Acta Chimica Sinica ›› 1992, Vol. 50 ›› Issue (8): 811-816. Previous Articles     Next Articles

Original Articles

N-烯基硝酮分子内环加成反应区域选择性的理论研究I. N-3-丁烯基硝酮分子内环加成反应的区域专一性

马思渝;傅孝愿   

  1. 北京师范大学化学系
  • 出版日期:1992-08-15 发布日期:1992-08-15

Theoretical study on the regiochemistry of intramolecular N-alkenylnitrone cycloaddition. I. the regiospecificity of intramolecular N-3-butenyl nitrone cycloaddition

MA SIYU;FU XIAOYUAN   

  • Online:1992-08-15 Published:1992-08-15

The regiospecificity of intramol. N-3-butenyl nitrone cycloaddn. has been investigated by semiempirical MO AM1 method and energy gradient technique. The calculated results show that the cycloaddn. consts of two similar parallel reactions in which the conformers (Ra and Rb) of N-3-butenyl nitrone generate the regioisomers Pa and Pb via transition states TSa and TSb resp. The geometries of these reactants, TS and products were optimized on the potential energy surface, the regiospecificity is determine by the ratio of the rate constants of the two reactions. The value is 124.1, which is in good agreement with experiments The determing factors of the rate ratio come from the joint contribution of the activation enthalpy and activation entropy.

Key words: REACTION MECHANISM, CYCLOADDITION REACTION, TRANSITION STATE THEORY

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