Thiophene-fused bisdehydro[12]annulene that undergoes transannular alkyne cycloaddition by either light or heat.
A new bisdehydro[12]annulene derivative having a thiophene-fused structure has been synthesized. This highly twisted π-conjugated macrocycle with two acetylene moieties in close proximity produces a [2+2]-type alkyne cycloadduct by either photoirradiation or mild heating without any transition metals. Theoretical calculations reveal that the thermal reaction proceeds through successive 8π and 4π electrocyclic reactions, while the photochemical reaction is an asynchronous concerted [2+2] cycloaddition. The fused structure with the less-aromatic thiophene ring is crucial for achieving this reaction. The cycloadduct, thiophene-fused biphenylene, has significant potential as a new polycyclic π-scaffold for electronic applications.
Department of Chemistry, Graduate School of Science, Nagoya University, Furo, Chikusa, Nagoya 464-8602, Japan. aiko@chem.nagoya-u.ac.jp
Aiko
A
Fukazawa
Hiroya
H
Oshima
Yoshihito
Y
Shiota
Shouya
S
Takahashi
Kazunari
K
Yoshizawa
Shigehiro
S
Yamaguchi
D000480:Alkynes / Q000138:chemical synthesis* / Q000737:chemistry*; D018360:Crystallography, X-Ray; D003500:Cyclization; D006576:Heterocyclic Compounds, 4 or More Rings / Q000138:chemical synthesis* / Q000737:chemistry; D006358:Hot Temperature; D008027:Light; D008958:Models, Molecular; D015394:Molecular Structure; D011789:Quantum Theory; D013876:Thiophenes / Q000737:chemistry*
D000480:Alkynes; D006576:Heterocyclic Compounds, 4 or More Rings; D013876:Thiophenes