6-羟基-1-(菲基)-哌啶-2-酮脱羟基及其阳离子环合反应机理的理论研究

Theoretical investigation on the dehydroxylation and N-acyliminium cyclization mechanisms of 6-hydroxy-l-(phenanthren)-piperidin-2-ketone

采用密度泛函理论的B3LYP方法,在6-31G*基组水平下研究了6-羟基-1-菲基-哌啶-2-酮脱羟基生成吡咯里西啶类生物碱的微观反应机理.优化了反应过程中的反应物、中间体、过渡态和产物.振动分析结果和IRC分析结果证实了中间体和过渡态的真实性.结构和能量分析表明,反应物R脱羟基并进一步发生阳离子环合反应有两条反应通道,分别为:R→IM1→TS1→IM2→P1和R→IM1→TS2→IM3→P2.反应通道R→IM1→TS1→IM2→P1控速步骤活化能最低,是该反应的主要通道.与实验报道是相吻合的.

The dehydroxylation and N-acyliminium cyclization mechanisms of 6-Hydroxy-l-（Phenanthren）- Piperidin-2-Ketone have been investigated by the DFT（density functional theory）-B3LYP method. The ge- ometries and harmonic frequencies of reactants, intermediates, transition states and products have been calcu- lated at the B3LYP/6-31G（d） level. Intermediates and transition states have been confirmed by the results of vibration analysis and the IRC calculation. Two possible pathways have been investigated, they are R→IM1→TS1→IM2→P1 and R→IM1→TS2→IM3→P2., respectively. The results indicated that the main pathway is R→IM1→1、S1→IM2→P1, which is in accordance with experimental result.