Parikh–Doering_oxidation
The Parikh–Doering oxidation is an oxidation reaction that transforms primary and secondary alcohols into aldehydes and ketones, respectively.[1] The procedure uses dimethyl sulfoxide (DMSO) as the oxidant and the solvent, activated by the sulfur trioxide pyridine complex (SO3•C5H5N) in the presence of triethylamine or diisopropylethylamine as base. Dichloromethane is frequently used as a cosolvent for the reaction.
Compared to other activated DMSO oxidations, the Parikh–Doering oxidation is operationally simple: the reaction can be run at non-cryogenic temperatures, often between 0 °C and room temperature, without formation of significant amounts of methyl thiomethylether side products.[2] However, the Parikh–Doering oxidation sometimes requires a large excess of DMSO, SO3•C5H5N and/or base as well as prolonged reaction times for high conversions and yields to be obtained. The following example from the total synthesis of (–)-kumausallene by P.A. Evans and coworkers illustrates typical reaction conditions:[3]