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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.
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 ...
Electrophilic aromatic substitution (S E Ar) is an organic reaction in which an atom that is attached to an aromatic system (usually hydrogen) is replaced by an electrophile. Some of the most important electrophilic aromatic substitutions are aromatic nitration , aromatic halogenation , aromatic sulfonation , alkylation Friedel–Crafts ...
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.
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 ...
Aromatization is a chemical reaction in which an aromatic system is formed from a single nonaromatic precursor. Typically aromatization is achieved by dehydrogenation of existing cyclic compounds, illustrated by the conversion of cyclohexane into benzene. Aromatization includes the formation of heterocyclic systems.
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]
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 ...