Mild and Highly Chemoselective Oxidation of Thioethers Mediated by Sc(OTf)₃

Abstract

[reaction: see text] Catalytic Sc(OTf)(3) greatly increases the efficiency of hydrogen peroxide mediated monooxidation of alkyl-aryl sulfides and methyl cysteine containing peptides. The method is high yielding, compatible with many widely used protecting groups, suitable for solid-phase applications and proceeds with minimum over-oxidation.

Modular Asymmetric Synthesis of Pochonin C

“…[19] Chemoselective oxidation of the thioether with H 2 O 2 in hexafluoropropan-2-ol [20] led to clean conversion into the thiosulfoxide with no overoxidation product or epoxide opening, as had been observed with meta-chloroperoxybenzoic acid or H 2 O 2 / ScOTf 3 (Tf = trifluoromethanesulfonyl). [21] Interestingly, elimination of the sulfoxide proceeded only for the compound leading to the desired trans,cis diene 14. Presumably, the trans olefin 16 cannot adopt an adequate conformation to participate in a 1,2-syn elimination of the sulfoxide group.…”

Selective, metal-free oxidation of sulfides to sulfoxides Using 30% hydrogen peroxide catalyzed with N-bromosuccinimide (NBS) under neutral buffered reaction conditions

“…On the other hand, in all of the studied oxidation reactions, no pummerer by-product was observed in any oxidation reactions. Although, formation of sulfoxides form diary1 sulfides is difficult to achieve by standard oxidation procedures using 30% H 20 2 [20][21][22][23], under the described reaction conditions, even highly hindered sulfides furnished the corresponding sulfoxide in good yields (Table 1, …”

“…In this way, *Corresponding Author. E-mail: karimi@iasbs.ac.ir various types of metal-, and non-metal-catalyzed oxidation of sulfides using clean and cheap oxidants such as H 2 0 2 [20][21][22][23][24][25][26][27], and O 2 [28][29][30][31], have been developed. Although, many of these methods are quite useful, there still remains much room for improvements especially in the case of the selectivity of the reactions.…”

Chromium (III) Catalyzed Selective Oxidation of Sulfides to Sulfoxides Using 30% H2O2

“…Whereas, if it is soluble in aqueous medium, the separation becomes convenient leaving behind catalyst in aqueous phase, which can be recycled. Various reports are available on metal catalyzed transformation of sulfide with H 2 O 2 [23][24]. But in many of these methods, metal catalyst cannot be recycled, so generation of heavy metal lost is occurred.…”