The Reimer-Tiemann reaction uses a dichlorocarbene precursor molecule such as chloroform, an alkali hydroxide, and a protic solvent to convert a phenol to an ortho-formyl phenol. The base first abstracts the hydrogen from chloroform, creating a trichlorocarbanion, which loses a chloride ion to form dichlorocarbene. Phenol is then deprotonated by...

In three distinct steps, the Robinson annulation converts a ketone and an α,β-unsaturated ketone into a substituted cyclohexenone compound. First, the base creates an enolate ion intermediate, which reacts with the α,β-unsaturated ketone in a conjugate 1,4 addition (Michael reaction) to form a 1,5 diketone. An intramolecular aldol reaction occurs...

The Schmidt reaction uses catalytic acid and hydrazoic acid to convert carboxylic acids, aldehydes, ketones, olefins, and 3° alcohols to amines, nitriles, amides, imines, and imines respectively. In the case of aldehydes, hydrazoic acid attacks the carbonyl group, to form a tetrahedral azidoalkanol intermediate. Water is expelled as nitrogen forms...

The synthesis of amides from amines and esters from alcohols with acyl halides or anhydrides in the presence of a base is known as the Schotten-Baumann reaction. The amine attacks the acyl halide, forming a tetrahedral intermediate that releases a halide ion. Deprotonation of the positively charged nitrogen affords the...

The Sonogashira cross-coupling reaction uses catalytic palladium, a copper(I)-salt, and a base to couple an organohalide and a terminal alkyne. The mechanism follows the expected oxidative addition-reductive elimination cycle, but the precise role of the Cu(I)-salt catalyst has not been fully elucidated. Good for small or large scale (>100g), this...

The Staudinger reaction uses a trivalent phosphorous compound such as triphenylphosphine, an organic azide, and water to make a primary amine. Triphenylphosphine first attacks the terminal nitrogen of the azide, creating a phosphazide intermediate, which undergoes a rearrangement to release nitrogen gas and form an iminophosphorane intermediate (also known as...