%0 Generic
%A Popp, Dennis
%C Heidelberg
%D 2026
%F heidok:36838
%R 10.11588/heidok.00036838
%T Strategies to Circulene Precursos by Inside-out and Outside-in Shotgun Approaches
%U https://archiv.ub.uni-heidelberg.de/volltextserver/36838/
%X In the context of this thesis, two synthetic strategies towards [2n]circulenes, a class of polycyclic  aromatic hydrocarbons (PAHs) were developed, that correspond to an inside-out and outside-in approach.    For the inside-out approach, where the n-membered central ring is constructed first, a  palladium-catalyzed oligomerization of Kobayashi-aryne precursors was successfully applied to  tert-butylated pyrene. The resulting di- to pentapyrenylenes incorporated two to five [5]-helicene  moieties. Optimization of reaction parameters to increase the yield of tripyrenylene was successful and  enabled conformational investigation as well as postfunctionalization. X-ray structural analysis of the  tripyrenylene after prolonged heating confirmed the expectation of a conformational change to the chiral  D3-symmetry, which is configurationally stable, as proven by both kinetic and quantum mechanical  studies. Chiral-HPLC purification in combination with successful postfunctionalization by K-region  oxidation and -extension by aromatic ortho-diamines, lay the foundation for easy to modify  enantiopure propeller PAHs.    The inverse approach of constructing the periphery of the circulene in the beginning and closing the ring  afterwards was investigated by a Suzuki-coupling of a suitable borylated ortho-terphenylene and  ortho-halogenated veratrole building block in a 1:1 ratio. Because of this shotgun approach, an  oligomeric series of cyclo-ortho-para-phenylenes (n-COPPs) up to [40]-COPP were observed in  MALDI mass spectrometry and up to [24]-COPP isolated by elaborate purification methods involving  rec-GPC. Conformational analysis of the [n]-COPPs was possible due to variable temperature NMR  experiments and quantum mechanical studies. Subsequent cyclization by Scholl- or photocyclizations  towards the [n]circulenes generated novel PAHs. Their constitution was elucidated by thorough 2DNMR  analysis coupled with quantum mechanical studies and their optical properties were investigated.