Houben–Hoesch Reaction
The Houben-Hoesch reaction is an organic reaction that produces aryl ketones when nitriles react with aromatic compounds in the presence of an acid catalyst. It is a type of Friedel-Crafts acylation that uses hydrogen chloride and a Lewis acid catalyst, such as zinc chloride or aluminum trichloride. The reaction is named after Kurt Hoesch and Josef Houben, who discussed it in 1915 and 1926, respectively.
Mechanism of Houben–Hoesch Reaction
The mechanism of the reaction involves two steps. The first step is a nucleophilic addition to the nitrile with the help of a polarizing Lewis acid, forming an imine, which is later hydrolyzed during the aqueous workup to yield the final aryl ketone.