Y. S. Li, X. Liang, W. Su
Dec 1, 2003
Citations
0
Influential Citations
11
Citations
Journal
Organic Preparations and Procedures International
Abstract
Disulfides are useful intermediates because of their use in a variety of chemical transformations.'S2 They are also important organic compounds in their own right being incorporated in molecules of biological intere~t.~ Numerous methods have been reported for the preparation of disulfides, such as the reaction of sodium disulfide with haloalkanes," the oxidation of thiols," oxidation of sodium alkyl thiosulfate by hydrogen peroxide,6 reductive coupling of sulfonyl chlorides by piperidinium tetrathiotungstate? sodium cyanoborohydride,S aluminium triiodide? etc. However, these methods are commonly used in research laboratories and cannot be applied in industry because the reagents are expensive and/or the yields are low. Triphenylphosphine is used in the stoichiometric amount on an industrial scale in the Wittig reaction to prepare compounds such as vitamin A, and is thus oxidized to triphenylphosphine oxide. Since the extremely stable triphenylphosphine oxide has only few uses, and can be disposed of only with difficulty, there have been numerous attempts to reduce it to triphenylphosphine. Direct reduction using strong reducing agents such as alanates and silanes is too costly. Although chlorination of triphenylphosphine oxide with the less costly phosgeneio gives triphenylphosphine dichloride, it is still an economically unsatisfactory process. In addition, phosgene is a highly toxic and dangerous gas and thus its transportation and storage pose considerable dangers.