Study On Oxidation Reaction Of Thioethers Via Cyclic Diacyl Peroxides

Sulfoxides which are widely applied in the search of biologically drugs and organic chemistry, have attracted considerable attention of researchers in different fields. Several sulfoxides can serve as conventional medicines, such as omeprazole for stomach disease, modafinil for neurological disease, and sulfinpyrazone for cardiovas cular disease. In addition, the chiral sulfoxides also can be used as chiral auxiliaries, chiral ligands and chiral catalysts with extensive use in asymmetric synthesis.The oxidation of thioethers provides an approach for preparing the sulfoxides most directly. Recently, cyclic diacyl peroxide as a mild oxidant has been used in the dihydroxylation of olefins and oxidation of carbon-hydrogen bonds. In this dissertation, a selective oxidation of thioethers to sulfoxides based on the cyclic diacyl acyl peroxide as oxidant has been explored, and the oxidative mechanism has been discussed as well.In this dissertation, two kinds of cyclic diacyl peroxides, namely the phthaloyl peroxide(PPO) and cyclopentyl malonyl peroxide(MPO), have been synthesized. we mainly investigated the oxidation of thirty seven thioethers to sulfoxides with good functional group tolerance, which provided high yields and high selectivities. Subsequently, the scope for sulfides with diverse functional groups was examined further. In addition, MPO also showed an excellent oxidative performance under a mild reaction condition with a high yield in the synthesis of omeprazole.With the density functional theory calculation and the determination by gas chromatography-mass spectrometry and nuclear magnetic resonance, the oxidative mechanism of cyclic diacyl peroxide was discussed, and the plausible reaction mechanism was proposed.With utilizing the cyclic diacyl peroxides as oxidant, the conversion of sulfoxides into sulfoxides has the advantages: a simple operation without adding other catalysts and additives; a mild oxidative performance of selective oxidation of sulfides to sulfoxides; a large substrate scope with highly functional group tolerance.