L. Banal,
• Mohammed A. Jameel,
• Trevor A. Smith and
• David J. Jones

Beilstein J. Org. Chem. 2016, 12, 2298–2314, doi:10.3762/bjoc.12.223

• has extremely interesting properties worth further study and leads to three key questions; Synthesis: Can we simplify the synthesis of BTR removing some chromatographic purification steps and use of toxic tin containing Stille condensation reactions? Scale-up: Can we develop a multi-gram synthesis

• large scale use of tin reagents we required the key bis-borylated benzodithiophene (BDT) core 13, which was synthesised from the known BDT core 12 using iridium catalyzed borylation via CH-activation. The bis-borylated product was isolated by precipitation on addition of isopropanol (IPA), and an

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

• (Aldrich), 4-ethynyl-α,α,α-trifluorotoluene (Aldrich), n-butyllithium solution (Aldrich), tributyltin chloride (Fisher), tributyl(phenylethynyl)tin (Aldrich), tetrakis(triphenylphosphine)palladium(0) (Aldrich), n-iodosuccinimide (abbreviated NIS, Aldrich) were used as received. All other reagents and

• : calcd for C32H19F2I2N3, 736.96; found, 735.85. L1: Tributyl(phenylethynyl)tin (318 mg, 0.813 mmol) and L1-ADPI2 (200 mg, 0.271 mmol) was taken into a Schlenk flask (50 mL) which was evacuated and refilled with N2 three times. Dry chlorobenzene (15 mL) was added to the flask using a syringe and stirred

• : Tributyl(phenylethynyl)tin (0.928 g, 2.373 mmol) and L2-ADPI2 (0.500 g, 0.678 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 (0.110 g, 14

Ionic liquids as transesterification catalysts: applications for the synthesis of linear and cyclic organic carbonates

• Maurizio Selva,
• Alvise Perosa,
• Sandro Guidi and
• Lisa Cattelan

Beilstein J. Org. Chem. 2016, 12, 1911–1924, doi:10.3762/bjoc.12.181

• ionic liquid increases the catalytic activity of dibutyltin oxide fourfold probably by forming a highly active tin species where the anion of the ionic liquid acts as a ligand. The developed protocol was further studied for various substituted phenols, proving that electron-donating groups (EDG) at the

TMSBr-mediated solvent- and work-up-free synthesis of α-2-deoxyglycosides from glycals

• Mei-Yuan Hsu,
• Yi-Pei Liu,
• Sarah Lam,
• Su-Ching Lin and
• Cheng-Chung Wang

Beilstein J. Org. Chem. 2016, 12, 1758–1764, doi:10.3762/bjoc.12.164

• -deoxythioglucosides [50]. In the literature, to synthesize 2-deoxythioglycosides, a highly toxic tin hydride reagent was used to produce S-2-deoxysugars from glycosyl bromide through an anomeric glycosyl radical and acetate rearrangement, followed by subsequent thioglycosylation to afford 2-deoxythioglycosides as

Catalytic Chan–Lam coupling using a ‘tube-in-tube’ reactor to deliver molecular oxygen as an oxidant

• Carl J. Mallia,
• Paul M. Burton,
• Alexander M. R. Smith,
• Gary C. Walter and
• Ian R. Baxendale

Beilstein J. Org. Chem. 2016, 12, 1598–1607, doi:10.3762/bjoc.12.156

• proposed a catalytic mechanism and later reported a tin free aryl–amine coupling reaction [6][7]. This major breakthrough made the C–N coupling reaction accessible to a wide range of substrates, including anilines, which did not react very well with the previous conditions. However, despite the

Beta-hydroxyphosphonate ribonucleoside analogues derived from 4-substituted-1,2,3-triazoles as IMP/GMP mimics: synthesis and biological evaluation

• Tai Nguyen Van,
• Audrey Hospital,
• Corinne Lionne,
• Lars P. Jordheim,
• Charles Dumontet,
• Christian Périgaud,
• Laurent Chaloin and
• Suzanne Peyrottes

Beilstein J. Org. Chem. 2016, 12, 1476–1486, doi:10.3762/bjoc.12.144

• )-hexofuranose (2) was obtained in good yield from 1,2,5-tri-O-acetyl-3-O-benzoyl-6-deoxy-6-diethylphosphono-(α,β)-ribo-(5S)-hexofuranose [15] following a glycosylation procedure using sodium azide as nucleophilic entity and tin(IV) chloride as Lewis acid. Under these conditions, the reaction appeared highly

3,6-Carbazole vs 2,7-carbazole: A comparative study of hole-transporting polymeric materials for inorganic–organic hybrid perovskite solar cells

• Wei Li,
• Munechika Otsuka,
• Takehito Kato,
• Yang Wang,
• Takehiko Mori and
• Tsuyoshi Michinobu

Beilstein J. Org. Chem. 2016, 12, 1401–1409, doi:10.3762/bjoc.12.134

• at 25 °C in dehydrated CH3CN containing 0.1 M (n-C4H9)4NPF6 in the three electrode cell. The working, reference, and auxiliary electrodes were a glassy carbon electrode, Ag/Ag+/CH3CN/(n-C4H9)4NPF6, and a Pt wire, respectively. Fabrication and measurements of perovskite solar cells Fluorine-doped tin

Conjugate addition–enantioselective protonation reactions

• James P. Phelan and
• Jonathan A. Ellman

Beilstein J. Org. Chem. 2016, 12, 1203–1228, doi:10.3762/bjoc.12.116

• catalytic (R)-3,3’-dibromo-BINOL (16) and stoichiometric SnCl4 [19] (Scheme 4). The authors proposed that complex 18 acted as a chiral proton source to protonate a tin-enolate intermediate based upon related complexes that the Yamamoto group had previously used for the enantioselective protonation of silyl

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

• reaction was already successful with two equivalents of enolate per metal fragment. However, higher yields were obtained at higher loadings. For example, zirconium worked best with three enolate units and tin with four. Surprisingly, an excess of an enolate had different effects on the reactions depending

• radius of the B3+ ion is very small (25 pm). In the case of tin(II), a high yield of 6a (up to 90%) was observed but formation of 5a was not detected which indicates a hindrance for the second aldol addition. Presumably due to the low charge density of the Sn2+ ions the second carbonyl function is not

• sufficiently activated for the last ketone–ketone–aldol step. For lanthanum and cerium and maybe even for tin(II) the size may cause problems since these ions are too big. The distance between the reactants is probably too large for a bond formation (Table 9). In the case of 9-anthracenylaldehyde (3f

Opportunities and challenges for direct C–H functionalization of piperazines

• Zhishi Ye,
• Kristen E. Gettys and
• Mingji Dai

Beilstein J. Org. Chem. 2016, 12, 702–715, doi:10.3762/bjoc.12.70

• example, Bode and co-workers have developed a tin (Sn) amine protocol (SnAP) to synthesize piperazines and other N-heterocyles from aldehydes [12][13][14]. Aggarwal and co-workers have developed a formal [4 + 2] procotocl utilizing vinyl sulfonium salts and diamines as starting materials [15][16][17

Thermal and oxidative stability of Atlantic salmon oil (Salmo salar L.) and complexation with β-cyclodextrin

• Daniel I. Hădărugă,
• Mustafa Ünlüsayin,
• Alexandra T. Gruia,
• Cristina Birău (Mitroi),
• Gerlinde Rusu and
• Nicoleta G. Hădărugă

Beilstein J. Org. Chem. 2016, 12, 179–191, doi:10.3762/bjoc.12.20

• 8 glucopyranose units for the corresponding α-, β-, and γ-CD types [34][35]. The specific structural architecture of CDs having a hydrophilic exterior and hydrophobic inner cavity allows for tin-containing FA moieties from fish oil [36] or other hydrophobic compounds and mixtures to be more easily

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

• reported [20]. Furthermore, these results suggest that the reduction process of 3·TM-βCD displays a semi-reversible behavior. The HOMO/LUMO energy levels in combination with the electronic potentials of the anodic indium tin oxide (ITO) glass substrate (−4.75 eV) and cathodic aluminum (−2.2 eV), prove that

Fates of imine intermediates in radical cyclizations of N-sulfonylindoles and ene-sulfonamides

• Hanmo Zhang,
• E. Ben Hay,
• Stephen J. Geib and
• Dennis P. Curran

Beilstein J. Org. Chem. 2015, 11, 1649–1655, doi:10.3762/bjoc.11.181

• /fragmentation. Tin hydride-mediated cyclizations of 2-halo-N-(3-methyl-N-sulfonylindole)anilines provide spiro[indoline-3,3'-indolones] or spiro-3,3'-biindolines (derived from imine reduction), depending on the indole C2 substituent. Cyclizations of 2-haloanilide derivatives of 3-carboxy-N-sulfonyl-2,3

• is rapidly reduced by the tin hydride reagent. In contrast, cyclization of 2-ester-substituted indole 9 under the same conditions provided cyclic imine 11 even though excess tributyltin hydride (2.5 equiv) was again used. Imine 11 is a stable compound that was isolated as a clear oil in 71% yield

• 6 and 9 that the imine 14 is reduced by radical hydrostannation to give 16 via 15. Finally, protodestannylation of 16 provides isolated product 8. Imine 11 with the ester substituent on C2 is formed by a similar sequence of reactions as 14. However, tin radical addition to 11 produces a captodative

A hybrid electron donor comprising cyclopentadithiophene and dithiafulvenyl for dye-sensitized solar cells

• Gleb Sorohhov,
• Chenyi Yi,
• Michael Grätzel,
• Silvio Decurtins and
• Shi-Xia Liu

Beilstein J. Org. Chem. 2015, 11, 1052–1059, doi:10.3762/bjoc.11.118

• transparent layer and a 4 μm scattering layer of TiO2 were screen-printed on fluorine-doped tin oxide (FTO). After sintering at 500 °C for 0.5 h and cooling to room temperature, the electrodes were treated with 20 mM TiCl4 solution at 70 °C for 0.5 h. The films were sintered at 500 °C for 0.5 h and cooled to

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

• Sergey Tin Tamara Fanjul Matthew L. Clarke School of Chemistry, University of St Andrews, EaStCHEM, St Andrews, KY16 9ST, Fife, UK, FAX +44 1334 463808 Chirotech Technology Centre, Dr. Reddy’s Laboratories, Unit 410 Cambridge Science Park, Milton Road, Cambridge, CB4 0PE, UK 10.3762/bjoc.11.70