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Inner-Bond Cleavage of Sterically Congested Dibenzo[g,p]chrysene to a Rigid Figure-Eight Macrocycle
Joe Kambara1, Taito Moribe1, Tomoyuki Ikai1
1Department of Molecular and Macromolecular Chemistry, Graduate School of Engineering, and Integrated Research Consortium on Chemical Science (IRCCS), Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi 464-8603, Japan.
Abstract:
Ruthenium-catalyzed oxidative inner-bond cleavage of 1,8,9,16-tetramethyldibenzo[g,p]chrysene with four methyl groups at the sterically congested bay regions afforded 4,13,17,26-tetramethylcyclobisbiphenylenecarbonyl in an excellent yield. In this figure-eight cyclic diketone, the methyl groups at the ortho positions of the biaryl subunits enhance structural rigidity, resulting in its robust chirality and enhanced emission in its π-extended derivatives. In addition, methyl substitution provides synthetic advantages by shortening the bond-cleavage step and enabling regioselective C-H borylation.
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