Aza-helicenes are one of the most important series of heterohelicenes; herein, a series of novel aza-helicenes (5H, 6H, 6S, and 8S) were prepared via Bischler–Napieralski cyclization, and the interconversion dynamic process of these aza-helicenes was revealed using density functional theory calculations. The novel nitrogen-doped [6]helicene (6H) possesses a very high interconversion energy barrier of 36.0 kcal/mol. Two enantiomers of 6H were successfully resolved by high-performance liquid chromatography and showed desired chiral optical properties. 6H with chiral optical activity and lone electrons can be a potential candidate for chiral switches, which was demonstrated using the UV and circular dichroism spectra obtained upon titration with an acid and a base.

中文翻译：

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具有手性光学性质的氮掺杂氮杂螺旋烯的合成

氮杂-螺旋烯是最重要的杂螺旋烯系列之一；在此，通过Bischler-Napieralski环化制备了一系列新型氮杂-螺旋烯（5H、6H、6S和8S），并利用密度泛函理论计算揭示了这些氮杂-螺旋烯的相互转化动态过程。新型氮掺杂的[6]螺烯( 6H )具有36.0 kcal/mol的非常高的相互转换能垒。6H的两种对映体通过高效液相色谱法成功分离，并显示出所需的手性光学性质。6H具有手性光学活性和孤电子可以成为手性开关的潜在候选者，这通过用酸和碱滴定获得的紫外和圆二色光谱得到证明。