Oxidation of Alkenes and Sulfides with Transition Metal Catalysts

Abstract

Abstract Alkenes and sulfides were oxidized with transition‐metal catalysts. The oxidant sources include molecular dioxygen, air and iodosylbenzene. The metal ions Mn(III), Fe(III), Co(II) and Ni(II) were used. The Catalysts 1‐18 of 1,3‐dioxo‐, β‐ketoimine‐ or salen‐types were prepared and their efficacy was examined. 1,2‐Dihydronaphthalene is most efficiently epoxidized with O 2 /Me 2 CHCHO or PhIO in the presence of Mn(III)‐salen catalysts. The Ni(II)‐, Co(II)‐ and Fe(III)‐catalysts of either β‐ketoimine‐ or salen‐types are useful for epoxidation of styrene, ( E )‐stilbene and ( E )‐benzalacetone in the O 2 /Me 2 HCHO system; these epoxidations are stereospecific without formation of corresponding diastereomeric epoxides. Oxidation of methyl p ‐tolyl sulfide with O 2 /Me 2 CHCHO is facilitated by the 1,3‐dioxo‐catalyst Co(II)‐1. Monooxidation is achieved with Me 2 CHCHO in equimolar proportions to give the corresponding sulfoxide, whereas overoxidation is realized with excess Me 2 CHCHO to give the sulfone. These epoxidation and sulfide oxidations all occur at 25 °C and are complete in less than a day.