Topochemical control of the photodimerization of aromatic compounds by γ-cyclodextrin thioethers in aqueous solution

• Hai Ming Wang and
• Gerhard Wenz

Beilstein J. Org. Chem. 2013, 9, 1858–1866, doi:10.3762/bjoc.9.217

• Hai Ming Wang Gerhard Wenz Organic Macromolecular Chemistry, Saarland University, Campus Saarbrücken C4 2, 66123 Saarbrücken, Germany 10.3762/bjoc.9.217 Abstract The formation of soluble 1:2 complexes within hydrophilic γ-cyclodextrin (γ-CD) thioethers allows to perform photodimerizations of

• aromatic guests under controlled, homogenous reaction conditions. The quantum yields for unsubstituted anthracene, acenaphthylene, and coumarin complexed in these γ-CD thioethers were found to be up to 10 times higher than in the non-complexed state. The configuration of the photoproduct reflected the

• undesirable heterogenous reaction conditions [19]. Yields of heterogenous photoreactions generally depend on the particle size of the educt phase because the penetration depth of the incident light is limited. Recently, we synthesized a series of highly water-soluble per-6-deoxy-thioethers of β- and γ-CD

Organocatalyzed enantioselective desymmetrization of aziridines and epoxides

• Ping-An Wang

Beilstein J. Org. Chem. 2013, 9, 1677–1695, doi:10.3762/bjoc.9.192

• decomposed on silica gel to form the final product. Antilla and co-workers have also shown the enantioselective desymmetrization of meso-aziridines with functionalized mercaptans in the presence of (S)-VAPOL in ether at rt to afford β-(N-acylamino)phenyl thioethers in good yields and ee’s [45]. By using 10

• mol % of commercially available chiral phosphoric acid OC-21 as a catalyst, Lattanzi [46] and colleagues have developed a facile desymmetrization of meso-N-acylaziridines with Me3SiSPh to produce β-(N-acylamino)phenyl thioethers (Scheme 5, 37 to 44) in high enantioselectivities (78–99% ee

• ). Interestingly, the aziridines with a six-membered ring were desymmetrized to give the corresponding thioethers in excellent yields and enantioselectivities when the molar ratio of aziridine/nucleophile/catalyst is 1.0:1.5:0.1. For the unreactive acyclic and seven-membered ring aziridines, the good

Space filling of β-cyclodextrin and β-cyclodextrin derivatives by volatile hydrophobic guests

• Sophie Fourmentin,
• Anca Ciobanu,
• David Landy and
• Gerhard Wenz

Beilstein J. Org. Chem. 2013, 9, 1185–1191, doi:10.3762/bjoc.9.133

• Saarbrücken, Germany 10.3762/bjoc.9.133 Abstract The inclusion of volatile derivatives of benzene and cyclohexane in β-cyclodextrin (β-CD), hydroxypropyl-β-CD, and hydrophilic β-CD-thioethers was investigated by static headspace gas chromatography (HS-GC) and molecular modelling. The obtained binding

• constants strongly increase with the amount of space filling of the CD cavity and the salt concentration. β-CD thioethers show a 3–10 times higher binding potential than native β-CD. Keywords: cyclodextrins; inclusion compound; molecular modelling; space filling; static headspace gas chromatography; vapor

• -thioethers are single pure compounds and they showed very promising binding constants and very high aqueous solubility. In continuation of our investigations into the recognition of volatile organic compounds (VOCs) by CDs [34][35], we examined the potential of these β-CD-thioethers for the solubilization of

Peptoids and polyamines going sweet: Modular synthesis of glycosylated peptoids and polyamines using click chemistry

• Daniel Fürniss,
• Timo Mack,
• Frank Hahn,
• Sidonie B. L. Vollrath,
• Katarzyna Koroniak,
• Ute Schepers and
• Stefan Bräse

Beilstein J. Org. Chem. 2013, 9, 56–63, doi:10.3762/bjoc.9.7

• attachment to other molecules through a variety of functional groups, such as amines (–NH2) and carboxylic acids (–COOH) resulting in peptide bonds, thiols (–SH) resulting in disulfides, thioethers or thioesters, aldehydes (–CHO) and hydroxy (–OH) groups. Nonetheless, coupling to these groups often requires

Stereoselective synthesis of tetrasubstituted alkenes via a sequential carbocupration and a new sulfur–lithium exchange

• Andreas Unsinn,
• Cora Dunst and
• Paul Knochel

Beilstein J. Org. Chem. 2012, 8, 2202–2206, doi:10.3762/bjoc.8.248

• thioether 4. Extensive experimentation showed that thioethers 4 do not undergo Ni- or Pd-catalyzed cross couplings leading to products of type 5 (R = Me, Ph) [15][16]. Thus, we designed a new sulfur–lithium exchange (Scheme 1). Sulfur–lithium exchanges proceed only readily with sulfoxides [17][18][19] and

• ). These quenching experiments demonstrate that this new method based on a successive carbocupration and sulfur–lithium exchange allows the stereoselective preparation of various tetrasubstituted alkenes. Since Normant has shown that various alkylcopper species add to alkynyl thioethers [38][39][40], the

The chemistry of bisallenes

• Henning Hopf and
• Georgios Markopoulos

Beilstein J. Org. Chem. 2012, 8, 1936–1998, doi:10.3762/bjoc.8.225

• in 7 (n = 1) is replaced by a heteroatom, the heteroorganic bisallenes 16 result, in their simplest form as ethers (X = O), amines (X = NR), thioethers (X = S), etc. Analogously bisallenic epoxides (17, X = O) or aziridines (17, X = NR) can formally be generated from the corresponding all-carbon

Molecular solubilization of fullerene C₆₀ in water by γ-cyclodextrin thioethers

• Hai Ming Wang and
• Gerhard Wenz

Beilstein J. Org. Chem. 2012, 8, 1644–1651, doi:10.3762/bjoc.8.188

• Hai Ming Wang Gerhard Wenz Organische Makromolekulare Chemie, Saarland University, Campus Geb. C4.2, D-66123, Saarbrücken, Germany 10.3762/bjoc.8.188 Abstract Various hydrophilic γ-cyclodextrin (CD) thioethers, containing neutral or ionic side arms were found to form molecular disperse solutions

• tendency to form nanoparticular aggregates [21][32], both of which limit their practical application. Recently, we developed a new class of highly water-soluble per-6-deoxy-thioethers of β- and γ-CD (>20% w/w), which showed exceptionally high solubilization abilities for several aromatic molecules, such as

• anthracene and acenaphthylene, in water [33][34][35]. In this work, we investigated solubilization of C60 by these γ-CD thioethers (compounds 1–7 in Scheme 1) with the hope of achieving high concentrations of solubilized C60. The hydrophilic substituents at the primary face of γ-CD should increase solubility

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

• Akademicheskii Ave., 634055 Tomsk, Russia 10.3762/bjoc.7.179 Abstract Pyrazole and benzotriazole-containing thioethers, namely 1,5-bis(3,5-dimethylpyrazol-1-yl)-3-thiapentane, 1,8-bis(3,5-dimethylpyrazol-1-yl)-3,6-dithiaoctane and 1,3-bis(1,2,3-benzotriazol-1-yl)-2-thiapropane were prepared and fully

• here was 89%, and no formation of the mercapto-derivative was detected. The properties of azole-containing thioether can be varied by functionalization of the azole ring or oxidation of the sulfur atom, and therefore we have studied the reactivity of thioethers 3–5 in electrophilic substitution and

• oxidation reactions. Oxidation of thioethers to sulfoxides and sulfones can be achieved by using different oxidants and catalysts [15], hydrogen peroxide being the most versatile and green among them [16]. Despite the simplicity of their preparation and potentially useful properties, azole-containing

Microphotochemistry: 4,4'-Dimethoxybenzophenone mediated photodecarboxylation reactions involving phthalimides

• Oksana Shvydkiv,
• Kieran Nolan and
• Michael Oelgemöller

Beilstein J. Org. Chem. 2011, 7, 1055–1063, doi:10.3762/bjoc.7.121

• . Alternatively, back electron transfer (BET) and protonation generates the simple decarboxylation products 2 and 5. Path A thus mirrors the mechanism proposed for acetone sensitization [43]. In contrast to carboxylates (for MeCO2− calc. EOx = 1.54 V in MeCN versus SCE), thioethers (for Me2S: EOx = 1.23 V versus

• SCE) are more readily oxidized [23]. As a result, electron transfer to the triplet excited DMBP becomes energetically feasible (Scheme 8, path B) [52]. Similar electron transfer scenarios have been established for photoreactions of N-methylphthalimide or benzophenone with either thioethers [54][55] or

Asymmetric synthesis of tertiary thiols and thioethers

• Jonathan Clayden and
• Paul MacLellan

Beilstein J. Org. Chem. 2011, 7, 582–595, doi:10.3762/bjoc.7.68

• , sulfimines and sulfilimines [9]. Chiral sulfoxides and sulfonium ylids have themselves been extensively used as tools for asymmetric synthesis [3]. With regard to chiral sulfur(II) compounds – namely thiols and thioethers (sulfides) with chirality at carbon – methods available for their asymmetric

• the preparation of certain families of tertiary thiols and thioethers. For example, SN2 displacement of a mesylate leaving group by thiophenol can be accomplished using α-hydroxy esters 2 (Scheme 1) [12]. The presence of the α-ester group of 3 promotes SN2 reaction in two ways: The electron

• . The use of α,α-dialkyl hydroxy esters 8 is more successful: Thioethers 10 are formed in high yield and with almost complete stereospecificity (Scheme 3). Using the same principles of low steric bulk and electronic inhibition of the SN1 reaction pathway, α-(sulfonyloxy)nitriles, easily prepared from

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

• ethylene pressure [44][45][46][47]. Most of these studies were performed with model substrates, especially propargylic derivatives such as ethers, esters, thioethers, and included both terminal and internal alkynes. When catalyst I was used, a beneficial effect of a heteroatom in propargylic position

Aromatic and heterocyclic perfluoroalkyl sulfides. Methods of preparation

• Vladimir N. Boiko

Beilstein J. Org. Chem. 2010, 6, 880–921, doi:10.3762/bjoc.6.88

• ) polyhalogenofluoro alkanes as partial fluorinated alkylating agents generates the corresponding sulfides which are appropriate precursors for subsequent conversion to perfluoroalkyl thioethers. For example, α,α-difluoro polyhalogenoalkyl sulfides and α,α-dichlorotrifluoroethyl sulfide can be obtained by reaction of

Synthesis and properties of calix[4]arene telluropodant ethers as Ag⁺ selective sensors and Ag⁺, Hg²⁺ extractants

• Yang Lu,
• Yuanyuan Li,
• Song He,
• Yan Lu,
• Changying Liu,
• Xianshun Zeng and
• Langxing Chen

Beilstein J. Org. Chem. 2009, 5, No. 59, doi:10.3762/bjoc.5.59

• greater polarizability compared to oxygen, the coordinating chemistry of heavier Group 16 analogues (S, Se, Te), especially sulfur, has attracted considerable interest in the chemical community. A number of ligands including pendant thioethers and crown thioethers with different denticity have been

Synthesis of 2-substituted 9-oxa-guanines {5-aminooxazolo[5,4-d]pyrimidin- 7(6H)-ones} and 9-oxa-2-thio- xanthines {5-mercaptooxazolo[5,4-d]pyrimidin- 7(6H)-ones}

• Subrata Mandal,
• Wen Tai Li,
• Yan Bai,
• Jon D. Robertus and
• Sean M. Kerwin

Beilstein J. Org. Chem. 2008, 4, No. 26, doi:10.3762/bjoc.4.26

• of 7a by alkylation with methyl iodide, benzyl bromide, propargyl bromide, or methyl 6-O-(tolylsulfonyl)-α-D-glucopyranoside [21] afforded the thioethers 8a–d, respectively. The structural assignment of 8a–d as thioethers rest principally on their 1H and 13C NMR spectra, which contain resonances more

• approaches to oxazolo[5,4-d]pyrimidines. Thermal cyclodehydration route to 9-oxo-guanine. Preparation of 2-substituted 5-aminooxazolo[5,4-d]pyrimidin-7(6H)-ones. Preparation of 2-substituted 5-aminooxazolo[5,4-d]pyrimidin-7(6H)-ones and related thioethers. Click chemistry elaboration of a 5-(propargylthio