Role of Hexafluoro-2-propanol in Selective Oxidation of Sulfide to Sulfoxide: Efficient Preparation of Glycosyl Sulfoxides

Abstract

Aqueous 30% H2O2 in hexafluoro‐2‐propanol (HFIP) is described as a facile, selective and efficient oxidant for the conversion of sulfides to sulfoxides under neutral conditions. The nitrogen center of the pyridine molecule and the carbon–carbon double bond are shown to not be affected by the reagent system used. The oxidation of glycosyl sulfides to glycosyl sulfoxides was achieved in very high yield at room temperature.

2,5-Diketopiperazine Catalysts as Activators of Dioxygen in Oxidative Processes

“…Several substituents such as alkenes, halogens, free amino groups, and acids can also be tolerated. In all reactions, no formation of overoxidized products (sulfones) was evidenced as was expected by earlier reports of sulfide oxidation in HFIP …”

Diastereoselective Synthesis of Sulfoxide‐Functionalized N‐Heterocyclic Carbene Ruthenium Complexes: An Experimental and Computational Study

“…To circumvent this overoxidation process we used 1,1,1,3,3,3‐hexafluoro‐2‐propanol (HFIP), as described by Bégué and co‐workers [29] . The electron‐withdrawing character of the CF 3 group promotes strong hydrogen bonding leading to two different roles namely the activation of H 2 O 2 and the decrease of the nucleophilicity of sulfur atom of the sulfoxide preventing its overoxidation [29b] . This mild oxidation in neutral conditions was carried out in HFIP with 30 % aqueous H 2 O 2 at room temperature and after 10–15 min gave the corresponding alkyl sulfoxide as the sole product in good yields (70–88 %, method B , Figure 1), with the exception of the adamantyl derivative for which the formation of sulfone 3 d was still observed.…”

Pd-Catalyzed Picolinamide-Directed Late-Stage Chalcogenation of Tryptophan-Containing Peptides

“…For example, upon oxidation of 3a with 30% aqueous H 2 O 2 , the sulfoxide (5) was formed in 73% yield (Scheme 10). 32 The treatment of oxone with 3a and 4e delivered sulfones 6a and 6b, respectively, in good yields (Scheme 10). 29 Later, a gram scale reaction was conducted using 1a and 2f as model substrates (Scheme 11).…”