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

Phenylsilane as an effective desulfinylation reagent

• Wanda H. Midura,
• Aneta Rzewnicka and
• Jerzy A. Krysiak

Beilstein J. Org. Chem. 2017, 13, 1513–1517, doi:10.3762/bjoc.13.150

• . The desulfinylation process of compounds of this type by phenylsilane is the first observation. It is unknown until now in literature. One could assume that the active species, usually postulated in the fluoride- and base-catalyzed hydrosilylation [27][28][29][30], in the presented case is

Synthesis of oligonucleotides on a soluble support

• Harri Lönnberg

Beilstein J. Org. Chem. 2017, 13, 1368–1387, doi:10.3762/bjoc.13.134

• oligonucleotide. Since the phosphate protecting groups are normally base-labile and the repeatedly removable 5´-O protecting group is acid-labile, the 2´-O-protection should preferably be removable under orthogonal conditions. For this purpose, numerous protecting groups have been proposed [18][19], the fluoride

Detection of therapeutic radiation in three-dimensions

• John A. Adamovics

Beilstein J. Org. Chem. 2017, 13, 1325–1331, doi:10.3762/bjoc.13.129

• of the eight DTMs which varied from 4.5 times greater than LMG for the most sterically hindered bromide derivative 2 to the least for the ortho-fluoride 4 with 0.6 less dose sensitivity than LMG (Table 1). This is also consistent for the ortho-methyl derivative 5 being more dose sensitive than it’s

Total synthesis of elansolids B1 and B2

• Liang-Liang Wang and
• Andreas Kirschning

Beilstein J. Org. Chem. 2017, 13, 1280–1287, doi:10.3762/bjoc.13.124

• , 2.79 µmol, 1.0 equiv) was dissolved in THF (0.5 mL) and cooled to 0 °C. A solution of hydrogen fluoride pyridine complex (0.5 mL) prepared by mixing hydrogen fluoride pyridine (2 mL; hydrogen fluoride ≈70 %) with pyridine (5.6 mL) in THF (9.8 mL) at 0 °C. The reaction mixture was stirred for 1 h at

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

• fashion [58][59]. Therefore, they postulated that by using the correct divalent cation and suitable Lewis acid/Lewis base pairing, the necessary transition-state organization to favor glycosylation of a glycosyl fluoride would outcompete hydrolysis in the aqueous medium. This would lead to a simple non

Synthesis and enzymatic ketonization of the 5-(halo)-2-hydroxymuconates and 5-(halo)-2-hydroxy-2,4-pentadienoates

• Tyler M. M. Stack,
• William H. Johnson Jr. and
• Christian P. Whitman

Beilstein J. Org. Chem. 2017, 13, 1022–1031, doi:10.3762/bjoc.13.101

• . The implications of these findings are discussed. The availability of these compounds will facilitate future studies of the haloaromatic catabolic pathways. Keywords: dienol; enzyme kinetics; fluoride; halogen; Introduction Aromatic hydrocarbons and their halogenated derivatives are well known

• in Supporting Information File 1. The approximate percentages of the components were determined by integration and are summarized in Table 3 [15]. The highly electronegative fluoride substituent in 5d prevents the detectable formation of the corresponding α,β-unsaturated ketone, 9d. Ketonization of

Aggregation behaviour of a single-chain, phenylene-modified bolalipid and its miscibility with classical phospholipids

• Simon Drescher,
• Vasil M. Garamus,
• Christopher J. Garvey,
• Annette Meister and
• Alfred Blume

Beilstein J. Org. Chem. 2017, 13, 995–1007, doi:10.3762/bjoc.13.99

• -butylammonium fluoride (TBAF) as solvent as well as 1,4-dibromobenzene and octadec-17-yn-1-ol (Ac-C16-OH) [32][39] as starting material. Following, both triple bonds were converted into single bonds by hydrogenation. The bolalipid was finally purified by middle pressure liquid chromatography (MPLC) using CHCl3

• : tetra-n-butylammonium fluoride, TEA: triethylamine, rt: room temperature. SANS data obtained from IFT analysis for aqueous suspensions of PC-C18pPhC18-PC in D2O at different temperatures.a Supporting Information Supporting Information File 102: Experimental procedures, characterization data for

Interactions between shape-persistent macromolecules as probed by AFM

• Johanna Blass,
• Jessica Brunke,
• Franziska Emmerich,
• Cédric Przybylski,
• Vasil M. Garamus,
• Artem Feoktystov,
• Roland Bennewitz,
• Gerhard Wenz and
• Marcel Albrecht

Beilstein J. Org. Chem. 2017, 13, 938–951, doi:10.3762/bjoc.13.95

• 4 was prepared by Sonogashira reaction of 3 with trimethylsilylacetylene. Subsequent deprotection of the TMS groups using tetra-n-butylammonium fluoride and saponification of the tert-butyl ester with trifluoroacetic acid resulted in the corresponding benzoic acid 6. The latter was coupled to 6

Synthesis of ribavirin 2’-Me-C-nucleoside analogues

• Fanny Cosson,
• Aline Faroux,
• Jean-Pierre Baltaze,
• Jonathan Farjon,
• Régis Guillot,
• Jacques Uziel and
• Nadège Lubin-Germain

Beilstein J. Org. Chem. 2017, 13, 755–761, doi:10.3762/bjoc.13.74

• with tetrabutylammonium fluoride leading to the mixture of diols 17 and 18 in quantitative yield which were easily separated (Scheme 3). Finally, the aminolysis of compound 17 followed by catalytic hydrogenolysis in the presence of palladium chloride led to the desired compound 3 [22] (Scheme 4

Fluorinated cyclohexanes: Synthesis of amine building blocks of the all-cis 2,3,5,6-tetrafluorocyclohexylamine motif

• Tetiana Bykova,
• Nawaf Al-Maharik,
• Alexandra M. Z. Slawin and
• David O'Hagan

Beilstein J. Org. Chem. 2017, 13, 728–733, doi:10.3762/bjoc.13.72

• reduction on benzoic acid, quenching with methyl iodide, and then subsequent conversion of the cyclohexadiene product to a tetrafluorocycloheane motif [11]. The methyl group was a design feature to block hydrogen fluoride elimination from the position alpha to the aldehyde. The diastereoisomers of all cis

• -tetrafluorocyclohexane aldehydes 4 were used successfully in Ugi multicomponent reactions [11][12]. In this paper we report the preparation of amines of this series starting from a Birch reduction on benzonitrile, and with a similar methyl iodide quench, to generate amines 5, which are stable to hydrogen fluoride

Substitution of fluorine in M[C₆F₅BF₃] with organolithium compounds: distinctions between O- and N-nucleophiles

• Anton Yu. Shabalin,
• Nicolay Yu. Adonin and
• Vadim V. Bardin

Beilstein J. Org. Chem. 2017, 13, 703–713, doi:10.3762/bjoc.13.69

• MeOH [31] (Scheme 11). In our opinion, the reason of the negligible content of isomer [2-NuC6F4BF3]− is the lesser affinity to fluoride of Na+ and K+ compared with Li+ (considerations on the relative fluoride affinities are grounded on the crystal lattice energy of LiF (1027 kJ·mol−1), NaF (914 kJ·mol

• , the salt Li[C6F5BF3] prepared from 1-K and an excess of LiI at 22 °C in quantitative yield converted to C6F5H in high yield when being heated in DME at 55–70 °C (Scheme 12). A similar reaction of 1-K occurs in MeOH in the presence of LiCl [33]. Presumably, one role of lithium halides is the fluoride

• elimination of LiF. In contrary, the cation–anion bonds in O-nucleophiles and in N-nucleophiles are ionic (M = K, Na) and the fluoride affinities of K+ and Na+ are smaller than that of Li+. These factors determine the reaction route with K[C6F5BF3] by a simple SN2 mechanism. Preparation of

Adsorption of RNA on mineral surfaces and mineral precipitates

• Elisa Biondi,
• Yoshihiro Furukawa,
• Jun Kawai and
• Steven A. Benner

Beilstein J. Org. Chem. 2017, 13, 393–404, doi:10.3762/bjoc.13.42

• results (Table 2) that were obtained with different specimens of calcium fluoride (fluorite). Fluorites in nature are known for their dramatic and often attractive color variation, including colorless, green, yellow and purple varieties. Often, these colors are graded across a single specimen, as

Spectral and DFT studies of anion bound organic receptors: Time dependent studies and logic gate applications

• Srikala Pangannaya,
• Neethu Padinchare Purayil,
• Shweta Dabhi,
• Venu Mankad,
• Prafulla K. Jha,
• Satyam Shinde and
• Darshak R. Trivedi

Beilstein J. Org. Chem. 2017, 13, 222–238, doi:10.3762/bjoc.13.25

• ]. The leading role of anions such as fluoride, acetate and phosphate at the physiological level in promoting tooth and bone health, metabolism and genetic transduction has been well established [8][9][10][11][12][13][14]. Increasing research interest on the selective and sensitive detection of anions

• , the complete diminution of the peak at 395 nm during the successive addition of AcO− and F− ions clearly supports the deprotonation process and the requirement of 2 equiv of acetate and fluoride ions by receptor R1 to attain saturation confirms the assumed deprotonation of the OH functionality. Next

• efficient push–pull tendency existing in the host–guest interaction mechanism. The appearance of a clear isosbestic point at 500 nm clearly indicates the formation of the new complex. The complete disappearance of the absorbance at 459 nm at higher concentrations of fluoride and acetate ions is suggestive

A postsynthetically 2’-“clickable” uridine with arabino configuration and its application for fluorescent labeling and imaging of DNA

• Heidi-Kristin Walter,
• Bettina Olshausen,
• Ute Schepers and
• Hans-Achim Wagenknecht

Beilstein J. Org. Chem. 2017, 13, 127–137, doi:10.3762/bjoc.13.16

• ; found, 525.2447. Synthesis of 2. Under an Ar atmosphere 5 (0.687 g, 1.31 mmol) was dissolved in dry THF (17 mL) 1 M tetrabutylammonium fluoride in THF (3.28 mL, 3.28 mmol) was added. The reaction was stirred for 5 min at room temperature. The reaction solution was directly poured onto a short silica

Silyl-protective groups influencing the reactivity and selectivity in glycosylations

• Mikael Bols and
• Christian Marcus Pedersen

Beilstein J. Org. Chem. 2017, 13, 93–105, doi:10.3762/bjoc.13.12

• banyaside. TES-protected glycosylimidates were also employed in the synthesis of antitumor saponins which contained partially acylated oligosaccharides. The TES groups could be removed by comparatively mild treatment with fluoride without hydrolysis or migration of O-acyl groups [10]. This strategy has also

• [46][47]. This selectivity has also been demonstrated for electrophilic additions to the anomeric position. Shuto and collaborators showed that, while 2,3,4-tri-O-benzylxylopyranosyl fluoride reacted with allyltrimethylsilane and BF3 to give a mixture of α- and β-1-C-allyl xylosides, the 2,3,4-O-TBS

• -protected fluoride which is in 1C4 conformation, exclusively gave the β-xyloside. In contrast the xylosyl fluoride with a butane-2,3-bisacetal protective group, that keeps the conformation fixed in a 4C1 conformation, only gave the α-xyloside [48]. This sort of behavior fits well with the reaction model

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

• 1,2,3-triazoles [50]. After the desilylation of syn-5 using potassium fluoride in methanol (Scheme 8) the resulting mono-substituted alkyne was subjected to an established protocol using benzyl azide, copper(I) iodide, triethylamine and TBTA [51] (for a recent review see [52]). The cycloaddition

Organofluorine chemistry: Difluoromethylene motifs spaced 1,3 to each other imparts facial polarity to a cyclohexane ring

• Mathew J. Jones,
• Ricardo Callejo,
• Alexandra M. Z. Slawin,
• Michael Bühl and
• David O'Hagan

Beilstein J. Org. Chem. 2016, 12, 2823–2827, doi:10.3762/bjoc.12.281

• D) of the fluoromethane series, relative to CH3F (1.87 D) or CHF3 (1.65 D) [15][16]. Also (poly)vinylidine fluoride (~CF2CH2~) is the prototypical piezoelectric polymer, when the CF2 group are orientated (poled) in the melt [17]. The search for new and more diverse polar hydrophobic scaffolds is

Chromium(II)-catalyzed enantioselective arylation of ketones

• Gang Wang,
• Shutao Sun,
• Ying Mao,
• Zhiyu Xie and
• Lei Liu

Beilstein J. Org. Chem. 2016, 12, 2771–2775, doi:10.3762/bjoc.12.275

• enantiocontrol, while the enantioselectivity for ketone 1e bearing an electron-donating group decreased. The mild process exhibited excellent functional group tolerance, with chloride (2f), fluoride (2g), and CF3 moieties (2h) well tolerated for further manipulation [46][47]. Heteroaryl ketones such as furan

Benzothiadiazole oligoene fatty acids: fluorescent dyes with large Stokes shifts

• Lukas J. Patalag and
• Daniel B. Werz

Beilstein J. Org. Chem. 2016, 12, 2739–2747, doi:10.3762/bjoc.12.270

• membrane core with high bulkiness. BODIPY and BOIMPY scaffolds on the other hand expose fluoride residues which might be able to interact with polarized H–X bonds. Therefore, we synthesized pentaene and hexaene fatty acids which bear five or six double bonds at the terminus or in the middle of the acyl

Synthesis, dynamic NMR characterization and XRD studies of novel N,N’-substituted piperazines for bioorthogonal labeling

• Constantin Mamat,
• Marc Pretze,
• Matthew Gott and
• Martin Köckerling

Beilstein J. Org. Chem. 2016, 12, 2478–2489, doi:10.3762/bjoc.12.242

• , proteins or antibodies [34][35], mild and fast methods for radiolabeling are mandatory because of the short half-live of [18F]fluoride (t1/2: 110 min). In most cases, indirect radiolabeling is used for these more sensitive biomacromolecules due to the harsh conditions (i.e., organic solvents, high

• temperatures and basic conditions) for the direct incorporation of [18F]fluoride, which can alter the biological/pharmacological behavior or, at least, destroy sensitive biomolecules [36][37][38]. For this purpose, bioorthogonal building blocks were developed using Huisgen-click or the Staudinger ligation

• . Using these methods, a synthesis procedure for both bioorthogonal 18F-building blocks [18F]4b and [18F]5b was developed from their precursors 4a and 5a, respectively (Scheme 4). For this purpose, the nitro group of 4b and 5b was replaced by [18F]fluoride in a nucleophilic aromatic exchange reaction. To

Rearrangements of organic peroxides and related processes

• Ivan A. Yaremenko,
• Vera A. Vil’,
• Dmitry V. Demchuk and
• Alexander O. Terent’ev

Beilstein J. Org. Chem. 2016, 12, 1647–1748, doi:10.3762/bjoc.12.162

• peroxyacetal intermediate 12. Then BF3 migrates to another oxygen atom through transition state 13 to give the second Criegee intermediate 14. The decomposition of intermediate 14 finally produces 15, hydrogen fluoride (16) and ester 17. Despite the fact that the Baeyer–Villiger reaction is known since 1899

Palladium-catalyzed picolinamide-directed iodination of remote ortho-C−H bonds of arenes: Synthesis of tetrahydroquinolines

• William A. Nack,
• Xinmou Wang,
• Bo Wang,
• Gang He and
• Gong Chen

Beilstein J. Org. Chem. 2016, 12, 1243–1249, doi:10.3762/bjoc.12.119

• incompatible with directed SEAr, but was iodinated selectively at the ortho position under Pd-catalyzed conditions without the formation of regioisomeric side products. The strong para-directing effect exerted by aryl fluoride substituents overrides directed SEAr selectivity [38][39]. Thus, we observed only

Stereoselective synthesis of tricyclic compounds by intramolecular palladium-catalyzed addition of aryl iodides to carbonyl groups

• Jakub Saadi,
• Christoph Bentz,
• Kai Redies,
• Dieter Lentz,
• Reinhold Zimmer and
• Hans-Ulrich Reissig

Beilstein J. Org. Chem. 2016, 12, 1236–1242, doi:10.3762/bjoc.12.118

• aryl iodide substituent were prepared following our well-established route via 2-siloxycyclopropane carboxylates D [6][7] that allows a regioselective introduction of the benzylic substituents at the α-carbon [8][9] to give intermediates E (Scheme 2). After fluoride-promoted ring opening [10] the

• serendipitous discovery of the palladium-catalyzed cyclization to products C. Synthesis of compounds A (1–6) via methyl 2-siloxycyclopropanecarboxylates D, their alkylation to E and fluoride-induced ring opening. Palladium-catalyzed reactions of methyl ketone 1 to tetralin derivative 7 and of isopropyl

Synthesis of highly functionalized 2,2'-bipyridines by cyclocondensation of β-ketoenamides – scope and limitations

• Paul Hommes and
• Hans-Ulrich Reissig

Beilstein J. Org. Chem. 2016, 12, 1170–1177, doi:10.3762/bjoc.12.112

• -nonaflation employing nonafluorobutanesulfonyl fluoride provided the expected 4-nonafloxy-substituted bipyridine derivatives 5a–g in moderate to good overall yields. The bipyridyl nonaflates are excellent precursors for palladium-catalyzed reactions as demonstrated by representative Suzuki and Sonogashira

• using nonafluorobutanesulfonyl fluoride (NfF) as sulfonylating reagent. In subsequent publications we could demonstrate that this method can be used to synthesize a variety of functionalized pyridine derivatives, 2,2´-bipyridines or terpyridines [2][3][4]. An alternative entry to the crucial β

• of the cyclocondensation step and subjected the unpurified compounds to the O-nonaflation procedure. Treatment with an excess of sodium hydride in THF followed by reaction with nonafluorobutanesulfonyl fluoride (NfF) afforded the desired 2,2´-bipyridine derivatives 5a–g containing the 4-nonafloxy