Kinetic investigation on the highly efficient and selective oxidation of sulfides to sulfoxides and sulfones with t-BuOOH catalyzed by La₂O₃

Abstract

The selective oxidation of various sulfides to sulfoxides by a simple, efficient, and environmentally benign method is of prime focus. In this paper, we have explored a highly efficient protocol for the oxidation of alkyl aryl sulfides to sulfoxides with high selectivities catalyzed by La 2 O 3 in the presence of 70% t-BuOOH solution (water). We obtained predominantly the monooxygenated product. The over oxidation of sulfides to sulfones was not observed under these conditions. The resulting products are obtained in good to excellent yields within a reasonable time without the use of ligands and other additives. The epoxidation of the double bond as well as allylic oxidation are not observed with allyl sulfides. Sulfones can be obtained quantitatively by altering the reaction conditions. The surface morphology and the catalyst reusability were verified by XRD, AFM and SEM techniques. The surface area of the La 2 O 3 was measured using BET isotherms.

A Concise Review on Synthesis of Sulfoxides and Sulfones with Special Reference to Oxidation of Sulfides

“…It is worthy to note that, regardless of medicinal importance of sulfones much attention has earlier been paid towards chemoselective oxidation of sulfides to sulfoxides and the protocols developed for the same have been extended towards the synthesis of sulfones. Nitric acid [122], KMnO4 [123], bromine [124], NaOCl [125], ozone [126], peracids [127][128][129], t-BuOOH [130] are few of the oxidants used in early days. Few reports are also available on the use of magnesium monoperoxyphthalate (MMPP) [131] and polyvalent [132] and hypervalent iodine compounds [133][134][135].…”

Reusable BNPs‐SiO2@(CH2)3NHSO3H‐catalysed selective oxidation of sulfides to sulfones

“…[14] Boehmite nanoparticles (BNPs) have several advantages, such as non-toxicity, ready availability, high dispersion of active phases, thermal and mechanical stability and high surface area, resulting in high catalyst loading capacity. [19][20][21][22][23][24][25][26][27][28][29][30][31] It should be noted that these procedures have some disadvantages, such as the inability for selective oxidation of sulfides, reactivity towards other functional groups, use of excess amount of oxidant with respect to substrates, lack of reusability of catalyst, use of organic solvents, low yields, expensive oxidants and harsh reaction conditions. [16,17] The derivatives of heteroaryl sulfones constitute core units of many important molecules which are used as drugs and potential precursors [18] (Figure 1).…”

“…Several homogeneous and heterogeneous oxidant-based catalytic systems have been reported for the oxidation of sulfides. [19][20][21][22][23][24][25][26][27][28][29][30][31] It should be noted that these procedures have some disadvantages, such as the inability for selective oxidation of sulfides, reactivity towards other functional groups, use of excess amount of oxidant with respect to substrates, lack of reusability of catalyst, use of organic solvents, low yields, expensive oxidants and harsh reaction conditions. [32][33][34][35] Hydrogen peroxide is an attractive and environmentally benign oxidant for the oxidation of sulfides, because it is inexpensive, easy to handle, safely stored, soluble in water and many organic solvents and produces only water as a side product.…”

Metal-free chemoselective oxidation of sulfides to sulfoxides catalyzed by immobilized l-aspartic acid and l-glutamic acid in an aqueous phase at room temperature

“…Sulfoxides, which are important building blocks or intermediates in the construction of pharmaceuticals, agrochemicals, and other valuable fine chemicals, can usually be obtained through selective oxidation of the corresponding sulfides. [1][2][3] In this extremely useful transformation, a variety of oxidants can be employed such as molecular oxygen, [4][5][6][7][8] hydrogen peroxide, [9][10][11][12][13][14][15][16] cumene hydroperoxide, [17][18][19][20] tert-butyl hydroperoxide, [21][22][23][24][25] iodobenzene diacetate, [26][27][28] sodium hypochlorite [29][30][31] and oxone. 32 Among these oxidants, aqueous hydrogen peroxide is considered as an attractive choice, which is readily available, inexpensive, safely stored, easy to operate, and environmentally benign with harmless water as the only by-product generated in the reaction.…”