Study And Application Of Perfluorooctanesulfonates Titanocene /Zinc Restored Disulfides

Organic sulfur compounds, especially thiocarbonyl compounds which are important synthetic intermediates of amino acids and proteins, play an important role in the bio-sciences. Therefore, its synthesis attracts extensive attention by organic chemists and bio-scientists in recent years. Disulfides are stable and odorless substance in the air, which is an important intermediate in organic reactions. At present there are many ways to restore the disulfide, but the most of the catalysts are unstable in the water and air. Meanwhile they need the same amount of metal complex and give the product in low yield. Studies in our laboratory prove Perfluorooctanesulfonates titanocene is a kind of coordination compounds in the water and air, while zinc is a cheap and available metal. This article design a new method to restore disulfide using commercial (containing water) THF as solvent and perfluorooctane sulfonate titanocene / zinc system, and the formation of sulfur and acyl chloride,α-bromo carbonyl compounds, allyl bromide,α,β-unsaturated compound reaction are studied.Our experiments show that zinc can restored disulfide to mercaptan anion ,which reacts with acyl chloride to produce thioester using catalytic amount of Perfluorooctanesulfonates titanocene and commercial (containing water) THF as the solvent,and the yield is from 79 to 89%. As follow, we explore the subsequent reduction of the product reduced from disulfide using Perfluorooctanesulfonates titanocene and commercial (containing water) THF withα-bromo carbonyl compound reacted, and obtained a series ofα-thio-carbonyl compounds. The yield is 78-90%. Then we studied the reduction product with allyl bromide and the experiment can still be very good yield from75-87%.In view of previous studies, we explored the reduction of the disulfide and theα,β-unsaturated compounds, conjugate addition. A series ofβ-thio-carbonyl compounds are synthesized,and the yield is 71-92%. Although this reaction need zinc the same amount of perfluorooctane sulfonate titanocene, it can use the commercial (containing water) THF as the solvent. Therefor it has great scientific potential. In this paper, the reaction mechanism, the amount of perfluorooctane sulfonate titanocene titanium and zinc and the effect of reaction temperature on the yield were discussed. Because of the mild reaction conditions, simple experiment, the product of a single, easy separation of catalyst from product, no use of toxic, odor and other corrosive chemicals, for the synthese of thio ester,α-thio compounds, allyl aryl sulfide,β-thio-carbonyl compounds,our research provides a new and effective synthetic method.