Synthesis of Dibenzoazulene Derivatives via Pd‐Catalyzed (3+2) Alkyne Annulation of Dibenzosuberenone

• Published in: ChemCatChem 2024-12, Vol.16 (23), p.n/a
• Main Authors: Ma, Zhuangzhuang, Qin, Liyuan, Shangguan, Zhichun, Shu, Yilin, Ma, Junlong, Liang, Qi, Li, Cheng, Zhang, Guanxin, Zhang, Xi‐Sha, Duan, Zheng, Zhang, Deqing
• Format: Article
• Language: English
• Subjects: (3+2) Alkyne annulations; Absorption; Alkynes; Aromaticity; Chemical reactions; Chemical synthesis; Heptagon/pentagon pair; Organic chemistry; Tropyl radical; Tropylium cation
• ISSN: 1867-3880; 1867-3899
• DOI: 10.1002/cctc.202401310

Non‐benzenoid PAHs with pentagon/heptagon pairs have unique electronic structures and promising opto‐electronic properties. However, the construction of pentagon/heptagon pair units in these PAHs is challenging. Herein, we developed a Pd‐catalyzed (3+2) alkyne annulation reaction of heptagons, and constructed heptagon/pentagon pairs. The substrate scope is wide and the yield is good to moderate. A series of dibenzoauzlene derivatives were synthesized and their opto‐electronic properties were systematically studied by UV‐vis absorption and cyclic voltammetry. In addition, the dibenzoazulene derivative was further transformed to tropylium cation and tropyl radical, which showed bathochromic shifted absorption and switched aromaticity. Non‐benzenoid PAHs with pentagon/heptagon pairs have unique electronic structures and promising opto‐electronic properties. A Pd‐catalyzed (3+2) alkyne annulation reaction of heptagons was developed to construct heptagon/pentagon pairs. The neutral dibenzoazulene derivative was further transformed to tropylium cation and tropyl radical, which showed bathochromic shifted absorption and switched aromaticity.