Sequential Diels–Alder/[3,3]-sigmatropic rearrangement reactions of β-nitrostyrene with 3-methyl-1,3-pentadiene

• Peter A. Wade,
• Alma Pipic,
• Matthias Zeller and
• Panagiota Tsetsakos

Beilstein J. Org. Chem. 2013, 9, 2137–2146, doi:10.3762/bjoc.9.251

• . Nitronic ester 26c with a sulfone group (Hammett σp 0.68) [20] at the C(I) position rearranges at 80 °C to 28b whereas analogous nitronic ester 26d with phenacyl group, a less powerful W-group (Hammett σp 0.43) [20], requires 120 °C for rearrangement to 28c [2]. The [3,3]-sigmatropic rearrangement of 26a

• similar bicyclic transition state must be involved [2]. The high reactivity of nitronic ester 30 is presumably due to the combined presence of a C(I) sulfone group and a C(IV) methyl group. In particular, the presence of an electron-attracting substituent at C(I) appears to have a greater accelerative

The chemistry of isoindole natural products

• Klaus Speck and
• Thomas Magauer

Beilstein J. Org. Chem. 2013, 9, 2048–2078, doi:10.3762/bjoc.9.243

• (52) and cytochalasin L-696,474 (78) diverged. For 78, another five steps were necessary to form the isoindolinone 74. After oxidation of the primary alcohol with Dess–Martin periodinane, the obtained aldehyde was coupled with the readily available N-phenyltetrazole sulfone 75 via a Julia–Kocienski

Stereoselective synthesis of the C79–C97 fragment of symbiodinolide

• Hiroyoshi Takamura,
• Takayuki Fujiwara,
• Isao Kadota and
• Daisuke Uemura

Beilstein J. Org. Chem. 2013, 9, 1931–1935, doi:10.3762/bjoc.9.228

• Julia–Kocienski olefination as the coupling reaction. The new retrosynthetic analysis of the C79–C97 fragment 8 is described in Scheme 2. We envisaged that the diol 8 could be synthesized by the Julia–Kocienski olefination [12][13][14] between aldehyde 9 and 1-phenyl-1H-tetrazol-5-yl (PT)-sulfone 10 and

• /Mo(VI) [23] to yield PT-sulfone 23. The TBDPS protecting group of 23 was transformed to the TBS group in two steps to provide PT-sulfone 24. With the coupling precursors aldehyde 20 and PT-sulfones 23 and 24 in hand, we next examined the Julia–Kocienski olefination [12][13][14] of these compounds

• (Table 1). Deprotonation of the PT-sulfone 23 with KHMDS, followed by addition of the aldehyde 20, gave rise to the desired coupling product (E)-25 along with (Z)-25 in 27% combined yield at a 3.5:1 diastereomeric ratio (Table 1, entry 1). When NaHMDS was used as the base, the chemical yield was improved

Ethyl diazoacetate synthesis in flow

• Mariëlle M. E. Delville,
• Jan C. M. van Hest and
• Floris P. J. T. Rutjes

Beilstein J. Org. Chem. 2013, 9, 1813–1818, doi:10.3762/bjoc.9.211

• elimination of the sulfone substituent. Additionally, Ley et al. [19] recently prepared a range of α-hydroxy acids in flow starting from the corresponding amino acids, involving diazotization of the amine to the diazonium salt in a biphasic system. Inspired by Ley’s approach, which is significantly more atom

Dipolar addition to cyclic vinyl sulfones leading to dual conformation tricycles

• Steven S. Y. Wong,
• Michael G. Brant,
• Christopher Barr,
• Allen G. Oliver and
• Jeremy E. Wulff

Beilstein J. Org. Chem. 2013, 9, 1419–1425, doi:10.3762/bjoc.9.159

• coupling partners for these cycloadditions, and in many cases the reaction rate can be enhanced through the addition of a Lewis acid that can coordinate to the carbonyl function, thereby lowering the energy of the olefin LUMO. By contrast, vinyl sulfones (with the exception of simple aryl vinyl sulfone

• species [13][14][15][16][17][18][19][20][21]) have been less-frequently employed as acceptors in 1,3-dipolar cycloadditions [22][23][24][25]. Indeed, we are only aware of a single prior example of a cyclic alkyl vinyl sulfone participating in a dipolar addition with an azomethine ylide [26]. In part, this

• lack of reactivity is due to a poor orbital overlap between the sulfone and olefin functions [27][28][29]; while vinyl sulfones are electrophilic (due to the inductive effects of the sulfone group), their LUMO cannot be as easily perturbed by the addition of a Lewis acid. We previously described the

Homolytic substitution at phosphorus for C–P bond formation in organic synthesis

• Hideki Yorimitsu

Beilstein J. Org. Chem. 2013, 9, 1269–1277, doi:10.3762/bjoc.9.143

• the regioselectivity, these addition reactions naturally involve C–P bond formation by homolytic substitution at phosphorus (Scheme 5). Studer recently reported similar silylphosphination of phenyl vinyl sulfone with Me3Si–PPh2 [26]. Tzschach reported that tetraorganodiphosphines R2P–PR2 add to

• Me3M–PPh2 (M = Sn, Si) and V-40 (Table 9) [26]. Secondary and tertiary alkyl iodides participate in the addition reaction while primary alkyl iodide results in direct phosphination prior to the expected addition. Not only acrylate ester but also acrylamide, vinyl sulfone, and acrylonitrile are good

Appel-reagent-mediated transformation of glycosyl hemiacetal derivatives into thioglycosides and glycosyl thiols

• Tamashree Ghosh,
• Abhishek Santra and
• Anup Kumar Misra

Beilstein J. Org. Chem. 2013, 9, 974–982, doi:10.3762/bjoc.9.112

• ][2][3][4][5]. Due to their thermal and chemical stability, they have been used as stable intermediates for functional-group transformations as well as stereoselective glycosylations. Thioglycosides can be transformed into various other glycosyl donors [6][7][8][9][10] (e.g., sulfoxide, sulfone

Some aspects of radical chemistry in the assembly of complex molecular architectures

• Béatrice Quiclet-Sire and
• Samir Z. Zard

Beilstein J. Org. Chem. 2013, 9, 557–576, doi:10.3762/bjoc.9.61

• addition to phenyl vinyl sulfone and closure to form the cyclopentane ring in 19, and then by a second intermolecular addition to phenyl vinyl sulfone to furnish radical 20, which finally evolves into the observed product 21 by transfer of the pyridylthiyl group from the starting Barton ester 16. Even

• carboxylic acid derivative 23 [18]. As in the previous sequence, radical 24, generated following the second addition to the vinyl sulfone, is electrophilic in character and does not add further; it simply propagates the chain by reacting with the starting thiohydroxamate 23. The complex bicyclic structure 25

• , exposure of bis-sulfone 25 to trimethylaluminium causes the regioselective replacement of the terminal sulfone with a methyl group to give compound 26 in good yield. The Barton decarboxylation reaction is an exceptionally powerful method that deserves without doubt a much greater attention from synthetic

Recent advances in transition-metal-catalyzed intermolecular carbomagnesiation and carbozincation

• Kei Murakami and
• Hideki Yorimitsu

Beilstein J. Org. Chem. 2013, 9, 278–302, doi:10.3762/bjoc.9.34

• -substituted alkynes, such as alkynyl sulfones, sulfoxides, or sulfoximines as electron-deficient alkynes. Xie reported a copper-catalyzed carbomagnesiation of alkynyl sulfone to give the corresponding alkenylmagnesium intermediates (Scheme 2) [39][40]. Interestingly, the stereochemistry of the products was

• allylmagnesiation of alkynyl sulfone. Copper-catalyzed four-component reaction of alkynyl sulfoxide with alkylzinc reagent, diiodomethane, and benzaldehyde. Rhodium-catalyzed reaction of aryl alkynyl ketones with arylzinc reagents. Allylmagnesiation of propargyl alcohol, which provides the anti-addition product

The chemistry of bisallenes

• Henning Hopf and
• Georgios Markopoulos

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

Organocatalytic cascade aza-Michael/hemiacetal reaction between disubstituted hydrazines and α,β-unsaturated aldehydes: Highly diastereo- and enantioselective synthesis of pyrazolidine derivatives

• Zhi-Cong Geng,
• Jian Chen,
• Ning Li,
• Xiao-Fei Huang,
• Yong Zhang,
• Ya-Wen Zhang and
• Xing-Wang Wang

Beilstein J. Org. Chem. 2012, 8, 1710–1720, doi:10.3762/bjoc.8.195

• screening results are summarized in Table 3. (S)-Proline derivatives 1g–h, 1k, 1l were found to be ineffective for the reaction, because they afford only trace products after one day (Table 3, entries 1, 2, 5 and 6). Although a moderate yield was obtained with organocatalyst 1i bearing a sulfone functional

Synthesis of compounds related to the anti-migraine drug eletriptan hydrobromide

• Suri Babu Madasu,
• Nagaji Ambabhai Vekariya,
• M. N. V. D. Hari Kiran,
• Badarinadh Gupta,
• Aminul Islam,
• Paul S. Douglas and
• Korupolu Raghu Babu

Beilstein J. Org. Chem. 2012, 8, 1400–1405, doi:10.3762/bjoc.8.162

• -3-(N-methylpyrrolidin-2-ylmethyl)-1H-indole (9) by using acetic anhydride and triethylamine in N,N-dimethylformamide affords (R)-1-acetyl-5-bromo-3-(N-methylpyrrolidin-2-ylmethyl)-1H-indole (10). When coupled in situ with phenyl vinyl sulfone (11) in the presence of a catalytic amount of palladium

Parallel and four-step synthesis of natural-product-inspired scaffolds through modular assembly and divergent cyclization

• Hiroki Oguri,
• Haruki Mizoguchi,
• Hideaki Oikawa,
• Aki Ishiyama,
• Masato Iwatsuki,
• Kazuhiko Otoguro and
• Satoshi Ōmura

Beilstein J. Org. Chem. 2012, 8, 930–940, doi:10.3762/bjoc.8.105

• cytotoxic activities. Incorporation of dimethyl substituents on the scaffold resulted in diminished activity (41b: IC50 = 5.89 μg/mL) (Table 1, entry 3). Removal of the nosyl group (39b→39c) also caused substantial loss of the activities, suggesting the critical role of the aromatic sulfone amide moiety

Synthesis and characterization of a novel carboxyl group containing (co)polyimide with sulfur in the polymer backbone

• Miroslav Mrsevic,
• David Düsselberg and
• Claudia Staudt

Beilstein J. Org. Chem. 2012, 8, 776–786, doi:10.3762/bjoc.8.88

• previous work of our group showed that the imidization degree of chemically converted PAAs is superior to thermally imidized PAAs [24]. Aromatic diamines as shown in Scheme 1, carrying either sulfone (3,3′-diaminodiphenyl sulfone, 3,3′-DDS), or (as partly described in a previous work from our group

• ). Similar results were found for the sulfone-containing 6FDA-3,3′-DDS/6FDA-DABA 4:1, which is shown in Figure 4. All synthesized (co)polyimides showed the expected vibrational bands. GPC measurements Gel permeation chromatography (GPC) measurements of the synthesized (co)polyimides were performed in order

• -mentioned behavior. Apparently, the sulfide-containing (co)polyimides exhibit higher Tg values than the sulfone-containing (co)polyimides. This is due to the differently substituted aromatic diamines. The para-substituted 4,4′-SDA induces a higher stiffness compared to the meta-substituted 3,3′-DDS, which

Derivatives of phenyl tribromomethyl sulfone as novel compounds with potential pesticidal activity

• Krzysztof M. Borys,
• Maciej D. Korzyński and
• Zbigniew Ochal

Beilstein J. Org. Chem. 2012, 8, 259–265, doi:10.3762/bjoc.8.27

• tribromomethyl phenyl sulfone derivatives as novel potential pesticides is reported. The title sulfone was obtained by following three different synthetic routes, starting from 4-chlorothiophenol or 4-halogenphenyl methyl sulfone. Products of its subsequent nitration were subjected to the SNAr reactions with

• . Keywords: 2-nitroaniline derivatives; phenylhydrazones; pesticides; SNAr reaction; tribromomethyl sulfone derivatives; Introduction The rapid growth of the world population results in a continous increase in the demand for food. At the same time, about 35% of the global crops around the world are being

• containing a tribromomethylsulfonyl group, including derivatives of nitroaniline, nitrophenylhydrazine, diphenyl ether and benzimidazole (Scheme 1). All the target molecules are derived from a common precursor, namely 4-halogenphenyl tribromomethyl sulfone, efficiently synthesized from inexpensive 4

Improved syntheses of high hole mobility phthalocyanines: A case of steric assistance in the cyclo-oligomerisation of phthalonitriles

• Daniel J. Tate,
• Rémi Anémian,
• Richard J. Bushby,
• Suwat Nanan,
• Stuart L. Warriner and
• and Benjamin J. Whitaker

Beilstein J. Org. Chem. 2012, 8, 120–128, doi:10.3762/bjoc.8.14

• bis-alkylation of thiophene (1), oxidation to the corresponding sulfone 3, and treatment with fumaronitrile (Scheme 1, top line). However, for most of the phthalonitriles we have made, we have found that a much better route is the nickel-catalysed reaction of an alkylzinc iodide with the bistriflate

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

• characterized. Oxidation of the pyrazole-containing thioether by hydrogen peroxide proceeds selectively to provide a sulfoxide or sulfone, depending on the amount of oxidant used. Oxidation of the benzotriazole derivative by hydrogen peroxide is not selective, and sulfoxide and sulfone form concurrently

• . Selenium dioxide-catalyzed oxidation of benzotriazole thioether by H2O2, however, proceeds selectively and yields sulfoxide only. Keywords: azole; oxidation; sulfone; sulfoxide; thioether; Introduction Compounds comprising two pyrazole moieties linked by an aliphatic spacer act as bidentate chelating

• through its conversion to sulfoxide or sulfone derivatives. In this report we present the synthesis of pyrazole and benzotriazole thioether ligands and their oxidation to the corresponding sulfoxides and sulfones. Results and Discussion 1-(2-Hydroxyethyl)-3,5-dimethylpyrazole (1), the starting compound

Rh(I)-catalyzed intramolecular [2 + 2 + 1] cycloaddition of allenenes: Construction of bicyclo[4.3.0]nonenones with an angular methyl group and tricyclo[6.4.0.0^1,5]dodecenone

• Fuyuhiko Inagaki,
• Naoya Itoh,
• Yujiro Hayashi,
• Yumi Matsui and
• Chisato Mukai

Beilstein J. Org. Chem. 2011, 7, 404–409, doi:10.3762/bjoc.7.52

• proximal double bond of the allene might be mandatory. Removal of the allylic sulfone group in 2a was achieved by tributyltin hydride in the presence of AIBN to give 9g in 91% yield [35][36][37][38][39][40][41]. Thus, the phenylsulfonyl group of 2a can be regarded as a hydrogen surrogate and this procedure

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

Synthesis, characterization and photoinduced curing of polysulfones with (meth)acrylate functionalities

• Cemil Dizman,
• Sahin Ates,
• Lokman Torun and
• Yusuf Yagci

Beilstein J. Org. Chem. 2010, 6, No. 56, doi:10.3762/bjoc.6.56

• bands for the polyether sulfone backbone. The new broad but weak peak around 3435 cm−1 indicates the presence of phenolic end groups. Attachment of polymerizable acrylate and methylacrylate functional groups through the esterification process was evidenced by the disappearance of this peak and the

• appears in all the spectra at 1.69 ppm. The shifts between 6.70 and 7.86 ppm correspond to the aromatic protons of the poly(ether sulfone) backbone. The phenolic protons were not observed, probably due to the relatively high molecular weight of the precursor polymers. Distinctively, the aromatic protons

• important components of UV curable formulations for obtaining networks that could have application in coatings and membranes. Experimental Materials Bisphenol A and bis(p-chlorophenyl) sulfone (Hallochem Pharma Co. Ltd, China), methanol (Merck), dimethylacetamide (DMA, 99%, Merck) were used without any

Mitomycins syntheses: a recent update

• Jean-Christophe Andrez

Beilstein J. Org. Chem. 2009, 5, No. 33, doi:10.3762/bjoc.5.33

Reduction of arenediazonium salts by tetrakis(dimethylamino)ethylene (TDAE): Efficient formation of products derived from aryl radicals

• Mohan Mahesh,
• John A. Murphy,
• Franck LeStrat and
• Hans Peter Wessel

Beilstein J. Org. Chem. 2009, 5, No. 1, doi:10.3762/bjoc.5.1

• like a sulfide, sulfoxide or sulfone is necessary for the self-termination of the 5-exo-trig radical cyclization reactions to avoid competing intermolecular radical side-reactions. The TDAE-mediated radical-based addition-elimination route for the construction of indole ring systems warranted anhydrous

Recent progress on the total synthesis of acetogenins from Annonaceae

• Nianguang Li,
• Zhihao Shi,
• Yuping Tang,
• Jianwei Chen and
• Xiang Li

Beilstein J. Org. Chem. 2008, 4, No. 48, doi:10.3762/bjoc.4.48

• intermediate 31; further manipulation and chain elongation at both ends of 31 produced an advanced intermediate 32. The anion of the phenyl sulfone 33, readily prepared from D-glutamic acid, was condensed directly with the ester function of 32 to give the α-keto sulfone 34, which was futher elaborated to ester

Radical cascades using enantioenriched 7-azabenzonorbornenes and their applications in synthesis

• David M. Hodgson and
• Leonard H. Winning

Beilstein J. Org. Chem. 2008, 4, No. 38, doi:10.3762/bjoc.4.38

• -observed trend that alkenes bearing less strongly electron-withdrawing substituents were less effective electrophiles in this reaction. Phenyl vinyl sulfone gave trapped rearranged azacycle 13 in 43% yield, with rearranged–reduced azacycle 8 also isolated in 38% yield, suggesting that the rate of

• electrophile trapping with the sulfone corresponds approximately to the rate of hydrogen atom transfer from (TMS)3SiH. Attempted reaction with methyl vinyl ketone, N,N-dimethylacrylamide and methyl propiolate gave rearranged-reduced azacycle 8 in modest yields, as well as small quantities of hydrosilylated

• electrophile (for details see Supporting Information File 1) [26]. Having probed the generality of the reaction, attempts were made to optimise the yields of the electrophile trapping. These studies were performed with phenyl vinyl sulfone, since this had undergone partial electrophile trapping and partial

The role of an aromatic group in remote chiral induction during conjugate addition of α-sulfonylallylic carbanions to ethyl crotonate

• Shlomo Levinger,
• Ranjeet Nair and
• Alfred Hassner

Beilstein J. Org. Chem. 2008, 4, No. 32, doi:10.3762/bjoc.4.32

• -substituted allyl sulfone 1, containing a stereogenic center, proceeded with diastereoselectivity of greater than 8:2 (ratio of 3 to 4), when the Ar substituent in 1 was phenyl or 1-naphthyl (Scheme 1). On the other hand, when this substituent (Ar in Scheme 1) was cyclohexyl, no selectivity at all was

• observed (dr 1:1). We had proposed that π–Li+ interaction may be responsible for this phenomenon. We had shown earlier [2] that conjugate addition of lithiated allyl sulfone 5 to unsaturated esters of type 2 takes place α-regioselectively and almost exclusively in an anti fashion (where the syn and anti

• by X-ray analysis) to have the 3R,4S absolute configuration [1]. It was important to examine the effect of other aromatic substituents Ar in amino-substituted sulfone 1 and their influence on this remote induction of chirality, in the hope of further improving the remote diastereoselectivity. We