《有機(jī)合成氧化》ppt課件(文件)
【正文】 ation Mild oxidizing regent for converting alcohols or aldehydes to ketones under neutral condition. Example Oxidation with oxammonium salt This regent is patible for the mild oxidation of many alcohols, including alipharic primary and secondary as well as allylic and benzylic alcohol. One group disconnections CM eM e C NO HM eM eOCM eM eC NO HN a C NH +Example CP hM eO HC C HH C C HN aL i q u i d N H 3P hM eOH C C CP hM eO HC C HExample P hP hO HP hP hO HC O 2 E t2 P h M g B r+C O 2 E t+C O 2 E tExample B r+O HO Ho rH C C H1 . N a , L i q u i d , N H 32 . a c e t o n eO HH 2 , P d CB a S O 4O HH B rB rExample OO1 . B a s e , C H 2 O2 . B a s e , C H 2 OH OH OH 2 P d CB a S O 4H OO HA c e t o n eH+OO1. Epoxides from halohydrins Halohydrins can be synthesized by the reaction of alkenes and hypohalous. Subsequent treatment of with a base such as sodium hydride generates the alkoxide, which is anti to the adjacent bromine. 2. Peroxides induced epoxidations ?Hydrogen peroxide ?Alkyl hydroperoxides ?Organic peroxyacids Hydrogen peroxide Solvent: Water or water miscible solvents Metal catalysts: V2O5, WO3, MoO3H The hydroxyl moiety can be faster than the oxidation of alkene moiety. 。 and PCC or PDC give poor yields to some oxidation reactions (hindered alcohols). DMSO with mild base leads to removal of appropriate hydrogen and expulsion of DMS generates ketones and aldehydes from alcohols. Modification of DMSO oxidation: Swern oxidation Swern found that DMSO can be activated for the oxidation of alcohols by addition of trifluoroacetic anhydride. The reaction is usually done in dichloromethane at temperat
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