Flavin-cyclodextrin catalysts

More recently, Kraus has reported the use of flavin-cyclodextrin conjugate catalyst 41 for the asymmetric oxidation of both aromatic and aliphatic methyl thioethers, using hydrogen peroxides in a phosphate buffer (Scheme 19.19) [120, 121]. 

Scheme 19.19 Oxidation of thioethers with flavin-cyclodextrin catalyst 4V...

The hydrogen peroxide-mediated oxidation of p-tolyl methyl sulfide with chiral iminium salt 20 (Figure 19.9), reported in 1993, gives a 32% ee [81]. The use of chiral flavinium salt catalysts afforded a 65% ee for the same transformation [119], More recently, Kraus has reported the use of flavin-cyclodextrin conjugate catalyst 41 for the asymmetric oxidation of both aromatic and aliphatic methyl thioethers, using hydrogen peroxides in a phosphate buffer (Scheme 19.19) [120, 121]. 

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