Synthesis of the tetracyclic core of Illicium sesquiterpenes using an organocatalyzed asymmetric Robinson annulation

• Lynnie Trzoss,
• Jing Xu,
• Michelle H. Lacoske and
• Emmanuel A. Theodorakis

Beilstein J. Org. Chem. 2013, 9, 1135–1140, doi:10.3762/bjoc.9.126

• the C-1 center (dr = 9:1) in 81% yield (over three steps) [76]. The stereochemistry of 15 was unambiguously confirmed by single-crystal X-ray analysis of the related tosylate derivative 16 [77]. Deoxygenation of the C-15 primary alcohol was performed by: (a) mesylation of the alcohol with MsCl; and (b

Amyloid-β probes: Review of structure–activity and brain-kinetics relationships

• Todd J. Eckroat,
• Abdelrahman S. Mayhoub and
• Sylvie Garneau-Tsodikova

Beilstein J. Org. Chem. 2013, 9, 1012–1044, doi:10.3762/bjoc.9.116

• a high degree of sensitivity and selectivity in discriminating between patients with probable AD and age-matched healthy controls [28]. A pyridine analogue of 46a, florbetapir ([18F]AV-45, 46b) was also prepared using a tosylate precursor with Sumitomo modules for radiosynthesis [23][29]. Compound

• the brain, as it showed particularly slow washout rate (2.89% ID/g at 60 min). Three [18F]-labeled analogues of 56c, [18F]O-FEt-PIB (62), [18F]FBTA (63), and [18F]3'-F-PIB ([18F]GE067, 64) were also prepared. Compound 62 was synthesized by using the hydroxy group of 56c to displace the tosylate of

• installation of a trifluoroacetamide and O-demethylation gave the intermediate 118 used in a Mitsunobu reaction with 2-hydroxyethyl tosylate (119). Amine deprotection to 120 and installation of the [18F] label gave the target compound 98. Both 97 and 98 showed good affinity for Aβ1-42 aggregates (Ki = 4.5 nM

Use of 3-[¹⁸F]fluoropropanesulfonyl chloride as a prosthetic agent for the radiolabelling of amines: Investigation of precursor molecules, labelling conditions and enzymatic stability of the corresponding sulfonamides

• Reik Löser,
• Steffen Fischer,
• Achim Hiller,
• Martin Köckerling,
• Uta Funke,
• Aurélie Maisonial,
• Peter Brust and
• Jörg Steinbach

Beilstein J. Org. Chem. 2013, 9, 1002–1011, doi:10.3762/bjoc.9.115

• benzenesulfonate-based radiolabelling precursors were prepared by various routes. Comparing the reactivities of 3-thiocyanatopropyl nosylate and the corresponding tosylate towards [18F]fluoride the former proved to be superior accounting for labelling yields of up to 85%. Conditions for a reliable transformation

• -conceived and was therefore adopted for our purposes. Initially, the route described by Li et al. [18] was followed to synthesise the tosylate precursor 3 (Scheme 1). As the tosylation of the alcohol 2 proceeded in low yields and led to side products that were difficult to remove and impaired the reaction

• transformed under controlled conditions into the corresponding iodides [25]. The preparation of compound 7 can be also achieved by the transformation of alcohol 2 in an Appel-type reaction, circumventing the problems encountered during the Finkelstein reaction. Conversion of 7 with silver tosylate proceeded

Formal synthesis of (−)-agelastatin A: an iron(II)-mediated cyclization strategy

• Daisuke Shigeoka,
• Takuma Kamon and
• Takehiko Yoshimitsu

Beilstein J. Org. Chem. 2013, 9, 860–865, doi:10.3762/bjoc.9.99

• N-tosyloxycarbamate 8 and azidoformate 3 under FeBr2/Bu4NBr in EtOH conditions (see Table 1, entry 1 versus Scheme 3) likely originate from the distinct chemical property of the N–iron species (i) generated from each substrate. The possible coordination of tosylate anion to the N–iron after the N–O

Easy and direct conversion of tosylates and mesylates into nitroalkanes

• Alessandro Palmieri,
• Serena Gabrielli and
• Roberto Ballini

Beilstein J. Org. Chem. 2013, 9, 533–536, doi:10.3762/bjoc.9.58

• have now elaborated a general protocol for the direct transformation of aliphatic tosylates and mesylates into the corresponding nitro compounds. In order to optimize the reaction conditions we studied, as a test reaction, the conversion of tosylate 1a into nitropentadecane 2a (Table 1). As an initial

• technique (70 eV). IR spectra were recorded with a Perkin-Elmer Paragon 500 FTIR. General procedure for the conversion of tosylates and mesylates 1 into nitroalkanes 2. Tetrabutylammonium nitrite (TBAN, 433 mg, 1.5 mmol) was added, at room temperature, to a solution of the appropriate tosylate or mesylate 1

• , to afford the crude product 2, which was purified by flash column chromatography (heptane/ethyl acetate). Classical conversion of tosylate and mesylate into the corresponding nitroalkanes via halides. Optimization studies. Synthesis of primary nitroalkanes 2a–j. Synthesis of secondary nitroalkanes 2k

Thermotropic and lyotropic behaviour of new liquid-crystalline materials with different hydrophilic groups: synthesis and mesomorphic properties

• Alexej Bubnov,
• Miroslav Kašpar,
• Věra Hamplová,
• Ute Dawin and
• Frank Giesselmann

Beilstein J. Org. Chem. 2013, 9, 425–436, doi:10.3762/bjoc.9.45

• a yellow viscous liquid of TEG-tosylate. 1H NMR (CDCl3, 300 MHz) for the intermediate product TEG-tosylate δ (ppm) 7.72 (d, 2H, ortho to SO3), 7.30 (d, 2H, ortho to CH3), 4.10 (t, 2H, CH2OAr), 3.65–3.45 (m, 14H, CH2O), 3.30 (s, 3H, CH3O), 2.38 (s, 3H, CH3Ar). A mixture of 68 g (0.188 mol) of TEG

• –tosylate and 38 g (0.2 mol) of 4,4‘-biphenol was dissolved in 0.5 L ethanol/water (1:1) and heated under reflux. Sodium hydroxide (12 g) dissolved in 50 mL of water was added drop by drop over several hours. Boiling under reflux was continued for 4 days, the solution was then acidified with hydrochloric

Spin state switching in iron coordination compounds

• Philipp Gütlich,
• Ana B. Gaspar and
• Yann Garcia

Beilstein J. Org. Chem. 2013, 9, 342–391, doi:10.3762/bjoc.9.39

A new approach toward the total synthesis of (+)-batzellaside B

• Jolanta Wierzejska,
• Shin-ichi Motogoe,
• Yuto Makino,
• Tetsuya Sengoku,
• Masaki Takahashi and
• Hidemi Yoda

Beilstein J. Org. Chem. 2012, 8, 1831–1838, doi:10.3762/bjoc.8.210

• with TsCl in the presence of pyridine was carried out to yield the corresponding tosylate, whose activated ester group could be displaced with NaCN in DMSO to provide cyanide 15 in 80% yield over three steps [43]. Then, the N,O-acetonide group of 15 was cleaved upon treatment with p-TsOH in methanol

Two-directional synthesis as a tool for diversity-oriented synthesis: Synthesis of alkaloid scaffolds

• Kieron M. G. O’Connell,
• Monica Díaz-Gavilán,
• Warren R. J. D. Galloway and
• David R. Spring

Beilstein J. Org. Chem. 2012, 8, 850–860, doi:10.3762/bjoc.8.95

• intramolecular conjugate addition. Three of these compounds (1–3) were obtained from the corresponding alcohols [19][20] in three steps: Mitsunobu reaction with NH-Boc-tosylate, followed by tosyl deprotection with magnesium, and finally two-directional cross metathesis with ethyl acrylate to install the desired

An easy α-glycosylation methodology for the synthesis and stereochemistry of mycoplasma α-glycolipid antigens

• Yoshihiro Nishida,
• Yuko Shingu,
• Yuan Mengfei,
• Kazuo Fukuda,
• Hirofumi Dohi,
• Sachie Matsuda and
• Kazuhiro Matsuda

Beilstein J. Org. Chem. 2012, 8, 629–639, doi:10.3762/bjoc.8.70

• phosphocholine group at the sugar 6-OH position, we employed a phosphoroamidite method using 1H-tetrazole as a promoter [34]. First, 8a was treated with 2-cyanoethyl-N,N,N’,N’-tetraisopropyl phosphorodiamidite in the presence of 1H-tetrazole, and then with choline tosylate to give 9a. After removal of the sugar

• phosphorodiamidite (90.4 mg, 0.30 mmol) in 10 mL of CH2Cl2 was injected. 1H-tetrazole (28.4 mg, 0.40 mmol) was added and stirred for 2 h at rt. Then 1H-tetrazole (42.6 mg, 0.60 mmol, 3.0 equiv) and choline tosylate (220.3 mg, 0.8 mmol: thoroughly dried overnight under vacuum) were added to the reaction mixture and

• tosylate, 1H-tetrazole, (iii) mCPBA, (iv) aq. NH3 in CH3OH, (f) H2, Pd(OH)2/C in CH3OH. 1H NMR data (500 MHz) of I-a, I-b, and their precursors (9a and 9b). Acknowledgements This work was supported by the Industrial Technology Research Grant Program from New Energy and Industrial Technology Development

Reduction of benzylic alcohols and α-hydroxycarbonyl compounds by hydriodic acid in a biphasic reaction medium

• Michael Dobmeier,
• Josef M. Herrmann,
• Dieter Lenoir and
• Burkhard König

Beilstein J. Org. Chem. 2012, 8, 330–336, doi:10.3762/bjoc.8.36

• complexes [9][10][11][12][13]. Most procedures require a sequence of steps, e.g., the conversion of hydroxy groups into a chloride or bromide substituent and subsequent catalytic reduction with H2/Pt or the conversion into a tosylate and reduction with LiAlH4. The most commonly applied method is the Barton

Fifty years of oxacalix[3]arenes: A review

• Kevin Cottet,
• Paula M. Marcos and
• Peter J. Cragg

Beilstein J. Org. Chem. 2012, 8, 201–226, doi:10.3762/bjoc.8.22

Efficient, highly diastereoselective MS 4 Å-promoted one-pot, three-component synthesis of 2,6-disubstituted-4-tosyloxytetrahydropyrans via Prins cyclization

• Naseem Ahmed and
• Naveen Kumar Konduru

Beilstein J. Org. Chem. 2012, 8, 177–185, doi:10.3762/bjoc.8.19

• transfer to the hydroxy group. Then, a nucleophilic attack of PTSA resulted in α-tosyloxyether formation after losing a water molecule. In the α-tosyloxyether, the delocalization of lone-pair electrons on the oxygen atom led to the removal of the tosylate group and oxo-carbenium ion intermediate formation

• . Then, an intramolecular nucleophilic attack of the double bond in the oxo-carbenium ion led to cyclization and charge transfer complex formation with the tosylate group to afford the 2,6-disubstituted-4-tosyloxytetrahydropyran (Scheme 2). All structures of the 2,6-disubstituted-4

Synthetic approaches to multifunctional indenes

• Neus Mesquida,
• Sara López-Pérez,
• Immaculada Dinarès and
• Ermitas Alcalde

Beilstein J. Org. Chem. 2011, 7, 1739–1744, doi:10.3762/bjoc.7.204

• in which the (3-indenyl)acetic acid 7 was reduced to the corresponding alcohol 10 and transformed to tosylate 11. However, an attempt to convert the (3-indenyl)ethylsulfonate 11 into the advanced inden-5-amine 9 was ineffective, resulting in the formation of the spiro indene 12 instead, and hence

Recent advances in direct C–H arylation: Methodology, selectivity and mechanism in oxazole series

• Cécile Verrier,
• Pierrik Lassalas,
• Laure Théveau,
• Guy Quéguiner,
• François Trécourt,
• Francis Marsais and
• Christophe Hoarau

Beilstein J. Org. Chem. 2011, 7, 1584–1601, doi:10.3762/bjoc.7.187

• direct arylation of (benz)oxazoles with (pseudo)halides, carboxyarenes and organometallics Ackermann was the first to find convenient conditions for the base-assisted, Pd(0)-catalyzed direct substitutive coupling of heteroarene applicable to tosylate and mesylate electrophiles, which are prepared from

Highly efficient cyclosarin degradation mediated by a β-cyclodextrin derivative containing an oxime-derived substituent

• Michael Zengerle,
• Florian Brandhuber,
• Christian Schneider,
• Franz Worek,
• Georg Reiter and
• Stefan Kubik

Beilstein J. Org. Chem. 2011, 7, 1543–1554, doi:10.3762/bjoc.7.182

• ). Cyclodextrin derivatives tested as potential GF scavengers. General strategies used for the preparation of the investigated cyclodextrin derivatives. Reaction conditions used for the preparation of cyclodextrin derivatives 1a–e from tosylate 3. Synthesis of 3-(aminomethyl)benzaldehyde oxime (5). Reagents and

Synthesis and oxidation of some azole-containing thioethers

• Andrei S. Potapov,
• Nina P. Chernova,
• Vladimir D. Ogorodnikov,
• Tatiana V. Petrenko and
• Andrei I. Khlebnikov

Beilstein J. Org. Chem. 2011, 7, 1526–1532, doi:10.3762/bjoc.7.179

• -dimethylpyrazole and fully characterized the thioether for the first time [13]. We found that the use of freshly recrystallized Na2S·9H2O in the reaction with 1-(2-hydroxyethyl)-3,5-dimethylpyrazole tosylate (2) yields a solid product in good yield. We also prepared a pyrazole-containing thioether 4 with two

• sulfur atoms by the reaction of tosylate 2 with 1,2-ethanedithiolate formed in situ from diisothiuroium salt of 1,2-dibromoethane (Scheme 2). The proposed method of synthesis has an advantage over the previously reported one [8], since it does not involve the use of odoriferous and unstable 1,2

A new phenylethyl alkyl amide from the Ambrostoma quadriimpressum Motschulsky

• Guolei Zhao,
• Chao Yang,
• Bing Li and
• Wujiong Xia

Beilstein J. Org. Chem. 2011, 7, 1342–1346, doi:10.3762/bjoc.7.158

• -heptylidenetriphenylphosphonium bromide in the presence of n-BuLi gave adduct 11 as an (E/Z)-mixture (E/Z = 1:5) in 75% yield. Selective removal of the TBS group with pyridinium tosylate gave 12 in 98% yield [21]. With the alcohol 12 in hand, our next step was to synthesize the phosphonium salt 15 [22][23] (Scheme 4). Therefore

Recent advances in the gold-catalyzed additions to C–C multiple bonds

• He Huang,
• Yu Zhou and
• Hong Liu

Beilstein J. Org. Chem. 2011, 7, 897–936, doi:10.3762/bjoc.7.103

• the tosylate followed by the interaction with the imine and a Nazarov-like cyclization. Barluenga et al. reported a gold-catalyzed cascade reaction involving an unusual intramolecular redox process in which 5-heteroaryl-substituted ketone derivatives 372 were obtained from secondary 5-hexyn-1-ols 370

Isotopic labelling studies for a gold-catalysed skeletal rearrangement of alkynyl aziridines

• Paul W. Davies,
• Nicolas Martin and
• Neil Spencer

Beilstein J. Org. Chem. 2011, 7, 839–846, doi:10.3762/bjoc.7.96

• -disubstituted products could be achieved in quantitative yields when the counter ion was the more basic tosylate [19]. Alternatively, the use of protic, ethereal or aromatic solvents favoured the formation of the 2,5-disubstituted products regardless of the counter ion. Similar solvent regimes were employed in

Reciprocal polyhedra and the Euler relationship: cage hydrocarbons, C_nH_n and closo-boranes [B_xH_x]²⁻

• Michael J. McGlinchey and
• Henning Hopf

Beilstein J. Org. Chem. 2011, 7, 222–233, doi:10.3762/bjoc.7.30

• manipulation led to the iodo-tosylate 39 which, in the presence of base, generated the homohypostrophene, 40; [2 + 2] cycloaddition then furnished the homopentaprismanone 41. Introduction of a bridge head bromine (with the intent of carrying out a Favorskii ring contraction) proved to be impossible. Instead it

Ene–yne cross-metathesis with ruthenium carbene catalysts

• Cédric Fischmeister and
• Christian Bruneau

Beilstein J. Org. Chem. 2011, 7, 156–166, doi:10.3762/bjoc.7.22

• ][76] were prepared. One-pot EYCM followed by Brønsted acid catalyzed cyclization enabled the formation of monounsaturated cyclic amines [77]. The EYCM of homopropargylic tosylate with allylic alcohol derivatives has been used as a key step for the construction of the side chain of mycothiazole [78

Carbasugar analogues of galactofuranosides: α-O-linked derivatives

• Jens Frigell and
• Ian Cumpstey

Beilstein J. Org. Chem. 2010, 6, 1127–1131, doi:10.3762/bjoc.6.129

• were observed and were not isolated in a pure form. The free OH-2 could then be converted to its tosylate 7. Treatment of this diester 7 with sodium methoxide resulted in the direct formation of the required epoxide 4, presumably by cleavage of the C1 benzoate to the alcoholate (with retention of

• configuration) followed by intramolecular displacement of the C2 tosylate (with inversion of configuration). We synthesised the same epoxide 4 (78%) by treatment of isolated 3,5,6-tri-O-benzyl-2-O-(toluene-4-sulfonyl)-4a-carba-β-D-galactofuranose [9] with sodium hydride in DMF. We investigated ring-opening of

β-Hydroxy carbocation intermediates in solvolyses of di- and tetra-hydronaphthalene substrates

• Jaya S. Kudavalli and
• Rory A. More O'Ferrall

Beilstein J. Org. Chem. 2010, 6, 1035–1042, doi:10.3762/bjoc.6.118

• . Surprisingly, while the solvolysis of trans-2-methoxycyclohexyl tosylate has been well studied [17], there appear to have been no measurements reported for its cis isomer. We cannot compare these rate ratios directly with those for the solvolyses of cis- and trans-1-trichloroacetoxy-2

Synthesis and crystal structures of multifunctional tosylates as basis for star-shaped poly(2-ethyl-2-oxazoline)s

• Richard Hoogenboom,
• Martin W. M. Fijten,
• Guido Kickelbick and
• Ulrich S. Schubert

Beilstein J. Org. Chem. 2010, 6, 773–783, doi:10.3762/bjoc.6.96

• -oxazolines resulting in star-shaped polymers. The synthesis of the tosylates was performed by esterification of the corresponding alcohols with tosyl chloride. Recrystallization of these tosylate compounds afforded single crystals, and the X-ray crystal structures of di-, tetra- and hexa-tosylates are

• reported. The use of tetra- and hexa-tosylates, based on (di)pentaerythritol as initiators for the CROP of 2-ethyl-2-oxazoline, resulted in very slow initiation and ill-defined polymers, which is most likely caused by steric hindrance in these initiators. As a consequence, a porphyrin-cored tetra-tosylate

• initiator was prepared, which yielded a well-defined star-shaped poly(2-ethyl-2-oxazoline) by CROP as demonstrated by SEC with RI, UV and diode-array detectors, as well as by 1H NMR spectroscopy. Keywords: cationic polymerization; crystal structure; living polymerization; star-polymer; tosylate