Reaction products and mechanism of the regioselective oxidation of N-phenylmorpholine by ozone

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• 作者：Ricardo Suarez-Bertoa ; Francesco Saliu ; Maurizio Bruschi ; Bruno Rindone
• 关键词：Ozone ; Oxidation ; N-Phenylmorpholine ; Lactam ; DFT calculations ; Reaction mechanism
• 刊名：Tetrahedron
• 出版年：2012
• 出版时间：30 September, 2012
• 年：2012
• 卷：68
• 期：39
• 页码：8267-8275
• 全文大小：855 K

文摘

The regioselective oxidation of N-phenylmorpholine by ozone in dichloromethane or acetonitrile produced a lactam and a diformylderivative. These products derive from the selective attack of ozone at the heterocyclic ring in one of the two non-equivalent reactive carbons. The reaction mechanism has been investigated by DFT calculations, which show that the reaction occurs through the insertion of ozone at the carbon-hydrogen bond of a methylene group of the morpholine ring. The regioselectivity is due to the significantly lower energy barrier calculated for the attack of ozone ¦Á to nitrogen than ¦Á to oxygen. In addition, the energy barrier decreases with increasing the polarity of the solvent, explaining the higher conversions observed for the reaction carried out in acetonitrile than in dichloromethane.