Anomeric Hydroperoxides; Synthesis, Enantioselective Epoxidation
نویسندگان
چکیده
Some time ago we reported the oxidation of 2,3-unsaturated hexopyranosides and 2-Cmethylene glycosides with hydrogen peroxide in the presence of molybdenum trioxide catalyst to give the corresponding anomeric hydroperoxides 1-5. Relatively stable hydroperoxides 1-5 were used for enantioselective oxidation of prochiral alcohols and sulfides in the presence of Ti(OiPr)4 with stereoselectivities varied from about 10 to 50 e.e. They have, however, several significant drawbacks such as the accessibility, relatively low asymmetric induction and they can not be regenerated to be used again after reoxidation. Epoxidation of electrophilic olefins with anomeric hydroperoxides in the presence of a base in principle does not remove drawbacks of the reagents mentioned above.
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