The thermal decomposition of an acyl azide to an isocyanate and nitrogen gas is known as the Curtius rearrangement. The R group of the acyl azide migrates to its nearest nitrogen, releasing nitrogen gas to form the isocyanate product, which can further react with nucleophiles in solution, i.e. exposure to...

Known also as the "Eschweiler-Clarke methylation", this reaction converts a 1° or 2° amine to a 3° amine in a one-pot reaction with excess aqueous formic acid and formaldehyde. An iminium ion is first formed from the starting amine and formaldehyde via an aminal intermediate. A hydride transfer from the...

The Bartoli indole synthesis uses an alkenyl Grignard reagent in excess at low temperatures and an acid work-up to convert a substituted nitroarene to an indole. The mechanism is not clear in every detail, but the main steps have been elucidated. The first equivalent of the Grignard reagent attacks the...

This Nobel Prize-winning (2010) palladium-catalyzed cross-coupling reaction between organohalides and organoboron compounds is a versatile four-step process, creating carbon-carbon sigma bonds: (i) Oxidative addition of the organohalide to the Pd(0) catalyst, creating a halide-Pd(II)-alkyl complex (ii) Replacement of the halide attached to the complex with the anion of the base...

Esters are hydrolyzed either by aqueous base or acid to yield carboxylic acids plus alcohols. In base-catalyzed hydrolysis (saponification), a hydroxide ion attacks the ester carbonyl to produce a tetrahedral alkoxide intermediate. Elimination of the alkoxide ion generates the carboxylic acid, which is immediately deprotonated by the alkoxide ion. An...

Sandmeyer Reaction A radical mechanism, catalytic for copper(I) salt has been proposed for the Sandmeyer reaction, which converts an aryldiazonium halide/salt to an aryl halide or an aryl pseudohalide. The required aryldiazonium halide is usually prepared from arylamines (via diazotization) using either NaNO2/hydrohalic acid or alkyl nitrites under anhydrous conditions....