Application of cyclic phosphonamide reagents in the total synthesis of natural products and biologically active molecules

• Thilo Focken and
• Stephen Hanessian

Beilstein J. Org. Chem. 2014, 10, 1848–1877, doi:10.3762/bjoc.10.195

• the adduct as a 3:1 mixture of diastereomers, with 98 as the major isomer. The low diastereoselectivivity observed for the sulfuration as compared to that reported for the alkylation of phosphonamides similar to 97 was explained with a longer C–S bond in the transition state and the steric hindrance

Less reactive dipoles of diazodicarbonyl compounds in reaction with cycloaliphatic thioketones – First evidence for the 1,3-oxathiole–thiocarbonyl ylide interconversion

• Valerij A. Nikolaev,
• Alexey V. Ivanov,
• Ludmila L. Rodina and
• Grzegorz Mlostoń

Beilstein J. Org. Chem. 2013, 9, 2751–2761, doi:10.3762/bjoc.9.309

• spontaneous desulfurization and convert into tetrasubstituted alkenes [20]. 2) Pathway B assumes a stepwise cycloaddition of the diazo-1,3-dipole with the C=S bond leading to the initial formation of the diazonium zwitterion 11. This step is followed either by the ring closure to give thiadiazoline 10 or by

• temperature the formation of 1,3-oxathioles 3,7 occurred not via the initial decomposition of diazo compounds 2 and subsequent generation of thiocarbonyl ylides 6. Instead, the way via the initial [2 + 3]-cycloaddition of the diazo compounds with the C=S bond (Scheme 2) seems to be the most likely process

• . Conclusion We established that acyclic diazodicarbonyl compounds 2a–d react at room temperature with cycloaliphatic thioketones 1a,b via a cascade process, involving either a concerted or a stepwise cycloaddition of the diazo 1,3-dipole to the C=S bond of thioketone, an elimination of the nitrogen from an

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

Efficient Cu-catalyzed base-free C–S coupling under conventional and microwave heating. A simple access to S-heterocycles and sulfides

• Silvia M. Soria-Castro and
• Alicia B. Peñéñory

Beilstein J. Org. Chem. 2013, 9, 467–475, doi:10.3762/bjoc.9.50

• h at 110 °C, has also been reported [52]. As part of our ongoing study on sulfur chemistry, we are interested in the one-pot synthesis of target heterocycles such as the Beaucage reagent and benzothiazole as well as sulfides by using Cu-catalysis to mediate the C–S bond formation. Herein, we report

• acetylation reaction was also observed with 2-iodophenol. In consequence, protected amino and hydroxy groups were required for the copper-mediated C–S bond formation to proceed properly (Table 3, entries 3, 4 and 9). This copper-catalyzed coupling reaction was also applied to heteroaromatic and other

• , versatile, efficient and economically attractive procedure for the synthesis of sulfur heterocycles and a variety of sulfides with good yields. This one-pot methodology involves a cascade of reactions starting with a C–S bond formation by copper catalysis and followed by consecutive acyl transfers

Tricyclic flavonoids with 1,3-dithiolium substructure

• Lucian G. Bahrin,
• Peter G. Jones and
• Henning Hopf

Beilstein J. Org. Chem. 2012, 8, 1999–2003, doi:10.3762/bjoc.8.226

• charge at the nitrogen atom. Similarly, C3–C4, at 1.342(2) Å, is also a (marginally lengthened) double bond. The C–S bond lengths in the five-membered ring are approximately equal [1.727(1) – 1.746(1) Å]. The new 1,3-dithiolium cations are particularly prone to nucleophilic attack at their 2-positions

A simple and efficient dual optical signaling chemodosimeter for toxic Hg(II)

• Sabir H. Mashraqui,
• Sapna A. Tripathi,
• Sushil S. Ghorpade and
• Smita R. Britto

Beilstein J. Org. Chem. 2012, 8, 1352–1357, doi:10.3762/bjoc.8.155

• Hg2+ with the thione group of acrithion 2, forming an intermediate thioacridinium–Hg+ complex. This phenomena would polarize the C=S bond and therefore facilitate nucleophilic attack by water at the electrophilic C9 position. Subsequently, the hydrolytic desulfurization is expected to form compound 1

Chemo-enzymatic modification of poly-N-acetyllactosamine (LacNAc) oligomers and N,N-diacetyllactosamine (LacDiNAc) based on galactose oxidase treatment

• Christiane E. Kupper,
• Ruben R. Rosencrantz,
• Birgit Henßen,
• Helena Pelantová,
• Stephan Thönes,
• Anna Drozdová,
• Vladimir Křen and
• Lothar Elling

Beilstein J. Org. Chem. 2012, 8, 712–725, doi:10.3762/bjoc.8.80

• experiment (bold printed in tables) and confirmed by the downfield glycosylation shift of the involved carbons (C-4 for Glc, C-3 for Gal). Chemical shifts of GlcNAc carbons C-2 agree with N-acetylation. Because of isomerism on the NH-C=S bond, signals of H-1A and CS were not detected. Chemical shifts of

• spin system –(CH2)4CHCH(N–)CH(N–)CH2– of biotin. The anomeric configuration (β) of all saccharide units was determined from the JH-1,H-2 coupling constants. Chemical shifts of GlcNAc carbons C-2 agree with N-acetylation. Because of isomerism on the NH–C=S bond, protons H-1A resonate as two broad

Discovery of practical production processes for arylsulfur pentafluorides and their higher homologues, bis- and tris(sulfur pentafluorides): Beginning of a new era of “super-trifluoromethyl” arene chemistry and its industry

• Teruo Umemoto,
• Lloyd M. Garrick and
• Norimichi Saito

Beilstein J. Org. Chem. 2012, 8, 461–471, doi:10.3762/bjoc.8.53

• %) with p-dichlorobenzene (major) and trichlorobenzene (minor), which were formed by cleavage of the C–S bond, in the case of the major byproduct, and further chlorination, in the case of the minor one, during the reaction. The complete removal of the byproducts from 3f was difficult due to similar

Nano copper oxide catalyzed synthesis of symmetrical diaryl sulfides under ligand free conditions

• K. Harsha Vardhan Reddy,
• V. Prakash Reddy,
• A. Ashwan Kumar,
• G. Kranthi and
• Y.V.D. Nageswar

Beilstein J. Org. Chem. 2011, 7, 886–891, doi:10.3762/bjoc.7.101

• -smelling thiols as the main drawback, which leads to environmental and safety problems. To overcome these problems, Zhou [43] and coworkers recently reported an efficient C–S bond formation by the reaction of potassium thiocyanate and aryl halides in the presence of a copper catalyst and a ligand in

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

• (C–S bond formation). Alternatively, stereoselective alkylation, arylation or acylation of a secondary sulfur-based substrate could generate the quaternary centre (C–C bond formation). Review 1 Carbon–sulfur bond formation 1.1 SN2 displacement of a leaving group Stereospecific nucleophilic attack on

Effects of anion complexation on the photoreactivity of bisureido- and bisthioureido-substituted dibenzobarrelene derivatives

• Heiko Ihmels and
• Jia Luo

Beilstein J. Org. Chem. 2011, 7, 278–289, doi:10.3762/bjoc.7.37

• considered to explain the drastic change of the photochemical properties. Apparently, the quenching effect of the thioureido substituents on the triplet reaction is no longer effective after the association with anions. Presumably, the complexed anions affect the properties of the C=S bond in 1i, leading to

(Pseudo)amide-linked oligosaccharide mimetics: molecular recognition and supramolecular properties

• José L. Jiménez Blanco,
• Fernando Ortega-Caballero,
• Carmen Ortiz Mellet and
• José M. García Fernández

Beilstein J. Org. Chem. 2010, 6, No. 20, doi:10.3762/bjoc.6.20

• –(C=S) bond (Figure 18). β-(1→6)-Linked thioureido-di- and trisaccharides were used to obtain the corresponding ureido- and guanidine-linked oligomers. These compounds were evaluated as phosphate binders in water [76]. Association constants (Kas) for the binding of dimethyl and, especially, phenyl

Diastereoselective functionalisation of benzo-annulated bicyclic sultams: Application for the synthesis of cis-2,4-diarylpyrrolidines

• Susan Kelleher,
• Pierre-Yves Quesne and
• Paul Evans

Beilstein J. Org. Chem. 2009, 5, No. 69, doi:10.3762/bjoc.5.69

• and 6b which were used as substrates for the N–S and C–S bond cleavage forming arylsubstituted pyrrolidines [1][2][3]. In relation to this sequence attempts to achieve a reductive Heck cyclisation employing ammonium formate [12], gave only the product of bromine-hydrogen exchange 4c (where X = H

Variations in product in reactions of naphthoquinone with primary amines

• Marjit W. Singh,
• Anirban Karmakar,
• Nilotpal Barooah and
• Jubaraj B. Baruah

Beilstein J. Org. Chem. 2007, 3, No. 10, doi:10.1186/1860-5397-3-10

•  3c). Surprisingly in this reaction the product formed is through C-S bond formation rather than C N-bond formation (Scheme 4). The presence of a few well-separated peaks of the products from the starting materials in the NMR spectra (designated by A) shows the formation of the one product with time

• rings are perpendicular to each other. The C-S bond formation reaction can be extended to other thiols such as thiophenol and 4-methoxythiophenol, 4-bromothiophenol etc. with 1,4-naphthoquinone as well as 1,4-benzoquinone. The difference in the case of reaction of 1,4-benzoquinone with primary amine

• whereas similar reaction of 1,4-napthoquinone leads to C-S bond formation. The advantage of these reactions is mildness and versatility. C-N as well as C-S bond formation can be achieved in quinonic compounds under mild conditions. However, limited mechanistic understanding of the reactions is the

Generation of pyridyl coordinated organosilicon cation pool by oxidative Si-Si bond dissociation

• Toshiki Nokami,
• Ryoji Soma,
• Yoshimasa Yamamoto,
• Toshiyuki Kamei,
• Kenichiro Itami and
• Jun-ichi Yoshida

Beilstein J. Org. Chem. 2007, 3, No. 7, doi:10.1186/1860-5397-3-7

• C-S bond dissociation. Very recently, the oxidative C-C bond dissociation has been found to be effective for generation of a pool of a carbocation having a stabilizing group as shown in Scheme 1[6]. We have been interested in generation and accumulation of cations of other elements such as silicon