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Ipso-substitution describes two substituents sharing the same ring position in an intermediate compound in an electrophilic aromatic substitution. Trimethylsilyl, tert-butyl, and isopropyl groups can form stable carbocations, hence are ipso directing groups. Meso-substitution refers to the substituents occupying a benzylic position.
The strength of the metal-arene interaction is weak as indicated by the long Ag-C bond lengths and the nearly unperturbed nature of the arene. [4] By metal vapor synthesis, metal atoms co-condensed with arenes react to give complexes of the type M(arene) 2. Cr(C 6 H 6) 2 can be produced by this method. [1]
Benzylic cations of chromium arene complexes are conformationally stable, and undergo only exo attack to afford S N 1 products stereospecifically, with retention of configuration. [1] Propargyl [ 1 ] and oxonium [ 1 ] cations undergo retentive substitution reactions, and even β carbocations react with a significant degree of retention.
The Sandmeyer reaction provides a method through which one can perform unique transformations on benzene, such as halogenation, cyanation, trifluoromethylation, and hydroxylation. The reaction was discovered in 1884 by Swiss chemist Traugott Sandmeyer , when he attempted to synthesize phenylacetylene from benzenediazonium chloride and copper(I ...
The metal–arene product can also add to another aryne, leading to chain-growth polymerization. Using copper(I) cyanide as the initiator to add to the first aryne yielded polymers containing up to about 100 arene units. [22] When leaving group (LG) and substituent (Y) are mutually ortho or para, only one benzyne intermediate is possible.
The Vilsmeier–Haack reaction (also called the Vilsmeier reaction) is the chemical reaction of a substituted formamide (1) with phosphorus oxychloride and an electron-rich arene (3) to produce an aryl aldehyde or ketone (5): RC(=O)NR ′ R″ + HArZ + POCl 3 + H 2 O → RC(=O)ArZ + NR ′ R″H + HCl + H 3 PO 4
In organic chemistry, aromatic sulfonation is an reaction in which a hydrogen atom on an arene is replaced by a sulfonic acid (−SO 2 OH) group. Together with nitration and chlorination, aromatic sulfonation is a widely used electrophilic aromatic substitutions. [1] Aryl sulfonic acids are used as detergents, dye, and drugs.
Both the regioselectivity—the diverse arene substitution patterns—and the speed of an electrophilic aromatic substitution are affected by the substituents already attached to the benzene ring. In terms of regioselectivity, some groups promote substitution at the ortho or para positions, whereas other groups favor substitution at the meta ...