5—(L-盖氧基)—2(5—H)—呋喃酮与硝酮体系环加成反应的理论研究

THEORETICAL STUDIES ON THE 1,3-DIPOLAR CYCLOADDITION OF 5-(1-MENTHYLOXY)-2 (5-H)-FURANONE WITH NITRONE SYSTEM

选取模型化合物,用AMl MO方法从理论上研究了手性的5-(L-盖氧基)-2(5—H)-呋喃酮与偶极硝酮体系环加成反应的机理。优化了反应过程各驻点的几何构型,计算了反应的活化焓、活化熵和反应速率常数,结果表明,该反应为同面的协同过程,非对映专一性产物的形成估计是由于盖氧基及硝酮分子上苯取代基的空间效应所致。

The reaction mechanism of the 1,3-dipolar cycloaddition of 5-(1-menthyloxy)-2(5-H)-furanone with nitrone system has been investigated theoretically by using AMl MO method and transition state theory. The geometries of various critical points of the reaction pathway were optimized on the potential energy surface. The activation enthalpy, activation entropy and rate constant of the reaction were also calculated. The concerted supra-supra approach was found to proceed via a transition state. It seems likely that the stereospecific cycloaddition is determinde by steric effect of the substituents.