A recyclable fluorous thiourea organocatalyst for the chemoselective oxidation of sulfides

Organocatalytic activation of hydrogen peroxide: towards green and sustainable oxidations

The advent of organocatalysis provided an additional option in every researcher's arsenal, towards the development of elegant and sustainable protocols for various organic transformations. Oxidation reactions are considered to be key in organic synthesis since oxygenated functionalities appear in many natural products. Hydrogen peroxide is categorized as a green oxidant, since its only by-product is water, offering novel opportunities for the development of green and sustainable protocols. In this review article, we intend to present recent developments in the field of the organocatalytic activation of hydrogen peroxide, providing useful insight into the applied oxidative protocols. At the same time, we will present some interesting mechanistic studies, providing information on the oxygen transfer processes.

One-pot hydrothermal synthesis of H3PW12O40 supported on zeolite imidazolate frameworks (ZIF-8): a highly efficient heterogeneous catalyst for oxidation of sulfides to sulfoxides and sulfones

The microporous, sodalite-like zeolite imidazolate framework ZIF-8 [Zn(MeIM); MeIM = 2-methylimidazole] has been selected as a host matrix for stabilization of guest H3PW12O40 (PW12) in this study. To modify ZIF-8 by H3PW12O40 (PW12), a one-pot hydrothermal synthesis strategy has been developed and used in the chemoselective oxidation of sulfides to the corresponding sulfoxides (and sulfones) in the presence of 30 % H2O2 in ethanol (and CH3CN) as solvent. Some of the advantages of our method include excellent yields, heterogeneous conditions, simplicity, compatibility with a variety of functionalities, and ease of isolation of the products. X-ray diffraction, scanning electron microscopy, energy-dispersive analysis X-ray spectroscopy, ultraviolet/visible rays, and Brunauer–Emmett–Teller have been used to characterize the samples prepared. Large-sized pores and cavities of ZIF-8 become occupied by PW12 units on modification with PW12, as shown by analysis results. This method might bring light to new opportunities in the development of high-performance polyoxometalate catalysts using rapidly growing ZIFs as supports.