The chemistry of bisallenes

• Henning Hopf and
• Georgios Markopoulos

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

Rh(III)-catalyzed directed C–H bond amidation of ferrocenes with isocyanates

• Satoshi Takebayashi,
• Tsubasa Shizuno,
• Takashi Otani and
• Takanori Shibata

Beilstein J. Org. Chem. 2012, 8, 1844–1848, doi:10.3762/bjoc.8.212

• ]. Planar chiral 1,2-disubstituted ferrocene derivatives are usually synthesized by using diastereoselective ortho-lithiation of monosubstituted ferrocenes with an appropriate chiral ortho-directing substituent such as chiral amines, sulfoxides, and oxazolines [3]. However, this method suffers from low atom

Binding of group 15 and group 16 oxides by a concave host containing an isophthalamide unit

• Jens Eckelmann,
• Vittorio Saggiomo,
• Svenja Fischmann and
• Ulrich Lüning

Beilstein J. Org. Chem. 2012, 8, 11–17, doi:10.3762/bjoc.8.2

• the magnitude of the CIS need not be correlated with the binding constants. However, when sulfoxides were added as neutral guests, the relative binding of these guests by 1 and 2 showed drastic differences. Dimethyl sulfoxide (DMSO), methylphenyl sulfoxide (MPSO) and diphenyl sulfoxides (DPSO) induced

• sulfoxides were chosen as guests, namely pyridine-N-oxide (PyNO) [18][19] and triphenylphosphine oxide (TPPO). PyNO showed the same behaviour as DMSO, i.e., large CIS for concave host 1, and small CIS for the linear compound (Figure 2, PyNO, endo-CH, 0.34 ppm for 1 and 0.14 ppm for 2). In contrast, with TPPO

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

• 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

• 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

• sulfoxides and sulfones are not described in the literature. The action of one mole of hydrogen peroxide on thioether 3 in acetic acid at room temperature for 2.5 h selectively gives sulfoxide 6 (85% yield, Scheme 3). Raising the temperature to the boiling point of acetic acid (118 °C) and using an excess of

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

• classes of organic sulfur compounds, with chirality residing at sulfur, at carbon, or at both [2][3][4][5][6][7][8]. This field of asymmetric organosulfur chemistry is particularly well developed in connection with sulfur(IV) and sulfur(VI) species with chirality at sulfur – namely sulfoxides, sulfinates

• , 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 3-substituted-1,5-dibromopentanes as precursors to heteracyclohexanes

• Bryan Ringstrand,
• Martin Oltmanns,
• Jeffrey A. Batt,
• Aleksandra Jankowiak,
• Richard P. Denicola and
• Piotr Kaszynski

Beilstein J. Org. Chem. 2011, 7, 386–393, doi:10.3762/bjoc.7.49

• been used as structural elements of liquid crystals [1][2][3][4][5][6] as well as antithrombotic and neuroprotectant agents [7][8]. Some thianes IV are found in petroleum distillates [9] and several have been used for the preparation of sulfones [7][10][11], sulfoxides [11][12], and sulfonium

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

• other heavy metal fluorides, and even by silver tetrafluoroborate under mild conditions. The halex-method allows the selective preparation of α,α-difluoroalkyl aryl sulfides (and also ethers, sulfoxides and sulfones) as intermediate products in the synthesis of herbicides [66][67]. Interestingly, the

Recent advances in carbocupration of α-heterosubstituted alkynes

• Ahmad Basheer and
• Ilan Marek

Beilstein J. Org. Chem. 2010, 6, No. 77, doi:10.3762/bjoc.6.77

• species that can react with a large variety of electrophiles (Scheme 18) [36]. The regio- and stereospecific carbocupration of higher oxidation states of sulfur (i.e. sulfoxides 35) with organocopper derivatives (R2Cu•MgX2 or R2Cu•LiX) rapidly provides the corresponding metalated β,β-dialkylated ethylenic

• sulfoxides 36 in quantitative yields (Scheme 19) [37][38][39][40] that can be further used in organic synthesis [41][42][43]. However, to obtain functionalized dialkylated ethylenic sulfoxide species, the addition of functionalized organozinc species is required. Upon treatment with (FG-R2)2Zn (2 equiv) or

• -isomers. This effect can even be reinforced when an additional chelating unit is present (pyridylSi, phosphonates, sulfoxides, sulfones, sulfoximines). The resulting vinyl copper species can react with a large variety of electrophiles leading to functionalized adducts in a straightforward manner that can

Shelf-stable electrophilic trifluoromethylating reagents: A brief historical perspective

• Norio Shibata,
• Andrej Matsnev and
• Dominique Cahard

Beilstein J. Org. Chem. 2010, 6, No. 65, doi:10.3762/bjoc.6.65

• (or selenides) with m-chloroperbenzoic acid followed by cyclization of the corresponding sulfoxides (or selenoxides) either with triflic anhydride or by direct fluorination with 10% F2/N2 in the presence of one equivalent of triflic acid or HBF4 (Scheme 2). The tellurophenium salt 7 was synthesized in

Enantiospecific synthesis of [2.2]paracyclophane- 4-thiol and derivatives

• Gareth J. Rowlands and
• Richard J. Seacome

Beilstein J. Org. Chem. 2009, 5, No. 9, doi:10.3762/bjoc.5.9

• of enantiomerically pure 4-hydroxy[2.2]paracyclophane or application of our own sulfoxide-metal exchange protocol [31] would permit enantiospecific variants of either route, but neither has been reported. An elegant entry to a variety of racemic alkyl sulfides and sulfoxides by an SEAr reaction

• developing a ‘tool-box’ for the synthesis of enantiomerically enriched [2.2]paracyclophane derivatives based on the chemistry of [2.2]paracyclophane sulfoxides [15][31][32][33]. This methodology has allowed us to develop routes to enantiomerically pure 4-monosubstituted [2.2]paracyclophanes [31] along with a

Synthesis of methylenebisamides using CC- or DCMT- activated DMSO

• Qiang Wang,
• Lili Sun,
• Yu Jiang and
• Chunbao Li

Beilstein J. Org. Chem. 2008, 4, No. 51, doi:10.3762/bjoc.4.51

• amides can be aromatic or aliphatic. The operation is simple and the reagents are inexpensive. Keywords: amides; condensation; DMSO; methylenebisamides; 2,4,6-trichloro[1,3,5]triazine; Introduction Sulfoxides are activated by electrophiles to produce reactive sulfonium salts. These electrophiles

• ], hexamethylenetetramine [21] or activated DMSO [6], or by the reaction of nitriles with formaldehyde [22] or activated sulfoxides [23]. However, each method has certain limitations with regards to scope and reaction conditions, for example, longer reaction time [20], lower yield [6], purification problems [21][23] and

Asymmetric synthesis of biaryl atropisomers by dynamic resolution on condensation of biaryl aldehydes with (−)-ephedrine or a proline- derived diamine

• Ann Bracegirdle,
• Jonathan Clayden and
• Lai Wah Lai

Beilstein J. Org. Chem. 2008, 4, No. 47, doi:10.3762/bjoc.4.47

• imidazolidines [25][27], ephedrine-derived oxazolidines [26][27], and, most extensively, sulfoxides [16][29][30][31]. These perform well when a powerful electronic or steric bias is evident about the atropisomeric bond over which control is applied [32], and in the case of atropisomeric amides have offered

The use of chiral lithium amides in the desymmetrisation of N-trialkylsilyl dimethyl sulfoximines

• Matthew J. McGrath and
• Carsten Bolm

Beilstein J. Org. Chem. 2007, 3, No. 33, doi:10.1186/1860-5397-3-33

• aryl-alkylsulfoximines are generally prepared by resolution with camphorsulfonic acid but this method is not applicable to dialkyl sulfoximines. [5][6][7] Imination of enantioenriched sulfoxides and derivatisation of sulfoximines with enantiomerically pure amino acid derivatives also provide

• enantioenriched S-chiral sulfoximines but both methods lack generality due to the limited availability of the appropriate chiral sulfoxides and the limited scope for cleavage of the chiral auxiliary in the latter process. [6][7][8][9][10][11][12][13][14][15] Selective substitution of one of the enantiotopic

• TMSCl quenching when sulfoximine 1b was first lithiated by treatment with n-BuLi followed by addition of a solution of (S,S)-bis-N,N-(1-phenylethyl)amine and lithium chloride (Scheme 5). In an analogous reaction, enantioenriched lithiated sulfoxides racemised via a reversible disproportionation to the