Synthesis of π-conjugated polycyclic compounds by late-stage extrusion of chalcogen fragments

• Aissam Okba,
• Pablo Simón Marqués,
• Kyohei Matsuo,
• Naoki Aratani,
• Hiroko Yamada,
• Gwénaël Rapenne and
• Claire Kammerer

Beilstein J. Org. Chem. 2024, 20, 287–305, doi:10.3762/bjoc.20.30

• , were synthesized as direct soluble precursors of PBIs 6a,b, along with the corresponding oxides, namely sulfoxides 4a,b and sulfone 5 (Scheme 4). An X-ray crystal structure of the extended thiepine 3b confirmed its bent structure, with a protrusion of the sulfur atom out of the π-surface (Figure 1). As

• series of thiepines 3a–d could finally be smoothly oxidized to give the corresponding sulfoxides 4a–d in high yields. Thermogravimetric analysis of these thiepine S-oxides interestingly revealed that the temperature required for SO-extrusion is almost independent of the nature of the imide substituents

Anion–π catalysis on carbon allotropes

• M. Ángeles Gutiérrez López,
• Mei-Ling Tan,
• Giacomo Renno,
• Augustina Jozeliūnaitė,
• J. Jonathan Nué-Martinez,
• Javier Lopez-Andarias,
• Naomi Sakai and
• Stefan Matile

Beilstein J. Org. Chem. 2023, 19, 1881–1894, doi:10.3762/bjoc.19.140

• level. Compared to the sulfoxides in 46, the catalytic activity of dyad 47 decreased rather than increased despite stronger π acidity. Supported by computational predictions [80][81], record activities in anion–π catalysis with fullerene dimers called for higher oligomers. However, synthetic efforts

Selective and scalable oxygenation of heteroatoms using the elements of nature: air, water, and light

• Damiano Diprima,
• Hannes Gemoets,
• Stefano Bonciolini and
• Koen Van Aken

Beilstein J. Org. Chem. 2023, 19, 1146–1154, doi:10.3762/bjoc.19.82

• of heteroatoms, making them a promising alternative to traditional oxidants in the chemical industry [9]. Our interest in sustainable oxidation methodologies led us to study the selective oxidation of various heteroatoms to their corresponding oxides, including sulfides to sulfoxides, phosphine to

• retardants [14]. Sulfoxides are prominent pharmaceutical ingredients, while phosphine oxides improve solubility of corresponding compounds [15] and have applications in catalysis and materials science [16]. Selenoxides find use as oxygen transfer agents and donor ligands in metal catalysis and organic

1,4-Dithianes: attractive C2-building blocks for the synthesis of complex molecular architectures

• Bram Ryckaert,
• Ellen Demeyere,
• Frederick Degroote,
• Hilde Janssens and
• Johan M. Winne

Beilstein J. Org. Chem. 2023, 19, 115–132, doi:10.3762/bjoc.19.12

• excess of a perbenzoic acid, as shown for the oxidation of 6 to 7 [33][34]. Partial oxidations are also possible, but lead to mixtures of sulfoxides, including cis- and trans-sulfoxide stereoisomers (see also chapter 6). For a more detailed and extensive discussion of the synthesis of 1,4-dithiin

• , including cross-coupling-type chemistries on a conformationally stable cis-vinyl zinc building block. 3 Diels–Alder reactivity of 1,4-dithiin-based dienophiles and dienes Vinyl sulfones and vinyl sulfoxides are classical synthetic equivalents of ethylene in Diels–Alder reactions, and have been widely used

• an oxidation of one of the ring sulfur atoms in a dihydrodithiin building block (Scheme 21) [115]. Controlling the regioselectivity of the monooxidation is often not trivial, but the sulfoxides 132 and 133 can be separated and allow access to various derivatives through addition of a suitable

Reductive opening of a cyclopropane ring in the Ni(II) coordination environment: a route to functionalized dehydroalanine and cysteine derivatives

• Oleg A. Levitskiy,
• Olga I. Aglamazova,
• Yuri K. Grishin and
• Tatiana V. Magdesieva

Beilstein J. Org. Chem. 2022, 18, 1166–1176, doi:10.3762/bjoc.18.121

• fluorination of arylcyclopropane derivatives was reported recently [46][47], difluorinated or oxyfluorinated products were obtained [47]. Notably, anodic fluorination of cyclopropane derivatives bearing arylthio groups gives rise to a variety of possible reaction paths yielding monofluorinated sulfoxides as

Synthetic strategies toward 1,3-oxathiolane nucleoside analogues

• Umesh P. Aher,
• Dhananjai Srivastava,
• Girij P. Singh and
• Jayashree B. S

Beilstein J. Org. Chem. 2021, 17, 2680–2715, doi:10.3762/bjoc.17.182

• derivative 17. This was obtained as a mixture of endo- and exo-sulfoxides. Esterification of 17 was carried out with dimethyl sulfate to give methyl ester 18, which was further reduced using dichloroborane and dimethyl sulfide to provide sulfide 19 in 80% yield in THF as solvent. Hydrolysis of compound 19

Catalyzed and uncatalyzed procedures for the syntheses of isomeric covalent multi-indolyl hetero non-metallides: an account

• Ranadeep Talukdar

Beilstein J. Org. Chem. 2021, 17, 2102–2122, doi:10.3762/bjoc.17.137

• to re-participate in the reaction (Scheme 15b). There are several uses of sulfoxides as a thiol-free sulfur source for introducing sulfur at the indole C3 position [84][85][86]. In 2013, Hamashima reported a synthesis of di(indol-3-yl)sulfide (105a) by reacting indole with DMSO in the presence of

• . Synthesis of bis(indol-3-yl)sulfides using N-silylated 3-bromoindole 93. Fischer indole synthesis of bis(indol-3-yl)sulfides using thio diketones. Oxidative synthesis of bis(indol-3-yl)sulfides using indoles and elemental sulfur. Synthesis of bis(indol-3-yl)sulfides using sulfoxides as sulfur source

Fritsch–Buttenberg–Wiechell rearrangement of magnesium alkylidene carbenoids leading to the formation of alkynes

• Tsutomu Kimura,
• Koto Sekiguchi,
• Akane Ando and
• Aki Imafuji

Beilstein J. Org. Chem. 2021, 17, 1352–1359, doi:10.3762/bjoc.17.94

• Tsutomu Kimura Koto Sekiguchi Akane Ando Aki Imafuji Department of Chemistry, Graduate School of Science, Tokyo University of Science, 1-3 Kagurazaka, Shinjuku-ku, Tokyo 162-8601, Japan 10.3762/bjoc.17.94 Abstract A series of 1-heteroatom-substituted vinyl p-tolyl sulfoxides were prepared and

• treated with organometallic reagents to evaluate which combination of sulfoxides and organometallic reagents yielded alkynes the most efficiently. The use of 1-chlorovinyl p-tolyl sulfoxide and isopropylmagnesium chloride was optimal for this purpose. A variety of 1-chlorovinyl p-tolyl sulfoxides were

• magnesium alkylidene carbenoids was studied by using 13C-labeled sulfoxides and by using DFT calculations. Keywords: alkyne; 1-chlorovinyl p-tolyl sulfoxide; DFT calculation; Fritsch–Buttenberg–Wiechell rearrangement; magnesium alkylidene carbenoid; Introduction Alkynes are important compounds in organic

A comprehensive review of flow chemistry techniques tailored to the flavours and fragrances industries

• Guido Gambacorta,
• James S. Sharley and
• Ian R. Baxendale

Beilstein J. Org. Chem. 2021, 17, 1181–1312, doi:10.3762/bjoc.17.90

Metal-free synthesis of biarenes via photoextrusion in di(tri)aryl phosphates

• Hisham Qrareya,
• Lorenzo Meazza,
• Stefano Protti and
• Maurizio Fagnoni

Beilstein J. Org. Chem. 2020, 16, 3008–3014, doi:10.3762/bjoc.16.250

• Truce–Smiles rearrangement in aryl sulfonamides and aryl phenylsulfonates [44][45][46] or the [3,3]-sigmatropic rearrangement of sulfonium salts arising from the reaction of aryl sulfoxides and phenols [47]. To overcome this problem, the use of a metal catalyst (mainly Ni) was mandatory as reported for

Recent developments in enantioselective photocatalysis

• Callum Prentice,
• James Morrisson,
• Andrew D. Smith and
• Eli Zysman-Colman

Beilstein J. Org. Chem. 2020, 16, 2363–2441, doi:10.3762/bjoc.16.197

• ]. A similar mechanism is proposed for the deracemisation of sulfoxides rac-197; however, the enantioselectivities are lower (5 examples, up to 78:22 er), which the authors attribute to the catalyst differentiating between the sterics of an oxygen atom and a lone pair of electrons (Scheme 30a) [87

Pauson–Khand reaction of fluorinated compounds

• Jorge Escorihuela,
• Daniel M. Sedgwick,
• Alberto Llobat,
• Mercedes Medio-Simón,
• Pablo Barrio and
• Santos Fustero

Beilstein J. Org. Chem. 2020, 16, 1662–1682, doi:10.3762/bjoc.16.138

• , mild oxidizing additives such as amine oxides, aminophosphines, phosphine oxides, and sulfoxides may be used as promoters to facilitate the dissociation step, by oxidatively removing one of the CO ligands in form of CO2 [40]. The most common oxidants are N-morpholine N-oxide (NMO), trimethylamine N

Recent applications of porphyrins as photocatalysts in organic synthesis: batch and continuous flow approaches

• Rodrigo Costa e Silva,
• Luely Oliveira da Silva,
• Aloisio de Andrade Bartolomeu,
• Timothy John Brocksom and
• Kleber Thiago de Oliveira

Beilstein J. Org. Chem. 2020, 16, 917–955, doi:10.3762/bjoc.16.83

• chemical quenching leading to the formation of covalent products [67]. Sulfur oxidation: One of the first examples reported for heteroatom oxidation by singlet oxygen was the oxidation of sulfides to sulfoxides [67]. Sulfoxides are important intermediates in organic synthesis, and with applications in

• porphyrins as photocatalysts under sunlight irradiation furnished the corresponding sulfoxides with high chemoselectivity (up to 100%), scalability (up to 2.6 mmol) and high yields (up to 100%) [94]. According to the authors, the protonation of the porphyrins causes a red-shift of the photosensitizer with an

• sulfides to sulfoxides via oxidation by singlet oxygen [97]. A series of sulfides was oxidized to the corresponding sulfoxides in 87–94% yields using only 0.05 mol % of the photocatalyst (TON: 1880) (Scheme 46). The controlled oxidation of sulfides to sulfoxides by singlet oxygen was also reported using

A review of asymmetric synthetic organic electrochemistry and electrocatalysis: concepts, applications, recent developments and future directions

• Munmun Ghosh,
• Valmik S. Shinde and
• Magnus Rueping

Beilstein J. Org. Chem. 2019, 15, 2710–2746, doi:10.3762/bjoc.15.264

• aryl sulfides 40 to their corresponding sulfoxides 41 using poly(amino acid)-coated platinum electrodes with moderate yield and good to excellent enantiomeric excess (Scheme 17) [47][48]. Osa and co-workers, in 1994, made an important contribution in the area by developing an enantioselective method

Fluorine-containing substituents: metabolism of the α,α-difluoroethyl thioether motif

• Andrea Rodil,
• Alexandra M. Z. Slawin,
• Nawaf Al-Maharik,
• Ren Tomita and
• David O’Hagan

Beilstein J. Org. Chem. 2019, 15, 1441–1447, doi:10.3762/bjoc.15.144

• compounds that are of commercial significance [8][9][10]. Metabolism studies in both of these cases show that the major metabolites are their corresponding sulfoxides (Ar–S(O)CF3) and sulfones (Ar–S(O)2CF3) [8][9]. Indeed, in the case of the insecticide fipronil it is actually the sulfoxide (Ar–S(O)CF3

• 19F NMR spectrum consistent with non-equivalence of the fluorines, immediately indicative of sulfoxide formation. Isolation and subsequent 1H and 19F NMR analyses as well as high-resolution mass spectrometry secured the identity of these metabolites as sulfoxides 6 and 7 and sulfone 8. The structure

• methods developed for the synthesis of enantiomerically enriched aryl fluoroalkyl sulfoxides, however, this appears to be the first enzymatic approach [23][24][25]. Although the fungus was able to both oxidise the sulfur and demethylate the para-methoxy group of 4, there was no obvious presence of novel

Synthesis of non-racemic 4-nitro-2-sulfonylbutan-1-ones via Ni(II)-catalyzed asymmetric Michael reaction of β-ketosulfones

• Alexander N. Reznikov,
• Anastasiya E. Sibiryakova,
• Marat R. Baimuratov,
• Eugene V. Golovin,
• Victor B. Rybakov and
• Yuri N. Klimochkin

Beilstein J. Org. Chem. 2019, 15, 1289–1297, doi:10.3762/bjoc.15.127

• that the reaction of β-keto phosphonates with nitroalkenes in the presence of Ni(II) complexes with chiral vicinal diamines was carried out not only with excellent enantioselectivity, but also diastereoselectivity [55]. Moreover, β-keto sulfoxides react with nitroalkenes under catalysis by Ni(II

• by the coordination of β-ketosulfones through the oxygen atom of the sulfonyl group with Ni. For example, sulfoxide complexes with O-coordination of the corresponding ligands are widely known [57]. Although the donor properties of sulfones are lower than those of sulfoxides. Results and Discussion

Electrophilic oligodeoxynucleotide synthesis using dM-Dmoc for amino protection

• Shahien Shahsavari,
• Dhananjani N. A. M. Eriyagama,
• Bhaskar Halami,
• Vagarshak Begoyan,
• Marina Tanasova,
• Jinsen Chen and
• Shiyue Fang

Beilstein J. Org. Chem. 2019, 15, 1116–1128, doi:10.3762/bjoc.15.108

• ]. The dithioketal groups in the dM-Dmoc and Dmoc functions of 32 were then oxidized with a solution of sodium periodate at room temperature to give 33. The 5'-trityl tag survived the conditions. It should be pointed out that some sulfoxides might be further oxidized to sulfones, which should not affect

Thiol-free chemoenzymatic synthesis of β-ketosulfides

• Adrián A. Heredia,
• Martín G. López-Vidal,
• Marcela Kurina-Sanz,
• Fabricio R. Bisogno and
• Alicia B. Peñéñory

Beilstein J. Org. Chem. 2019, 15, 378–387, doi:10.3762/bjoc.15.34

• generate the corresponding chiral sulfoxides or sulfone derivatives [32]. Multicomponent reactions (MCRs), in which three or more reagents react giving rise to generally complex molecules in one-pot, have arisen as a powerful tool to connect fragments in a simple manner, avoiding cost and time-consuming

An overview on recent advances in the synthesis of sulfonated organic materials, sulfonated silica materials, and sulfonated carbon materials and their catalytic applications in chemical processes

• Hashem Sharghi,
• Pezhman Shiri and
• Mahdi Aberi

Beilstein J. Org. Chem. 2018, 14, 2745–2770, doi:10.3762/bjoc.14.253

• efficient and reusable catalyst for rapid oxidation of a series of aromatic and aliphatic sulfides at room temperature under aqueous medium. The simplicity of the process, chemoselectivity towards sulfoxides, and recyclability at least for eleven runs were the merits of this procedure [61]. Zhou et al

Unprecedented nucleophile-promoted 1,7-S or Se shift reactions under Pummerer reaction conditions of 4-alkenyl-3-sulfinylmethylpyrroles

• Takashi Go,
• Akane Morimatsu,
• Hiroaki Wasada,
• Genzoh Tanabe,
• Osamu Muraoka,
• Yoshiharu Sawada and
• Mitsuhiro Yoshimatsu

Beilstein J. Org. Chem. 2018, 14, 2722–2729, doi:10.3762/bjoc.14.250

• -diynes with secondary amines resulted in the formation of 3-sulfanylmethyl-4-aminomethylpyrroles (Scheme 1) [32][33]. The sulfanyl group of pyrroles is easily oxidised to produce their corresponding sulfoxides. When we performed the Pummerer reaction and cyclization of pyrrolesulfoxides to obtain their

• corresponding pyrroloazepines, we observed unprecedented events, i.e., 1,7-sulfanyl group (1,7-S) shift reactions, on the cation intermediates. Herein, we report the unique 1,7-S and 1,7-Se shift reactions through Pummerer reactions of alkenyl pyrrolomethyl sulfoxides and the corresponding successive

• cyclisation reactions. Results and Discussion We prepared sulfoxides as substrates for the Pummerer reactions according to the aforementioned method [32][33]; subsequently, oxidation with mCPBA was performed (Scheme 2). Both the allylic sulfides 4a–f and their sulfoxides 5a–f were obtained in good to high

β-Hydroxy sulfides and their syntheses

• Mokgethwa B. Marakalala,
• Edwin M. Mmutlane and
• Henok H. Kinfe

Beilstein J. Org. Chem. 2018, 14, 1668–1692, doi:10.3762/bjoc.14.143

• . Carrying out the one-pot thiolysis then oxidation with hydrogen peroxide proceeded uneventfully to give the corresponding β-hydroxy sulfoxides 35 and 36 in good to excellent yields (Scheme 7). Moreover, the reaction was found to be compatible with the less nucleophilic thiols such as p-fluorothiophenol and

• oxidation to β-hydroxy sulfoxides under microwave irradiation. Gallium triflate-catalyzed ring opening of epoxides and one-pot oxidation. Thiolysis of epoxides and one-pot oxidation to β-hydroxy sulfoxides using Ga(OTf)3 as a catalyst. Ring opening of epoxide using ionic liquids under solvent-free

A survey of chiral hypervalent iodine reagents in asymmetric synthesis

• Soumen Ghosh,
• Suman Pradhan and
• Indranil Chatterjee

Beilstein J. Org. Chem. 2018, 14, 1244–1262, doi:10.3762/bjoc.14.107

• derivatives of L-tartaric acid anhydrides in 1986. A promising asymmetric induction was achieved for the oxidation of sulfides 23 to sulfoxides 24. This marked the beginning of an era of asymmetric oxidation of sulfides. However, the presence of C2 symmetry in the chiral unit is essential to obtain decent

• enantioselectivity [24]. Later, Kita et al. used chiral tartaric acid derivatives to synthesize chiral I(V) reagents 2 from PhIO2. This represented the first example of the catalytic use of chiral hypervalent reagents in the oxidation of sulfides to sulfoxides with decent enantioselectivities (ees, Scheme 2a). The

• sulfides to sulfoxides with good yields but with poor enantioselectivity (Scheme 2b) [27]. Later, Zhdankin et al. synthesized different classes of chiral I(V) reagents 4 based on various amino acids as sources of chirality. The oxidation of the readily available 2-iodobenzamides (synthesized from amino

Photocatalytic formation of carbon–sulfur bonds

• Alexander Wimmer and
• Burkhard König

Beilstein J. Org. Chem. 2018, 14, 54–83, doi:10.3762/bjoc.14.4

• . General concepts, synthetic strategies and the substrate scope of reactions yielding thiols, disulfides, sulfoxides, sulfones and other organosulfur compounds are discussed together with the proposed mechanistic pathways. Keywords: disulfides; photocatalysis; sulfones; sulfoxides; thiols; visible light

• disulfide, thioamide derivatives and sulfides Disulfides and thiosulfates Sulfoxides Sulfinic acids, sulfinate salts and sulfinamides Sulfonyl halides, sulfonyl hydrazines, thionyl chloride and sulfur dioxide C–S bond formations initiated by irradiation with light of wavelengths shorter than 380 nm or by

• radical initiators as well as photocatalytic reactions, where sulfur-containing substrates act as a sacrificial agent are not discussed in this review [23][24][25][26][27][28]. Review Thiols Formation of sulfides and sulfoxides A large number of photocatalytic C–S bond-forming methods report the

Preactivation-based chemoselective glycosylations: A powerful strategy for oligosaccharide assembly

• Weizhun Yang,
• Bo Yang,
• Sherif Ramadan and
• Xuefei Huang

Beilstein J. Org. Chem. 2017, 13, 2094–2114, doi:10.3762/bjoc.13.207

• the type of glycosyl donors that can undergo a preactivation-based chemoselective glycosylation with an emphasis on thioglycosides due to their wide applicability. Preactivation of glycosyl sulfoxides: early success of preactivation One of the earliest preactivation-based glycosylation reactions

• [18]. This protocol is found to be applicable to a wide range of glycosyl-donor types including thioglycosides, glycosyl sulfoxides, glycosyl hemiacetals, selenoglycosides, and 2-pyridyl glycosides. The newly formed oligosaccharide intermediate could be directly subjected to another round of

Chiral phase-transfer catalysis in the asymmetric α-heterofunctionalization of prochiral nucleophiles

• Johannes Schörgenhumer,
• Maximilian Tiffner and
• Mario Waser

Beilstein J. Org. Chem. 2017, 13, 1753–1769, doi:10.3762/bjoc.13.170

• investigation of different cyclic and acyclic sulfoxides 29, they could show that the diastereoselectivity of this reaction can be clearly improved by using the chiral cinchona alkaloid-based ammonium salt A8 compared to the use of achiral tetraalkylammonium salt-based PTCs [127][128][129]. In 2013, Maruoka’s