Reciprocal polyhedra and the Euler relationship: cage hydrocarbons, C_nH_n and closo-boranes [B_xH_x]²⁻

• Michael J. McGlinchey and
• Henning Hopf

Beilstein J. Org. Chem. 2011, 7, 222–233, doi:10.3762/bjoc.7.30

• reaction to prepare the C14 diketone 60 (Scheme 11). In principle, one could incorporate bridgehead halogens as in 61 with the aim of carrying out two Favorskii ring contractions to generate the octahedrane skeleton, viz. the dicarboxylic acid 62, which ultimately would then require to be decarboxylated to

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

• not so activating for reaction with CF3SCl. For example, thiophenol [76] forms only phenyltrifluoromethyl disulfide [70]. The presence of a methyl group and halogens requires high temperatures (100–200 °C) and the presence of catalysts (HF or BF3) for reaction and yields of the corresponding

• these conditions. Thus, this method allows the selective substitution of different halogens by varying the temperature. Since the original work on trifluoromethylthiocopper and trifluoromethylthiomercury [93][95][96][101][102], other nucleophilic reagents and new methods have been developed. For example

• these reactions are illustrated in Scheme 34. This reagent can displace a range of activated halides, particularly bromides and iodides. For the reaction of 2,4-(NO2)2C6H3X with AgSCF3/KI, the reactivity of the halogens occurs in the reverse sequence: F (26%) < Cl (52%) < Br (85%) < I (97%) [118

Suzuki–Miyaura cross-coupling reaction of 1-aryltriazenes with arylboronic acids catalyzed by a recyclable polymer-supported N-heterocyclic carbene–palladium complex catalyst

• Guangming Nan,
• Fang Ren and
• Meiming Luo

Beilstein J. Org. Chem. 2010, 6, No. 70, doi:10.3762/bjoc.6.70

• biaryl products. Electron-donating groups on the 1-aryltriazenes and electron-withdrawing substituents on the arylboronic acids lead to reduced yields. Steric hindrance of ortho substituents slightly reduced the product yields (Table 5, entries 4, 7). Halogens on 1-aryltriazenes gave lower yields (Table

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

• , chemical and biological properties [3]. The specific physical and chemical properties of fluorine in fluorine containing compounds, especially its strong electronegativity, lipophilicity and reaction ability, differ dramatically from those of other halogens and thus lead to changes in the interaction

The subtle balance of weak supramolecular interactions: The hierarchy of halogen and hydrogen bonds in haloanilinium and halopyridinium salts

• Kari Raatikainen,
• Massimo Cametti and
• Kari Rissanen

Beilstein J. Org. Chem. 2010, 6, No. 4, doi:10.3762/bjoc.6.4

• due to electrostatic effects, but polarization, charge-transfer, and dispersion contributions all play an important role, more recently confirmed also by theoretical and experimental studies [8][9][10]. Interactions between halogens and nucleophilic atoms were generally considered to be too weak to be

Solvent-free phase-vanishing reactions with PTFE (Teflon^®) as a phase screen

• Kevin Pels and
• Veljko Dragojlovic

Beilstein J. Org. Chem. 2009, 5, No. 75, doi:10.3762/bjoc.5.75

• and either acrylic acid or dimethyl fumarate react at a relatively high rate [26]. As most Diels-Alder reactions are relatively slow, and most dienes are highly reactive towards halogens, it may be necessary to carry out sequential reactions. Solvent-free PV-PTFE reaction design is simple and

Chemoselective reduction of aldehydes by ruthenium trichloride and resin- bound formates

• Basudeb Basu,
• Bablee Mandal,
• Sajal Das,
• Pralay Das and
• Ashis K. Nanda

Beilstein J. Org. Chem. 2008, 4, No. 53, doi:10.3762/bjoc.4.53

• such as halogens, nitro etc. were not affected under the reaction conditions (Table 2, entries 6–11, 17). Aliphatic aldehydes (Table 2, entries 14, 15) were also reduced to corresponding alcohols efficiently. Furthermore, the presence of ortho-substituents did not hinder the rate of the reduction as

Trifluoromethyl ethers – synthesis and properties of an unusual substituent

• Frédéric R. Leroux,
• Baptiste Manteau,
• Jean-Pierre Vors and
• Sergiy Pazenok

Beilstein J. Org. Chem. 2008, 4, No. 13, doi:10.3762/bjoc.4.13

• in water more than in organic solvents (such as 1-octanol or chloroform) and hence lowers the lipophilicity [51]. It appears that the OCF3 substituent is far more lipophilic (π = +1.04) than the halogens and lies between a CF3 (π = +0.88) and a SCF3 (π = +1.44) group. It may thus replace