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...

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...

The Wolff-Kishner reduction uses hydrazine, a base, and a high-boiling solvent to convert an aldehyde or ketone to an alkane. The hydrazine first attacks the ketone or aldehyde, releasing water to form a hydrazone intermediate. Subsequent proton transfer steps result in the release of nitrogen gas and the formation of...

The Wolff rearrangement uses either catalytic silver oxide, heat, or light to convert an α-diazo ketone to a ketene. In a one-step reaction, the catalyst initiates a 1,2-shift to release nitrogen gas and produce ketene. Due to the release of nitrogen gas, this reaction should not be performed in a...