tert-Butyl Hydroperoxide Oxygenation of Organic Sulfides Catalyzed by Diruthenium(II,III) Tetracarboxylates

Abstract

Diruthenium(II,III) carboxylates Ru2(esp)2Cl (1a), [Ru2(esp)2(H2O)2]BF4 (1b), and Ru2(OAc)4Cl (2) efficiently catalyze the oxygenation of organic sulfides. As noted in a previous work, 1a is active in oxygenation of organic sulfides with tert-butyl hydroperoxide (TBHP) in CH3CN. Reported herein in detail is the oxygenation activity of 1a, 1b, and 2, with the latter being highly selective in oxo-transfer to organic sulfides using TBHP under ambient conditions. Solvent-free oxidation reactions were achieved through dissolving 1a or 1b directly into the substrate with 2 equiv of TBHP, yielding TOF up to 2056 h(-1) with 1b. Also examined are the rate dependence on both catalyst and oxidant concentration for reactions with catalysts 1a and 2. Ru2(OAc)4Cl may be kinetically saturated with TBHP; however, Ru2(esp)2Cl does not display saturation kinetics. By use of a series of para-substituted thioanisoles, linear free-energy relationships were established for both 1a and 2, where the reactivity constants (ρ) are negative and that of 1a is about half that of 2. Given these reactivity data, two plausible reaction pathways were suggested. Density functional theory (DFT) calculation for the model compound Ru2(OAc)4Cl·TBHP, with TBHP on the open axial site, revealed elongation of the O-O bond of TBHP upon coordination.

Zirconium oxide complex‐functionalized MCM‐41 nanostructure: an efficient and reusable mesoporous catalyst for oxidation of sulfides and oxidative coupling of thiols using hydrogen peroxide

“…In particular, sulfoxides are valuable synthetic intermediates for the production of a range of chemically and biologically active molecules including therapeutic agents such as anti‐ulcer, antifungal, antibacterial, anti‐atherosclerotic, antihypertensive and anti‐atherosclerotic drugs as well as psychotropic and vasodilator drugs . Omeprazole and the pesticide fipronil are two typical examples of the extensive application of these intermediates in the pharmaceutical and fine chemical industries . Likewise, disulfide bond formation is important in peptides, bioactive molecules and oil sweetening processes.…”

“…For example, oxidation of sulfides and thiols has been reported in the presence of various catalysts and using a variety of oxidants (e.g. metal oxidants, organic oxidants, peroxides, halogens and air) . Concerning green oxidants, hydrogen peroxide (H 2 O 2 ) is usually applied for the oxidation of sulfides and thiols as a cheap and environmentally friendly oxidant, because it is inexpensive and produces only water as a side product .…”

Schiff base complex of Cu immobilized on MCM-41 as reusable catalyst for efficient oxidative coupling of thiols and oxidation of sulfides using hydrogen peroxide

“…In particular, some of biologically active sulfoxides play an important role as therapeutic agents such as antifungal, antibacterial, anti-ulcer, anti-atherosclerotic, antihypertensive and as well as psychotropics and vasodilators [21,22]. Furthermore, Omeprazole and the pesticide Fipronil are two typical examples of the extensive application of these intermediates in pharmaceutical and fine chemical industries [23,24].…”

“…For these reasons, many methods have been developed over the years to find efficient these organic transformations [18][19][20][21][22][23][24][25][26][27][28][29][30][31][32]. For example, many methods have been reported in the presence of various catalysts and using different oxidant (e.g.…”

Unusual Structural Features in the Lysozyme Derivative of the Tetrakis(acetato)chloridodiruthenium(II,III) Complex

“…Early studies reported their potential as catalysts for the hydrogenation of alkenes and alkynes9a,b and for the competitive cyclopropanation of alkenes 9c. More recently, compound 1 and its derivatives have been reported to act as catalysts for the oxidative transformation of secondary amines into imines,9d the oxygenation of organic sulphides,9e the oxidation of alcohols,9f and the skeletal reorganization of enynes 9g…”