PDF(Pubmed)
Abstract：
The reaction mechanism of tthe formation of azomethine ylides from isatins and sarcosine is addressed in the literature in a general manner. This computational study aims to explore the mechanistic steps for this reaction in detail and to assess the reactivity of formed ylide in a 1,3-dipolar cycloaddition reaction with 7-oxabenzonorbornadiene. For this purpose, density functional theory (DFT) calculations at the M06-2X(SMD,EtOH)/6-31G(d,p) level were employed. The results indicate that CO2 elimination is the rate-determining step, the activation barrier for 1,3-dipolar cycloaddition is lower, and the formed ylide will readily react with dipolarophiles. The substitution of isatine with electron-withdrawal groups slightly decreases the activation barrier for ylide formation.
摘要：
文献中以一般方式阐述了由Isatin和肌氨酸形成甲亚胺叶立德的反应机理。这项计算研究旨在详细探索该反应的机理步骤，并评估在1,3-偶极环加成反应中形成的叶立德与7-氧杂苯并苯降冰片二烯的反应性。为此,M06-2X上的密度泛函理论(DFT)计算(SMD，EtOH)/6-31G(d,P）水平被采用。结果表明，消除CO2是速率决定步骤，1,3-偶极环加成的活化屏障较低，并且所形成的叶立德将容易地与双极化体反应。用电子撤回基团取代isatine会稍微降低叶立德形成的激活屏障。
