Five‐fold‐symmetric Pentabromo‐ and Pentaiodo‐corannulenes: Useful Precursors of Heteroatom‐substituted Corannulenes

Abstract

Five‐fold‐symmetric pentabromo‐ and pentaiodo‐corannulenes were synthesized in sub‐gram scale in high yields under aerial conditions and were purified without any chromatographic separations. The obtained pentahalocorannulenes were fully characterized by NMR, MS, and X‐ray crystallography. The pentahalocorannulenes are useful precursors of five‐fold symmetric heteroatom‐substituted corannulenes that are difficult‐to‐address from known corannulene derivatives. As a representative example, pentaphosphinylated corannulene was prepared for the first time and was comprehensively characterized.

Five‐Fold Symmetric Pentaindolo‐ and Pentakis(benzoindolo)Corannulenes: Unique Structural Dynamics Derived from the Combination of Helical and Bowl Inversions

“…Synthesis: Recently,w er eported the synthesis of sympentabromo-and sym-pentaiodocorannulenes,which opened up ad oor for unprecedented corannulene derivatives. [12] Indeed, pentaphosphinylated corannulene was successfully prepared by aP d-catalyzed cross-coupling reaction from 1,3,5,7,9-pentabromocorannulene (17 a)o r1 ,3,5,7,9-pentaiodocorannulene (17 b)i n3 1% and 82 %y ields,r espectively. Before testing five-fold amination reactions of 17 a,f irst we conducted the amination reaction with monoiodocorannulene 12, [13] which afforded aminocorannulenes 13 and 15 in moderate yields (Scheme 2).…”

Transition-Metal-Catalyzed Silylation and Borylation of C–H Bonds for the Synthesis and Functionalization of Complex Molecules

“…These warped nanographenes (WNGs) display solubilities and photophysical properties that differ from those of traditional nanographenes, presumably because of differences in crystal packing. Electronic umpolung to access the corresponding pentabromo or pentaiodo derivatives from the pentaboryl corannulene has also been reported . Further regioselective borylation of these WNGs resulted in modification of the periphery. , …”

“…Electronic umpolung to access the corresponding pentabromo or pentaiodo derivatives from the pentaboryl corannulene has also been reported. 188 Further regioselective borylation of these WNGs resulted in modification of the periphery. 189,190 Whereas [5]circulenes possess a bowl-shaped topology, [6]circulenes are planar or nearly planar.…”

Non-Planar Polycyclic Aromatic Molecules Including Heterole Units

“…Recently, Tanaka and co-workers have reported pentahalogenated corannulenes as useful intermediates for heteoatom incorporated corannulene (Scheme 7b). 35 They applied copper-mediated halogenation of sympentaborylcorannulene 55 to obtain sym-pentabromocorannulene 56 and sym-pentaiodocorannulene 57 in a preparative scale. Although sym-pentachlorocorannulene has been employed for various peripheral functionalization reactions because of its facile preparation from parent corannulene in one step, 56 and 57 had been unprecedented.…”