Abstract
Oxidation of benzyl alcohols to the corresponding aldehydes was
achieved by an acid catalyzed DMSO oxidation. When the oxidation
was catalyzed by HBr, no side products were detected. In most cases,
the yields were excellent. The oxidation rate depends on both the
nature and the position of the substituents on the aromatic rings.
A tentative mechanism is proposed for the oxidation.
Key words
oxidation - DMSO - HBr - benzyl alcohols - benzaldehydes
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9 Typical procedure: A mixture of 557
mg of benzyl alcohol, 0.15 mL of HBr (48%) and 5 mL of
DMSO was stirred in an oil bath at 100 ºC. TLC (petroleum
ether/diethyl ether, 1:1) was used to indicate the completion
of the reaction (3 h). To the reaction mixture were added 5 mL of
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ether and subsequent bulb to bulb distillation produced 530 mg of benzaldehyde
in 95% yield.
