|
The Cope reaction or Cope elimination, developed by Arthur C. Cope, is an elimination reaction of the N-oxide of a tertiary amine to form an alkene and a hydroxylamine. The reaction mechanism involves an intramolecular 5-membered cyclic transition state, leading to a ''syn'' elimination product, an Ei pathway. This organic reaction gives the same result as the Hofmann elimination, but the base is a part of the leaving group. The amine oxide is prepared by oxidation of the corresponding amine with an oxidant such as ''m''CPBA. The actual elimination just requires heat. : An application is a synthesis of methylenecyclohexane: : Piperidines are resistant to an intramolecular Cope reaction 〔''Amine Oxides. VIII. Medium-sized Cyclic Olefins from Amine Oxides and Quaternary Ammonium Hydroxides'' Arthur C. Cope, Engelbert Ciganek, Charles F. Howell, Edward E. Schweizer J. Am. Chem. Soc., 1960, 82 (17), pp 4663–4669 〕〔''Amine Oxides. VII. The Thermal Decomposition of the N-Oxides of N-Methylazacycloalkanes'' Arthur C. Cope, Norman A. LeBel; J. Am. Chem. Soc.; 1960; 82(17); 4656-4662. 〕 but with pyrrolidine and with rings of size 7 and larger, the reaction product is an unsaturated hydroxyl amine. This result is consistent with the 5-membered cyclic transition state. : == References == 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Cope reaction」の詳細全文を読む スポンサード リンク
|