The reaction of unsymmetrical monophenyl cyclic 1,4-diazadienes with ketene derivatives yields new structures via 1,5-sigmatropic reactions. These structures were determined and confirmed by single-crystal X-ray analysis. The reaction mechanism was investigated by density functional theory calculations. The result of the calculation indicated whether the reaction was a cyclization reaction or a 1,5-shift rearrangement based on the stability of the intermediate conformation.

中文翻译：

---

环状1,4-二氮杂二烯与酮的逐步反应：特征与机理

非对称单苯基环1,4-二氮杂二烯与乙烯酮衍生物的反应通过1,5-σ反应生成新结构。通过单晶X射线分析确定并确认了这些结构。通过密度泛函理论计算研究了反应机理。计算结果表明该反应是环化反应还是基于中间构象的稳定性的1，5-移位重排。