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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.
The cyclic compound borepin has been isolated and is aromatic. Boron-boron multiple bonds are rare, although doubly-bonded dianions have been known since the 1990s. [20] Neutral analogues use NHC adducts, such as the following diborane(2) derivative: [21] [22] Each boron atom has an attached proton and is coordinated to a NHC carbene. [23] [24]
Aromatic compounds are subject to electrophilic halogenation: R−C 6 H 5 + X 2 → HX + R−C 6 H 4 −X. This kind of reaction typically works well for chlorine and bromine. Often a Lewis acidic catalyst is used, such as ferric chloride. [7] Many detailed procedures are available.
A further example of insertion into a closo carborane is the synthesis of the yellow-orange solid closo-1,2,3-(CO) 3 FeC 2 B 4 H 6: closo−C 2 B 4 H 8 + Fe 2 (CO) 9 → closo−(CO) 3 FeC 2 B 4 H 6 + Fe(CO) 5 + CO. A closely related reaction involves the capping of an anionic nido carborane C 2 B 4 H − 7. closo−C 2 B 4 H 8 + NaH → Na ...
For example, an acyl halide can react with: water, to form a carboxylic acid. This hydrolysis is the most heavily exploited reaction for acyl halides as it occurs in the industrial synthesis of acetic acid. an alcohol to form an ester; an amine to form an amide; an aromatic compound, using a Lewis acid catalyst such as AlCl 3, to form an ...
The icosahedral charge-neutral closo-carboranes, 1,2-, 1,7-, and 1,12- C 2 B 10 H 12 (informally ortho-, meta-, and para-carborane) are particularly stable and are commercially available. [10] [11] The ortho-carborane forms first upon the reaction of decaborane and acetylene. It converts quantitatively to the meta-carborane upon heating in an ...
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.
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.