Introduction
<P>Benzyltriphenylphosphonium peroxymonosulfate (
1, BTPPMS) is a mild, efficient,
stable, and cheap reagent which displays its versatility in organic
synthesis. It is a white solid and generally stored at room temperature.
It is quite soluble in dichloromethane, chloroform, acetone, and
acetonitrile but insoluble in non-polar solvents, such as carbon
tetrachloride,
n-hexane, and diethyl
ether. It has been used for the oxidation of alcohols to aldehydes
and ketones under aprotic solvent condition,
[
¹]
oxidative
deprotection of trimethylsilyl and tetrahydropyranyl ethers under
non-aqueous conditions,
[
²]
and
selective oxidation of sulfides and thiols to the corresponding
sulfoxides and disulfides under solvent-free conditions.
[
³]
It was also found to be
useful for the dethioacetalization of 1,3-dithiolanes
and 1,3-dithianes to the corresponding carbonyl compounds in the
presence of bismuth chloride under aprotic conditions
[
4]
and conversion of oximes and semicarbazones
to carbonyl compounds using microwave irradiation to afford the
carbonyl compounds.
[
5]
Because of the mild
conditions as well as the high yields, this reagent has wide acceptance
in the area of synthetic chemistry. </P>
Preparation
<P>BTPPMS can be easily prepared
[
6]
from
commercially available reagents. To a solution of benzyltriphenylphosphonium
chloride in water a solution of Oxone
® in water was
added dropwise. After stirring for 1 h at room temperature, the
resulting precipitate was filtered, washed with cooled distilled
water and dried in a desiccator to afford a white powder which decomposed
at 144-146 ˚C. The white solid was then
titrated three times
[
7]
to yield 99% of the
active oxidizing agent (HSO
5). </P>
Scheme 1
