The direct oxidative diene cyclization and related reactions in natural product synthesis

• Juliane Adrian,
• Leona J. Gross and
• Christian B. W. Stark

Beilstein J. Org. Chem. 2016, 12, 2104–2123, doi:10.3762/bjoc.12.200

• high stereoselectivity (ee >90%) to give THF diol 32. The latter could be almost quantitatively converted to the corresponding tosylate, an intermediate in Brown`s synthesis of cis-solamin A (29) [76][78], thus completing a formal synthesis of this natural product (Scheme 8). In 2006, our group

Enabling technologies and green processes in cyclodextrin chemistry

• Giancarlo Cravotto,
• Marina Caporaso,
• Laszlo Jicsinszky and
• Katia Martina

Beilstein J. Org. Chem. 2016, 12, 278–294, doi:10.3762/bjoc.12.30

• substitution of monohalogenated and monotosylated CDs (Scheme 8) . The 6I-azido-6I-deoxy-β-CD, an extremely versatile intermediate, has been obtained from the displacement of the tosylate group under MW. The reaction time was cut from several hours to 2 min (200 W max, 85 °C) and the formation of side products

• was reduced [15]. 6I-(p-Toluenesulfonyl)-β-CD was converted to 6I-formyl-β-CD via DMSO oxidation in MW with collidine in 15 min (110 W, 135 °C). MW irradiation promoted the syntheses of 6I-deoxy-6I-thio-β-CD and 6I,6IV-dideoxy-6I,6IV-dithio-β-CD via nucleophilic substitution of the primary tosylate

Synthesis of Xenia diterpenoids and related metabolites isolated from marine organisms

• Tatjana Huber,
• Lara Weisheit and
• Thomas Magauer

Beilstein J. Org. Chem. 2015, 11, 2521–2539, doi:10.3762/bjoc.11.273

• conditions [48] and an ensuing desilylation furnished a diol. In order to introduce a leaving group for the following key step, the secondary hydroxy group was tosylated to afford 79. Once again, a stereospecific Grob fragmentation of tosylate 79 served as the key step for the synthesis of the

Synthesis of D-fructose-derived spirocyclic 2-substituted-2-oxazoline ribosides

• Madhuri Vangala and
• Ganesh P. Shinde

Beilstein J. Org. Chem. 2015, 11, 2289–2296, doi:10.3762/bjoc.11.249

• benzylated using BnBr and NaH in DMF to afford 3a (Scheme 1). Further, the C6-tosyl intermediate was converted into 6-azido-6-deoxy-1,2;3,4-di-O-isopropylidene-β-D-psicofuranose (4a) by a nucleophilic displacement of the C6-O-tosylate with NaN3 in DMF at 70 °C [48]. The spectral data and the specific

Two strategies for the synthesis of the biologically important ATP analogue ApppI, at a multi-milligram scale

• Janne Weisell,
• Jouko Vepsäläinen and
• Petri A. Turhanen

Beilstein J. Org. Chem. 2015, 11, 2189–2193, doi:10.3762/bjoc.11.237

• organic addition and substitution reactions [8]. In method B, the bis(tetrabutylammonium) salt of ATP was treated with isopentenyl tosylate to produce ApppI. The crude products were purified by an ion-pair chromatographical approach, based on the method first reported by Ryu and Scott [7], using

• quadrupole time-of-flight mass spectrometer using electrospray ionization (ESI) in the positive ionization mode. The purity of the products was determined from 1H and 31P NMR spectra and was ≥95% unless stated otherwise. Procedure for the preparation of isopentenyl tosylate (7): 3-Methyl-3-buten-1-ol (770 µL

• hygroscopic solid after evaporation of appropriate fractions in vacuo. Method B: ATP bis(tetrabutylammonium) salt (187 mg, 0.189 mmol) was dissolved in dry acetonitrile (1 mL) and isopentenyl tosylate 7 (48 mg, 0.200 mmol) was added and the reaction mixture stirred for 24 h at 40 °C before the reaction

Cathodic hydrodimerization of nitroolefins

• Michael Weßling and
• Hans J. Schäfer

Beilstein J. Org. Chem. 2015, 11, 1163–1174, doi:10.3762/bjoc.11.131

• 1 the dimer 2 is obtained in 88% material yield and 90% current yield. Presumably the protons are generated at the anode by oxidation of residual water and/or the solvent DMF. A major source of residual water could be the very hygroscopic tosylate as one of the reviewers suggested. The conditions of

A procedure for the preparation and isolation of nucleoside-5’-diphosphates

• Heidi J. Korhonen,
• Hannah L. Bolt and
• David R. W. Hodgson

Beilstein J. Org. Chem. 2015, 11, 469–472, doi:10.3762/bjoc.11.52

• (triphenylphosphoranylidene)ammonium] pyrophosphate (PPN pyrophosphate) was used in the SN2 displacements of the tosylate ion from 5’-tosylnucleosides to afford nucleoside-5’-diphosphates. Selective precipitation permitted the direct isolation of nucleoside-5’-diphosphates from crude reaction mixtures. Keywords: NDP

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

• conditions. Methyl acrylate (1a) was chosen as a model substrate as it is highly reactive in standard Matsuda–Heck reactions. Therefore, a solution of 4-nitrobenzenediazonium tosylate (2a) in water was allowed to react with 1.2 equiv of methyl acrylate (1a) in the presence of 1 mol % Pd(OAc)2 at rt, at 75 °C

• (t, 2H), 3.75 (t, 2H), 2.11 (m, 2H); 13C NMR (75 MHz, DMSO-d6) δ 165.6, 142.6, 138.5, 132.7, 129.0, 121.4, 118.5, 112.3, 61.3, 41.8, 31.1; HRMS m/z: calcd. for C13H12NO2Cl, 249.0551; found, 249.0548. Arylation of methyl acrylate (1a) with arenediazonium tosylate 2a. Arylation of alkenes with ADT

• . Arylation of methyl acrylate (1a) with arenediazonium tosylate 2a. Study of reaction conditions. Arylation of alkenes with arenediazonium tosylates in water under microwave heating. Supporting Information Supporting Information File 354: Additional experimental data. Acknowledgements This research was

Photovoltaic-driven organic electrosynthesis and efforts toward more sustainable oxidation reactions

• Bichlien H. Nguyen,
• Robert J. Perkins,
• Jake A. Smith and
• Kevin D. Moeller

Beilstein J. Org. Chem. 2015, 11, 280–287, doi:10.3762/bjoc.11.32

• needed. Another point of interest is related to the choice of the electrolyte for the reaction. The reactions highlighted in Scheme 2 provide an opportunity to address this issue. Typically, the choice of electrolyte is not crucial, and tetraethylammonium tosylate can be employed for the majority of

3α,5α-Cyclocholestan-6β-yl ethers as donors of the cholesterol moiety for the electrochemical synthesis of cholesterol glycoconjugates

• Aneta M. Tomkiel,
• Adam Biedrzycki,
• Jolanta Płoszyńska,
• Dorota Naróg,
• Andrzej Sobkowiak and
• Jacek W. Morzycki

Beilstein J. Org. Chem. 2015, 11, 162–168, doi:10.3762/bjoc.11.16

• , finally, cholesteryl diphenylphosphate (5) was selected as the best cholesteryl donor [5]. Apart from these cholesterol derivatives, also simple alkyl or aryl ethers (6b–g) of 3α,5α-cyclocholestan-6β-ol (6a) (i-cholesterol) are readily available by solvolysis of cholesteryl p-tosylate in the corresponding

• cyclosteroid (i-steroid) rearrangement is a well-known steroid reaction [6]. The solvolysis of cholesteryl p-tosylate proceeds via the SN1 mechanism with the formation of a mesomerically stabilized carbocation. The addition of a nucleophile (alcohol, water, etc.) may occur either to C-3 or C-6, depending on

• –h was prepared including alkyl, aryl, and silyl ethers. Most of the compounds were prepared by solvolysis of cholesteryl p-tosylate in an appropriate alcohol (neat or mixed with dioxane) in the presence of potassium acetate as a buffer. TBDMS ether 6h was obtained by silylation of i-cholesterol 6a

Conjugates of methylated cyclodextrin derivatives and hydroxyethyl starch (HES): Synthesis, cytotoxicity and inclusion of anaesthetic actives

• Lisa Markenstein,
• Antje Appelt-Menzel,
• Marco Metzger and
• Gerhard Wenz

Beilstein J. Org. Chem. 2014, 10, 3087–3096, doi:10.3762/bjoc.10.325

• -O-tosylate to β-CD-N3 following the procedures of Hocquelet et al. who also described the permethylated β-CD-N3 [39]. Furthermore, we headed for the regioselective 2,6-dimethylated product. Therefore β-CD-N3 was carefully methylated by dimethyl sulfate and a mixture of Ba(OH)2·8H2O and BaO as the

First chemoenzymatic stereodivergent synthesis of both enantiomers of promethazine and ethopropazine

• Paweł Borowiecki,
• Daniel Paprocki and
• Maciej Dranka

Beilstein J. Org. Chem. 2014, 10, 3038–3055, doi:10.3762/bjoc.10.322

• disappointment, none of these attempts led to success. When Mitsunobu chemistry fails, a hydroxy group inversion by tosylation and displacement using amine was performed. Unfortunately, attempts to carry out the reaction at higher temperature led to complete decomposition of the tosylate substrate. In the

Synthetic strategies for the fluorescent labeling of epichlorohydrin-branched cyclodextrin polymers

• Milo Malanga,
• Mihály Bálint,
• István Puskás,
• Kata Tuza,
• Tamás Sohajda,
• László Jicsinszky,
• Lajos Szente and
• Éva Fenyvesi

Beilstein J. Org. Chem. 2014, 10, 3007–3018, doi:10.3762/bjoc.10.319

• the product as shown in Supporting Information File 1, Figure S16. The tosyl-related impurities (tosic acid/tosylate) were determined by CE and the level of the impurities resulted below 0.02% w/w. The introduction of tosyl groups into the methylated polymeric network only slightly modifies the

Gold(I)-catalysed synthesis of a furan analogue of thiamine pyrophosphate

• Amjid Iqbal,
• El-Habib Sahraoui and
• Finian J. Leeper

Beilstein J. Org. Chem. 2014, 10, 2580–2585, doi:10.3762/bjoc.10.270

• MnO2, condensation with 3-anilinopropionitrile, and then reaction with acetamidine gives the thiamine analogue 15. Tosylation of the alcohol and displacement of tosylate by the diphosphate trianion worked well to give ThDP analogue 17. A further objective was to show that the furan ring could be

Derivatives of the triaminoguanidinium ion, 3. Multiple N-functionalization of the triaminoguanidinium ion with isocyanates and isothiocyanates

• Jan Szabo,
• Kerstin Karger,
• Nicolas Bucher and
• Gerhard Maas

Beilstein J. Org. Chem. 2014, 10, 2255–2262, doi:10.3762/bjoc.10.234

• occurred, leading to the corresponding tosylate 5-OTs instead of the chloride. Hydrochloric acid can also be used as an activator. However, the corresponding chloride salt 5-Cl was not obtained in an analytically pure form, which is why we continued to work with the tosylate. Since we used racemic

Facile synthesis of 1-alkoxy-1H-benzo- and 7-azabenzotriazoles from peptide coupling agents, mechanistic studies, and synthetic applications

• Mahesh K. Lakshman,
• Manish K. Singh,
• Mukesh Kumar,
• Raghu Ram Chamala,
• Vijayender R. Yedulla,
• Domenick Wagner,
• Evan Leung,
• Lijia Yang,
• Asha Matin and
• Sadia Ahmad

Beilstein J. Org. Chem. 2014, 10, 1919–1932, doi:10.3762/bjoc.10.200

• , and other chemical experiments, phosphonium and tosylate derivatives of alcohols seem to be intermediates. These then react with BtO− and AtO− produced in situ. In order to demonstrate broader utility, this novel reaction has been used to prepare a series of acyclic nucleoside-like compounds. Because

• -OTs). Furthermore, we have used Bt-OTs for conversion of aldoximes to nitriles and this reagent was generally comparable to BOP in those reactions. This factor additionally favored the selection of these two tosylate derivatives. As can be seen from Table 2, Bt-OTs is superior to BOP, and a wide range

• this problem encountered with 4-nitrobenzyl alcohol. However, use of slightly modified conditions resulted in the formation of the desired product 1o in good yield (see Supporting Information File 1 for details). Reaction of phenol with Bt-OTs resulted in the formation of the phenyl tosylate (Table 2

A complete series of 6-deoxy-monosubstituted tetraalkylammonium derivatives of α-, β-, and γ-cyclodextrin with 1, 2, and 3 permanent positive charges

• Martin Popr,
• Simona Hybelbauerová and
• Jindřich Jindřich

Beilstein J. Org. Chem. 2014, 10, 1390–1396, doi:10.3762/bjoc.10.142

• mixture of monosubstituted product 6I-O-p-toluenesulfonyl-β-cyclodextrin (1), unreacted β-CD, and some highly-substituted derivatives, which needed to be separated in order to receive pure tosylate 1. This fact is omitted in the original paper [17]. We used a strategy based on the repeated crystallization

• the preparation of 24 involved a 4-step protocol. In the first step, one hydroxy group of ethylene glycol was substituted by tosylate to yield 92% of 2-hydroxyethyl-4-methylbenzenesulfonate (21). Next, compound 22 was prepared by a nucleophilic substitution with sodium azide. The product of this

An economical and safe procedure to synthesize 2-hydroxy-4-pentynoic acid: A precursor towards ‘clickable’ biodegradable polylactide

• Quanxuan Zhang,
• Hong Ren and
• Gregory L. Baker

Beilstein J. Org. Chem. 2014, 10, 1365–1371, doi:10.3762/bjoc.10.139

• synthetic route to prepare 1 using cheap and commercially available diethyl 2-acetamidomalonate (4) and propargyl alcohol. The desired product 1 was obtained via alkylation of malonate 4 with propargyl tosylate followed by a one-pot four-step sequence of hydrolysis, decarboxylation, diazotization and

• hydroxylation of propargylic malonate 5 without work-up of any intermediate. Keywords: alkylation; ‘click’ chemistry; ‘clickable’ polylactide; decomposition; diethyl 2-acetamidomalonate; 2-hydroxy-4-pentynoic acid; one-pot; optimization; propargyl bromide; propargyl tosylate; safe and economical; Introduction

• source of acetylene building moiety; and 2) basic reaction conditions involving a low pKa (<24) to avoid the interruption of the ethynyl proton (pKa ~24) while introducing the acetylene moiety. Propargyl tosylate, prepared from propargyl alcohol and tosyl chloride, is a safe analogue of propargyl bromide

4-Hydroxy-6-alkyl-2-pyrones as nucleophilic coupling partners in Mitsunobu reactions and oxa-Michael additions

• Michael J. Burns,
• Thomas O. Ronson,
• Richard J. K. Taylor and
• Ian J. S. Fairlamb

Beilstein J. Org. Chem. 2014, 10, 1159–1165, doi:10.3762/bjoc.10.116

• , entry 2), a tosylate leaving group (Table 1, entry 4), and a halide (Table 1, entry 5). Somewhat more exotic functional groups such as a phosphonate ester (Table 1, entry 6) or a dimethyl acetal (Table 1, entry 7) were still tolerated in the reaction, albeit in more modest yields. A variety of alkylated

Preparation of phosphines through C–P bond formation

• Iris Wauters,
• Wouter Debrouwer and
• Christian V. Stevens

Beilstein J. Org. Chem. 2014, 10, 1064–1096, doi:10.3762/bjoc.10.106

• temperature when the vinyl tosylate was substituted with an electron-withdrawing group like in 85 (Scheme 22). The group of Gaumont has also reported their preliminary results for the enantioselective palladium-catalyzed C–P cross-coupling reaction between an achiral vinyl triflate 80c and a racemic secondary

Structure elucidation of female-specific volatiles released by the parasitoid wasp Trichogramma turkestanica (Hymenoptera: Trichogrammatidae)

• Armin Tröger,
• Teris A. van Beek,
• Martinus E. Huigens,
• Isabel M. M. S. Silva,
• Maarten A. Posthumus and
• Wittko Francke

Beilstein J. Org. Chem. 2014, 10, 767–773, doi:10.3762/bjoc.10.72

• ether 3 and subsequently to the corresponding tosylate 4. Using 3-methylbutylmagnesium bromide and applying cuprate chemistry [14], 4 was chain elongated to 5, which was deprotected to yield anti-2,4,8-trimethylnonanol (6). After oxidation to the corresponding aldehyde, the stereogenic center at

Polyglycerol-functionalized nanodiamond as a platform for gene delivery: Derivatization, characterization, and hybridization with DNA

• Li Zhao,
• Yuki Nakae,
• Hongmei Qin,
• Tadamasa Ito,
• Takahide Kimura,
• Hideto Kojima,
• Lawrence Chan and
• Naoki Komatsu

Beilstein J. Org. Chem. 2014, 10, 707–713, doi:10.3762/bjoc.10.64

• (tosylate) → –N3) in the PG layer, and click conjugation of the basic polypeptides (Arg8, Lys8 or His8) terminated with propargyl glycine. The ND-PG-BPP exhibited good dispersibility in water (>1.0 mg/mL) and positive zeta potential ranging from +14.2 mV to +44.1 mV at neutral pH in Milli-Q water. It was

Recent applications of the divinylcyclopropane–cycloheptadiene rearrangement in organic synthesis

• Sebastian Krüger and
• Tanja Gaich

Beilstein J. Org. Chem. 2014, 10, 163–193, doi:10.3762/bjoc.10.14

• -protected alcohol 152. Addition of methyllithium at low temperature [133] resulted in stereoselective conjugate attachment of the required methyl group. Deprotection of the alcohol and transformation into a suitable leaving group yielded tosylate 153. Next, the furan was cleaved oxidatively, the resulting

Silica: An efficient catalyst for one-pot regioselective synthesis of dithioethers

• Samir Kundu,
• Babli Roy and
• Basudeb Basu

Beilstein J. Org. Chem. 2014, 10, 26–33, doi:10.3762/bjoc.10.5

• showed varying results under conditions A or B, and allyl acetate did not undergo any desired reaction, but merely produced the disulfide from oxidative dimerization of the thiol (Table 1, entries 6–8). Allyl tosylate, however, produced the desired thioethers in a regioselective manner, but with

Consecutive cross-coupling reactions of 2,2-difluoro-1-iodoethenyl tosylate with boronic acids: efficient synthesis of 1,1-diaryl-2,2-difluoroethenes

• Ju Hee Kim,
• Su Jeong Choi and
• In Howa Jeong

Beilstein J. Org. Chem. 2013, 9, 2470–2475, doi:10.3762/bjoc.9.286

• Ju Hee Kim Su Jeong Choi In Howa Jeong Department of Chemistry & Medical Chemistry, Yonsei University, 1 Yonseidae-gil, Wonju, Gangwondo 220-710, Republic of Korea 10.3762/bjoc.9.286 Abstract The cross-coupling reactions of 2,2-difluoro-1-iodoethenyl tosylate (2) with 2 equiv of boronic acids in

• -difluoro-1-iodoethenyl tosylate; organo-fluorine; Introduction The synthesis of 2,2-disubstituted-1,1-difluoroethenes have received much attention to synthetic organofluorine chemists in recent years because of their unique chemical reactivities toward nucleophiles to produce monofluorinated organic

• bearing a metal functional group, a halogen substituent or a tosylate group at the vinyl carbon will provide a concise and efficient method for the synthesis of 2,2-disubstituted-1,1-difluoroethenes. Burton et al. reported a straightforward method for the preparation of 1,1-diaryl-2,2-difluoroethenes from