Abstract

First and second generation of Grubbs catalysts (G1 and G2) were applied in the piperine olefin metathesis under different conditions. G1 was used in self-metathesis, G2 was implemented in both, self and cross-metathesis of piperine with eugenol. Results allowed to implicate about the main intermediate of the reaction and the position of olefin attachment to the catalyst, assuming that the reaction follows a pathway where 2A=B olefin leads to the formation of A=A and B=B. In addition, the results contributed to the studies of catalyst’s reactivity when the olefin metathesis product required the high electronic effect of the N-heterocyclic of G2. In this paper, the highest activity of G2 in the olefin metathesis of eugenol was observed when the first intermediate was Ru-eugenol-moiety in the cross-metathesis of the piperine with eugenol. This demonstrates that the acidity of the new carbene in the intermediate species causes inactivity only in the reaction with piperine.

中文翻译：

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胡椒碱复分解反应中活性中间体和烯烃附着位置的影响

摘要

第一代和第二代Grubbs催化剂（G1和G2）应用于不同条件下的胡椒碱烯烃复分解反应。G1用于自身复分解，G2用于胡椒碱与丁子香酚的自身复分解和交叉复分解。假设反应遵循 2A=B 烯烃导致 A=A 和 B=B 形成的路径，结果可以暗示反应的主要中间体以及烯烃与催化剂连接的位置。此外，该结果有助于研究当烯烃复分解产物需要G2的N-杂环的高电子效应时催化剂的反应活性。在本文中，在胡椒碱与丁子香酚的交叉复分解中，当第一个中间体为Ru-丁子香酚部分时，观察到G2在丁子香酚的烯烃复分解中具有最高的活性。这表明中间体中新卡宾的酸性仅在与胡椒碱的反应中导致不活跃。