碳環化反應在有機化學中是非常重要的合成工具，因為許多有經濟效益的天然物或生物活性分子皆具有多環的骨架。本研究提供兩種分別以電子對與自由基進行環化的反應路徑，而這些反應的過程與結果都是前所未有的。
在第一個小節中，本研究藉由密度泛函理論研究了Conia-ene反應，發現在反應過程中，具有1,3-二羰基的反應物與Au(I)催化劑經過活化發生5-endo-dig環化加成後，由於醛基被質子活化而引發一系列的遷移反應，最後導致非Conia-ene產物的產生。
在第二小節中，本研究提供了能讓亞硝基苯應用於可形成雙環的串聯環化反應，且環境溫度只須常溫，亦不須使用任何催化劑、自由基引發劑或終止劑等。經密度泛函理論計算確認了反應路徑：1-丙二烯基-2-炔基苯與兩個亞硝基苯進行環化反應，形成六圓環和五圓環的雙環主骨架。隨後，N-O斷鍵形成雙自由基，再進行C-N加成環化，產生最終產物。
多重螺烯分子因具有龐大共軛系統以及高度扭曲的骨架，故其芳香性與旋光性特殊，為具有潛力的有機光電材料。然其光學性質會受異構化影響，且其構型眾多，因此本研究發展出一個簡單的最穩定異構物預測方法，利用將多重螺烯拆解成雙螺烯並分析其螺旋構型，便能以最小的計算量獲得異構物相對能量。

Carbon ring-closing reactions play a crucial role in organic chemistry as they are utilized to synthesize many economically valuable natural products and biologically active molecules with multicyclic frameworks. This study introduces two unprecedented reaction pathways involving electron pairs and free radicals for the purpose of ring closure.
In the first section, the Conia-ene reaction was investigated using density functional theory. It was observed that under the influence of an Au(I) catalyst, the reactant containing 1,3-dicarbonyl functionality exhibited 5-endo-dig cyclization. The activation of the aldehyde group by a proton initiated a series of migration reactions, eventually resulting in the formation of non-Conia-ene products.
The second section presents a novel cascade cyclization reaction employing nitrobenzene, capable of forming a bicyclic structure at room temperature without the need for catalysts, radical initiators, or terminators. The reaction pathway was confirmed through density functional theory calculations: 1-allenyl-2-alkynylbenzene underwent cyclization with two nitrobenzenes, leading to the formation of a bicyclic framework comprising a six-membered and a five-membered ring. Subsequently, N-O bond cleavage generated double radicals, followed by C-N addition and cyclization, ultimately yielding the final product.
Multiple helicenes, characterized by extensive conjugated systems and highly twisted frameworks, exhibit distinctive aromatic and chiral properties, making them promising materials for optical or electronic divices. However, their optical properties are affected by isomerization, and they can have various conformations. Therefore, this study developed a simple method to predict the most stable diastereomer. By decomposing multiple helicenes into double helicene units and analyzing their helical configurations, the relative energies of the diastereomers can be determined with minimal computational effort.

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