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The efficient synthesis of dibenzo[d,d']benzo[1,2-b:4,3-b']dithiophene and
Zhihua Wang1, Sheng Zhu, Jianwu Shi
1Key Lab for Special Functional Materials of Ministry of Education, Henan University, Kaifeng 475004, China.
Abstract:
With 3,3'-bi[benzo[b]thiophenyl] as starting material, dibenzo[d,d']benzo[1,2-b:4,3-b']dithiophene, a [5]heterohelicene, was synthesized efficiently in 60% yield via formylation and McMurry reaction. Cyclopenta[1,2-b:4,3-b']bis(benzo[d]thiophen)-6-one, another interesting helical ketone, was also prepared in 79% yield via deprotonation and ketonization of 3,3'-bi[benzo[b]thiophenyl]. In addition, the single-crystal structure of dibenzo[d,d']benzo[1,2-b:4,3-b']dithiophene and UV-vis spectra of both title compounds are described.
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Structure of Conjugated Dienes
Conjugated dienes are compounds characterized by the presence of alternating double and single bonds. In a conjugated system like 1,3-butadiene, the unhybridized 2p orbital on each carbon overlaps continuously, allowing the π electrons to be delocalized across the entire molecule. In contrast, this type of overlap does not occur in cumulated and isolated dienes, such as 2,3-pentadiene and 1,4-pentadiene, respectively. Instead, the π electrons remain localized between the double...

