Wassy D,
Pfeifer M,
Esser B.
* University of Freiburg, Germany
Synthesis and Properties of Conjugated Nanohoops Incorporating
Dibenzo[
a,
e]pentalenes: [2]DBP[12]CPPs.
J. Org. Chem. 2019;
DOI:
10.1021/acs.joc.9b01195
Key words
conjugated nanohoops - antiaromaticity - π-system
Significance
Conjugated nanohoops have attracted attention mainly because of the extensive investigation
of cycloparaphenylenes in recently years. In their paper, Esser and co-workers synthesized
conjugated nanohoops containing dibenzo[a,e]pentalene (DBP), which is a nonalternant hydrocarbon with antiaromatic character.
With the incorporation of DBPs, the nanohoops exhibited ambipolar electrochemical
behavior.
Comment
The conjugated nanohoops containing DBPs were synthesized in six steps including a
nickel-mediated macrocyclization reaction. It is worth noting that since the DBP units
were attached to electron-withdrawing substituents in the nanohoops, the antiaromatic
character of the DBP was reduced. Furthermore, analysis showed that the frontier molecular
orbitals were separated between the CPP and DBP units in the nanohoop.
