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An important synthetic application using such dialkylboranes, such as diethylborane, is the transmetallation of the organoboron compounds to form organozinc compounds. [9] [10] Some diaryl and dialkylboranes are well known. Dimesitylborane is a dimer (C 6 H 2 Me 3) 4 B 2 H 2). It reacts only slowly with simple terminal alkenes.
Halogenation of benzene where X is the halogen, catalyst represents the catalyst (if needed) and HX represents the protonated base. A few types of aromatic compounds, such as phenol, will react without a catalyst, but for typical benzene derivatives with less reactive substrates, a Lewis acid is required as a catalyst. Typical Lewis acid ...
In chemistry, halogenation is a chemical reaction which introduces one or more halogens into a chemical compound. Halide-containing compounds are pervasive, making this type of transformation important, e.g. in the production of polymers, drugs. [1] This kind of conversion is in fact so common that a comprehensive overview is challenging.
Carborane acids H(CXB 11 Y 5 Z 6) (X, Y, Z = H, Alk, F, Cl, Br, CF 3) are a class of superacids, [1] some of which are estimated to be at least one million times stronger than 100% pure sulfuric acid in terms of their Hammett acidity function values (H 0 ≤ –18) and possess computed pK a values well below –20, establishing them as some of the strongest known Brønsted acids.
These compounds all contain an atom with an unshared pair of electrons (oxygen, sulfur, or nitrogen) as a member of the aromatic ring, which substantially stabilizes the cationic intermediate. Examples of electrophilic substitutions to pyrrole are the Pictet–Spengler reaction and the Bischler–Napieralski reaction .
ArGeEt 3 can react with electrophilic halogen sources without transition-metal catalysts to give ipso halogenation product under mild conditions. [8] For the bromination (with NBS ) and iodination (with NIS ), the reaction is highly chemoselective, with halogenation solely taking place at C–Ge in presence of electron-rich arene, heterocycle ...
The medical applications of carboranes have been explored. [14] [15] C-functionalized carboranes represent a source of boron for boron neutron capture therapy. [16] The compound H(CHB 11 Cl 11) is a superacid, forming an isolable salt with protonated benzene cation, [C 6 H 7] + (benzenium cation). [17] The formula of that salt is [C 6 H 7 ...
The most commonly employed Sandmeyer reactions are the chlorination, bromination, cyanation, and hydroxylation reactions using CuCl, CuBr, CuCN, and Cu 2 O, respectively. More recently, trifluoromethylation of diazonium salts has been developed and is referred to as a 'Sandmeyer-type' reaction.