Theoretical Study of 1,3-Dipolar Cycloaddition of Hydrazoic Acid to Substituted Ynamines

采用高精度CBS-QB3方法对一系列取代炔胺与叠氮酸之间的1,3环加成反应进行了理论研究. 该反应生成两种区域选择性异构体，它们分别是4-取代和5-取代加成物，其中以5-取代加成物为优势产物. 此区域选择性由前线分子轨道理论给出了合理解释.该反应的活性和协同性随着取代炔胺的取代基吸电子能力增加而增加. 计算结果也表明,溶剂效应使叠氮酸与取代炔胺的1,3环加成反应的活化能垒增加，在极性溶剂下，该反应变得难以进行.

Theoretical Study of 1,3-Dipolar Cycloaddition of Hydrazoic Acid to Substituted Ynamines

The 1,3-dipolar cycloaddition reactions of various substituted ynamines with hydrazoic acid were theoretically investigated with the high-accuracy CBS-QB3 method. Two regioisomers,4-amine, and 5-amine substituted adducts, were obtained, with the former as the preferred yield. This regioselectivity is rationalized by the frontier molecular orbital theory.The reactivity and synchronicity are enhanced with the increase of the electron-withdrawing character of the substitute on ynamine fragment. The calculations also show that the effect of solvent increases the activation energy, and the reaction becomes even harder in polar solvent.