Ultrasound-promoted organocatalytic enamine–azide [3 + 2] cycloaddition reactions for the synthesis of ((arylselanyl)phenyl-1H-1,2,3-triazol-4-yl)ketones

• Gabriel P. Costa,
• Natália Seus,
• Juliano A. Roehrs,
• Raquel G. Jacob,
• Ricardo F. Schumacher,
• Thiago Barcellos,
• Rafael Luque and
• Diego Alves

Beilstein J. Org. Chem. 2017, 13, 694–702, doi:10.3762/bjoc.13.68

• 1,2,3-triazoles [33][34][35][36][37]. Selanyltriazoyl carboxylates, carboxamides, carbonitriles or sulfones were synthesized in good to excellent yields using catalytic amounts of an organocatalyst. Organoselenium compounds are attractive synthetic targets because of their selective reactions [38][39

1H-Imidazol-4(5H)-ones and thiazol-4(5H)-ones as emerging pronucleophiles in asymmetric catalysis

• Antonia Mielgo and
• Claudio Palomo

Beilstein J. Org. Chem. 2016, 12, 918–936, doi:10.3762/bjoc.12.90

• the pionnering work by Trost in 2004 [26], several examples of the utility of the structurally related oxazol-4(5H)-ones (Figure 1b, X = O) have also been published, which involve mainly Michael additions (to enones [27][28], nitroalkenes [29][30], alkynones [31][32][33] and vinyl sulfones [34]), γ

Enantioselective carbenoid insertion into C(sp³)–H bonds

• J. V. Santiago and
• A. H. L. Machado

Beilstein J. Org. Chem. 2016, 12, 882–902, doi:10.3762/bjoc.12.87

• evidence of the carbenoid intermediates formation. In 2010, Maguire et al. studied the enantioselective insertion of copper carbenoid derived from α-diazosulfones into C(sp3)–H bonds [10]. In this work, the authors produced cyclic sulfones (thiopyrans) 52 with high enantioselectivity by using a combination

• of 5 mol % of copper chloride salt, 6 mol % of ligand 1c and 6 mol % of sodium tetrakis[(3,5-tri-fluoromethyl)phenyl]borate (NaBARF). The cyclic sulfones 52 were obtained in good yields and excellent enantiomeric excesses (85–98%) favoring the cis-1,2-di-substituted stereoisomer (Table 5). The

• authors also performed the copper carbenoid insertion reaction to yield five-membered cyclic sulfones 54, under similar experimental conditions, in moderate yields and enantiomeric excesses of the trans stereoisomer (Table 6). Independent to the size of the product, the authors emphasize the low

Recent advances in N-heterocyclic carbene (NHC)-catalysed benzoin reactions

• Rajeev S. Menon,
• Akkattu T. Biju and
• Vijay Nair

Beilstein J. Org. Chem. 2016, 12, 444–461, doi:10.3762/bjoc.12.47

• -benzoin cascade process involving enals and β-oxo sulfones to generate enantioenriched cyclopentanone derivatives with three contiguous stereocentres. A dual secondary amine/NHC catalytic system comprising of the prolinol 60 and NHC precatalyst 22 was found to give the best results (Scheme 39) [56]. The

• enals and β-oxo sulfones. Intramolecular benzoin condensation of carbohydrate-derived dialdehydes. Enantioselective intramolecular benzoin reactions of N-tethered keto-aldehydes. Asymmetric cross-benzoin reactions promoted by camphor-derived catalysts. NHC-Brønsted base co-catalysis in a benzoin–Michael

Diastereoselective Ugi reaction of chiral 1,3-aminoalcohols derived from an organocatalytic Mannich reaction

• Samantha Caputo,
• Andrea Basso,
• Lisa Moni,
• Renata Riva,
• Valeria Rocca and
• Luca Banfi

Beilstein J. Org. Chem. 2016, 12, 139–143, doi:10.3762/bjoc.12.15

• -selective organocatalysts. We prepared two known carbamoyl sulfones 1 [30][31] and transformed them without isolation of intermediates into a series of five Boc-protected β-aminoalcohols 4a–e (Scheme 2). Using caesium carbonate, carbamoyl sulfones were converted into the corresponding N-Boc-protected imines

• diastereoselectivity inversion might be due to the different solvent and not to the structure of isocyanide. The synthetic route from carbamoyl sulfones 1 to peptidomimetics 6 is quite short: intermediate purification was carried out only at the level of the Boc-protected aminoalcohols 4 and of the final products 6

Facile synthesis of 4H-chromene derivatives via base-mediated annulation of ortho-hydroxychalcones and 2-bromoallyl sulfones

• Srinivas Thadkapally,
• Athira C. Kunjachan and
• Rajeev S. Menon

Beilstein J. Org. Chem. 2016, 12, 16–21, doi:10.3762/bjoc.12.3

• Srinivas Thadkapally Athira C. Kunjachan Rajeev S. Menon Medicinal Chemistry and Pharmacology Division, CSIR-Indian Institute of Chemical Technology, Hyderabad 500 007, India 10.3762/bjoc.12.3 Abstract The cesium carbonate-mediated reaction of 2-bromoallyl sulfones and ortho-hydroxychalcones

• furnished 3-arylsulfonyl-4H-chromene derivatives in 58–67% yield (18 examples). 2-Bromoallyl sulfones functioned as synthetic surrogates for allenyl sulfones in the reaction. Keywords: allenes; chromenes; cyclocondenzation; sulfones; vinylic substitution; Findings Benzo[b]dihydropyran, commonly known as

• sulfones [16][17], we became interested in the possibility of exploiting allenyl sulfones as a building block for heterocyclic sulfones. The synthetic potential of allenyl sulfones remains largely unexploited. This is in sharp contrast with the widespread use of electronically similar allenyl esters

Lewis acid-promoted hydrofluorination of alkynyl sulfides to generate α-fluorovinyl thioethers

• Davide Bello and
• David O'Hagan

Beilstein J. Org. Chem. 2015, 11, 1902–1909, doi:10.3762/bjoc.11.205

• somewhat scarce. The only account we are aware of involves the AIBN-promoted thiodesulfonylation of aromatic fluorovinyl sulfones as reported by Wnuk [12], a reaction which works in varying yields and stereoselectivities. Following from our previous experience [7] with terminal acetylene thioethers, we now

Design and synthesis of polycyclic sulfones via Diels–Alder reaction and ring-rearrangement metathesis as key steps

• Sambasivarao Kotha and
• Rama Gunta

Beilstein J. Org. Chem. 2015, 11, 1373–1378, doi:10.3762/bjoc.11.148

• Sambasivarao Kotha Rama Gunta Department of Chemistry, Indian Institute of Technology-Bombay, Powai, Mumbai-400 076, India, Fax: 022-25767152 10.3762/bjoc.11.148 Abstract Here, we describe a new and simple synthetic strategy to various polycyclic sulfones via Diels–Alder reaction and ring

• -rearrangement metathesis (RRM) as the key steps. This approach delivers tri- and tetracyclic sulfones with six (n = 1), seven (n = 2) or eight-membered (n = 3) fused-ring systems containing trans-ring junctions unlike the conventional all cis-ring junctions generally obtained during the RRM sequence

• . Interestingly the starting materials used are simple and commercially available. Keywords: alkenylation; Diels–Alder reaction; ring-rearrangement metathesis; sulfones; Introduction Sulfones [1][2][3][4][5][6][7][8] are popular building blocks [9] in organic synthesis. They are also useful substrates for the

Selected synthetic strategies to cyclophanes

• Sambasivarao Kotha,
• Mukesh E. Shirbhate and
• Gopalkrushna T. Waghule

Beilstein J. Org. Chem. 2015, 11, 1274–1331, doi:10.3762/bjoc.11.142

• ) in quantitative yield. Next, bis-sulfone 239 was reacted with 5-bromo-1-pentene (240) in the presence of NaH to give an inseparable mixture of cis and trans-sulfones 241a and 241b, respectively. An RCM sequence of these sulfones in the presence of the G-I (12) catalyst gave cyclophane 243 (51%) and

Regioselective synthesis of chiral dimethyl-bis(ethylenedithio)tetrathiafulvalene sulfones

• Flavia Pop and
• Narcis Avarvari

Beilstein J. Org. Chem. 2015, 11, 1105–1111, doi:10.3762/bjoc.11.124

• conformation. Cyclic voltammetry measurements indicate fully reversible oxidation in radical cation and dication species. Keywords: chirality; crystal structures; molecular materials; sulfones; tetrathiafulvalenes; Introduction Chiral tetrathiafulvalene (TTF) derivatives have been addressed for the first

• possibilities hardly addressed so far in TTF chemistry is the oxidation of the sulfur atoms into sulfoxides or sulfones. Indeed, only two reports deal with the oxidation of BEDT-TTF into BEDT-TTF monosulfoxides (Scheme 1), along with enantioselectivity issues [27][28]. We describe herein the synthesis

• very important aspect related to the interest of these chiral TTF sulfones as precursors for molecular conductors is the stability of the radical cation species. As mentioned earlier, the major drawback of the inner BEDT-TTF sulfoxides is their irreversible oxidation, as the radical cations once

Hetero-Diels–Alder reactions of hetaryl and aryl thioketones with acetylenic dienophiles

• Grzegorz Mlostoń,
• Paulina Grzelak,
• Maciej Mikina,
• Anthony Linden and
• Heinz Heimgartner

Beilstein J. Org. Chem. 2015, 11, 576–582, doi:10.3762/bjoc.11.63

• sulfones. Keywords: dimethyl acetylenedicarboxylate (DMAD); hetero-Diels–Alder reactions; high pressure reactions; methyl propiolate; thioketones; thiopyrans; Introduction A series of recent publications evidence that, in contrast to earlier opinions, thioketones are useful building blocks for the

• examine the reactions of diverse hetaryl thioketones with both 2a and methyl propiolate (2b). Moreover, along with standard procedures, the high-pressure technique was applied. Finally, selected examples of the obtained polycyclic 2H-thiopyrans were oxidized to give the corresponding sulfones. Results and

• the present study were used for oxidation reactions aimed at the preparation of the corresponding sulfoxides and sulfones. As demonstrated in a recent publication [20], polycyclic sulfones are attractive substrates for the synthesis of polycyclic hydrocarbons via thermal SO2 extrusion. In our

The Shono-type electroorganic oxidation of unfunctionalised amides. Carbon–carbon bond formation via electrogenerated N-acyliminium ions

• Alan M. Jones and
• Craig E. Banks

Beilstein J. Org. Chem. 2014, 10, 3056–3072, doi:10.3762/bjoc.10.323

• azabicylco-N-oxyl was employed to kinetically resolve racemic sec-alcohols (Scheme 9). The preparation of 1-(N-acylamino)alkyl sulfones from the anodic electrooxidation of non-Kolbe or Shono-type precursors affords the expected α-methoxyl products. Treatment with triphenylphosphonium salts and sodium aryl

Synthesis of nanodiamond derivatives carrying amino functions and quantification by a modified Kaiser test

• Gerald Jarre,
• Steffen Heyer,
• Elisabeth Memmel,
• Thomas Meinhardt and
• Anke Krueger

Beilstein J. Org. Chem. 2014, 10, 2729–2737, doi:10.3762/bjoc.10.288

• function. Throughout the transformation the surface loading (see TGA data and elemental analysis in the experimental part) with the organic moieties remains the same showing the high stability of the double grafting by covalent C–C bonds. However, during the oxidation of the thioethers to the sulfones a

• the sulfones (see spectra c) and d) in Figure 2). A control experiment using nanodiamond not functionalized with the pyrimidine proved the reactivity of surface groups of the nanodiamond (CH, OH, π-bonds etc. are present on thermally annealed nanodiamond [18]) with MCPBA showing the formation of

End-group-functionalized poly(N,N-diethylacrylamide) via free-radical chain transfer polymerization: Influence of sulfur oxidation and cyclodextrin on self-organization and cloud points in water

• Sebastian Reinelt,
• Daniel Steinke and
• Helmut Ritter

Beilstein J. Org. Chem. 2014, 10, 680–691, doi:10.3762/bjoc.10.61

• sulfide) containing copolymers is based on the oxidation of thioethers to more hydrophilic sulfoxides or sulfones [11][12]. The specific sulfoxidation of a polymer bound end-group, which is in the focus of our present work, has not yet been investigated. Polymeric materials exhibiting sensitivity to

Recent advances in transition metal-catalyzed Csp²-monofluoro-, difluoro-, perfluoromethylation and trifluoromethylthiolation

• Grégory Landelle,
• Armen Panossian,
• Sergiy Pazenok,
• Jean-Pierre Vors and
• Frédéric R. Leroux

Beilstein J. Org. Chem. 2013, 9, 2476–2536, doi:10.3762/bjoc.9.287

• stability of molecules in acidic medium. One can place this substituent next to the ever-present CF3 and the emerging OCF3 substituent [55][56][130]. In contrast, aryl trifluoromethyl sulfides are key intermediates for the preparation of trifluoromethyl sulfoxides or sulfones. Aryl trifluoromethyl sulfides

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

• rationale for the stereoselective formation of 19 is the thermodynamic stability due to the double anomeric effect. Oxidation of the alcohol 19 with SO3∙pyr/Et3N/DMSO [21] afforded aldehyde 20. Next, we carried out the synthesis of PT-sulfones 23 and 24 which were the coupling partners of the aldehyde 20

• /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

• elucidation is currently underway and will be reported in due course. Structure of symbiodinolide (1). Our previous synthesis of the C79–C96 fragment 7. Retrosynthetic analysis of the C79–C97 fragment 8. Synthesis of aldehyde 20. Synthesis of PT-sulfones 23 and 24. Synthesis of the C79–C97 fragment 27. Julia

Gold-catalyzed intermolecular coupling of sulfonylacetylene with allyl ethers: [3,3]- and [1,3]-rearrangements

• Jungho Jun,
• Hyu-Suk Yeom,
• Jun-Hyun An and
• Seunghoon Shin

Beilstein J. Org. Chem. 2013, 9, 1724–1729, doi:10.3762/bjoc.9.198

• + 2 + 2] reactions with alkenes [6]. On the other hand, Shin and co-workers have adopted propiolic acids and alkynyl sulfones for formal enyne cross metathesis (f-EYCM) [5]. These examples allow for an effective alkyne–alkene coupling under mild reaction conditions (rt) with as little as 1.5 ~ 2 equiv

• is highly effective in promoting the reaction under a mild condition with relatively low amount of excess reactants. We report herein the details of our investigation on the intermolecular reactions of alkynyl sulfones with allyl ethers aimed at definition of the substrate scope and at elucidation of

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

• Science Hall, Notre Dame, IN, 46556, USA 10.3762/bjoc.9.159 Abstract Dipolar addition of cyclic azomethine imines with cyclic vinyl sulfones gave rise to functionalized tricycles that exhibited fluxional behavior in solution at room temperature. The scope of the synthetic methodology was explored, and

• -broadening in the NMR spectra was found to depend on the presence of substitution next to the inverting nitrogen center. Keywords: DFT calculations; dipolar addition; fluxional behavior; sulfones; VT NMR; Introduction The 1,3-dipolar cycloaddition [1][2][3] represents a powerful methodology for the

• 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

Isotopically labeled sulfur compounds and synthetic selenium and tellurium analogues to study sulfur metabolism in marine bacteria

• Nelson L. Brock,
• Christian A. Citron,
• Claudia Zell,
• Martine Berger,
• Irene Wagner-Döbler,
• Jörn Petersen,
• Thorsten Brinkhoff,
• Meinhard Simon and
• Jeroen S. Dickschat

Beilstein J. Org. Chem. 2013, 9, 942–950, doi:10.3762/bjoc.9.108

• ]. This is reflected by their volatile bouquets that are dominated by sulfur compounds such as polysulfides 1 and 2 (Figure 1), thiosulfonates 3, thioesters 4, or sulfones 5, and phenylacetate-derived volatiles such as the moderately antibacterial compounds tropone (6) and tropone hydrate 7 [3][4][5][6

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

• is thus made in just one step. In both of these examples, three C–C bonds and one C–S bond are formed one after the other, resulting in a considerable increase in complexity. Interestingly, and not unexpectedly, the two sulfones in structures 21 and 25 have very different reactivities. For instance

• methods were developed to this end, with perhaps the most versatile relying on the chemistry of sulfones [53]. Aliphatic sulfonyl radicals are able to extrude sulfur dioxide, and the resulting carbon-centred radicals may be used in numerous ways. In particular, they can serve as chain-propagating agents

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

• product 1c in 59% yield. In contrast, allylmagnesiated intermediate 1d reacted with benzaldehyde to give syn-addition product 1e stereoselectively. Marek reported copper-catalyzed carbometalation of alkynyl sulfoximines and sulfones using organozinc reagents of mild reactivity [41]. Various organozinc

• reagents can be used, irrespective of the identity of the organic groups, preparative protocols, and accompanying functional groups (Table 1). Similarly, Xie reported ethyl- or methylzincation of alkynyl sulfones [42] and Tanaka reported carbozincation of alkynyl sulfoxides [43][44]. Marek discovered

Alternaric acid: formal synthesis and related studies

• Michael C. Slade and
• Jeffrey S. Johnson

Beilstein J. Org. Chem. 2013, 9, 166–172, doi:10.3762/bjoc.9.19

• more step-efficient endgame, test substrates were prepared for exploration of a modified Julia olefination [32]. As shown in Scheme 4, the phenyltetrazole heteroaromatic core in sulfones 9a and 9b provided excellent E-/Z- selectivity for formation of the C8–C9 olefin under typical modified Julia

The chemistry of bisallenes

• Henning Hopf and
• Georgios Markopoulos

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

Synthesis of chiral sulfoximine-based thioureas and their application in asymmetric organocatalysis

• Marcus Frings,
• Isabelle Thomé and
• Carsten Bolm

Beilstein J. Org. Chem. 2012, 8, 1443–1451, doi:10.3762/bjoc.8.164

• , sulfoximines 1 (Figure 1) represent an important compound class among the comprehensive group of organosulfur reagents [1][2][3][4]. Being monoaza analogs of sulfones, sulfoximines have fascinated researchers from both academia and industry. Because of their interesting chemical properties and the biological

Palladium-catalyzed substitution of (coumarinyl)methyl acetates with C-, N-, and S-nucleophiles

• Kalicharan Chattopadhyay,
• Erik Fenster,
• Alexander J. Grenning and
• Jon A. Tunge

Beilstein J. Org. Chem. 2012, 8, 1200–1207, doi:10.3762/bjoc.8.133

• anion (Scheme 5). Phenyl (4a–c) and tolyl (4d–e) sulfinates were viable coupling partners, giving the product sulfones in good yield. As previously noted, the coumarin core tolerated various simple electronic (4b,c,e) and alkyl (4a,c,d) substitution patterns. Since (coumarinyl)methylamines are known to