The oxidation of 1° and 2° alcohols to the corresponding aldehyde or ketone, using DMSO and oxalyl chloride is known as the Swern oxidation. First DMSO is activated by oxalyl chloride, releasing CO and CO2 gas to make a chlorosulfonium salt. The alcohol then attacks the chlorosulfonium salt and deprotonation...

The Ullmann reaction uses copper metal to convert aryl halides to biaryl compounds. The mechanism is not yet fully understood, but there are two theories in consideration. The radical mechanism involves a single electron transfer (SET) to form aryl radicals that combine to produce the biaryl product. The second mechanism...

The Vilsmeier-Haack reaction or Vilsmeier-Haack formylation uses DMF, phosphoryl chloride (POCl3), and water to convert an electron-rich arene to a substituted benzaldehyde. First, DMF and phosphoryl chloride form an iminium salt called the “Vilsmeier reagent”. Then the aromatic compound attacks the Vilsmeier reagent, disturbing its aromaticity. Deprotonation by DMF restores...

The Wagner-Meerwein rearrangement uses catalytic acid to convert an alcohol into an olefin. The alcohol is protonated and released as water to form a carbocation. A [1,2]-shift of an adjacent carbon-carbon bond generates a more stable carbocation, followed by loss of a proton to afford the alkene. Both E/Z products...

The Williamson ether synthesis is an SN2 reaction The Williamson ether synthesis uses a base and an alkyl halide to convert an alcohol into a symmetrical or an unsymmetrical ether. The base deprotonates the alcohol to form an alkoxide that undergoes a nucleophilic substitution (SN2) reaction with the alkyl halide,...

The Wittig reaction uses triphenylphosphine (PPh3), a base, and a 1° or 2° alkyl halide to convert an aldehyde or ketone to an olefin. First a phosphonium salt is made when the PPh3 attacks the alkyl halide, releasing a halide ion in the process. The α-hydrogen is then deprotonated by...