Parikh-Doering Oxidation
The Parikh-Doering reaction is the oxidation of primary and secondary alcohols into aldehydes and ketones. The procedure uses dimethyl sulfoxide (DMSO) as the oxidant, activated by the sulfur trioxide pyridine complex in the presence of triethylamine base.
Parikh-Doering Oxidation
Reaction Mechanism
1. Activation of DMSO with sulfur trioxide. 2. Nucleophilic attack by the alcohol. 3. Deprotonation of the alkoxysulfonium ion gives the sulfur ylide. 4. The ylide delivers the corresponding ketone and dimethyl sulfide upon rearrangement through a five-membered ring transition state.
Experimental Procedure
The alcohol (5.63 mmol, 1.0 eq) and iPr2NEt (7.14 eq) were dissolved in anhydrous DCM (50 mL). The resulting solution was cooled to 0 °C, and sulfur trioxide-pyridine complex (SO3·py, 4.02 eq) was added. Anhydrous DMSO (14.0 eq) was added dropwise over 25 minutes. The suspension was stirred for additional 30 minutes at 0 °C. The resultant pale yellow solution was poured into brine and extracted with DCM. The combined organic layers were washed with brine, dried over MgSO4, filtered, and the volatiles removed under reduced pressure. The crude solid was purified by flash column chromatography to deliver the aldehyde (84% yield).
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