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The Buchner ring expansion reaction was first used in 1885 by Eduard Buchner and Theodor Curtius [1] [2] who prepared a carbene from ethyl diazoacetate for addition to benzene using both thermal and photochemical pathways in the synthesis of cycloheptatriene derivatives. The resulting product was a mixture of four isomeric carboxylic acids ...
The Dowd-Beckwith ring expansion reaction is also capable of adding several carbons to a ring at a time, and is a useful tool for making large rings. [11] While it proceeds through an intermediate bicycle the final cyclization and ring opening take place within the same radical reaction . [ 12 ]
Benzene ring contractions are the last two mechanisms that have been suggested, and they are currently the preferred mechanisms. These reaction mechanisms proceed through the lowest free energy transition states compared to the diradical and dyotropic mechanisms. The difference between the two ring contractions is minute however, so it has not ...
A heterocyclic compound or ring structure is a cyclic compound that has atoms of at least two different elements as members of its ring(s). [1] Heterocyclic organic chemistry is the branch of organic chemistry dealing with the synthesis, properties, and applications of organic heterocycles .
This reaction is related to several classic named reactions: The acylated reaction product can be converted into the alkylated product via a Clemmensen or a Wolff-Kishner reduction. [17] The Gattermann–Koch reaction can be used to synthesize benzaldehyde from benzene. [18] The Gatterman reaction describes arene reactions with hydrocyanic acid ...
The most common reactions of benzene involve substitution of a proton by other groups. [72] Electrophilic aromatic substitution is a general method of derivatizing benzene. Benzene is sufficiently nucleophilic that it undergoes substitution by acylium ions and alkyl carbocations to give substituted derivatives.
An alkyne trimerisation is a [2+2+2] cycloaddition reaction in which three alkyne units (C≡C) react to form a benzene ring. The reaction requires a metal catalyst. The process is of historic interest as well as being applicable to organic synthesis. [1] Being a cycloaddition reaction, it has high atom economy.
A common role for a metal centre in cycloaddition reactions is to exert control over the conformation of the reactants. Metal ions are frequently a component of 1,3-dipolar cycloadditions, and Diels-Alder reactions. A Lewis acidic can coerce a Diene into the reactive cisoid conformation, thereby catalyzing the reaction the Diels-Alder reaction ...