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During the last decades, helicenes gained a considerableamount of attention, and not only from synthetic chemists. Their unique helical shaped backbone, which is formed by a successive annulation of (hetero)aromatic rings, has led to animpressive number of diverse applications, mostly based on the inherentlychiral conformation. Although these applications are covering several fascinating domains, like for example chiral catalysis, self-assembly and biomolecular recognition, helicenes remain limitedto the field of academic research. One of the more generally accepted reasons for this is the rather challenging synthesis of the helical skeleton, resulting in a lack of broadly applicable, large-scalepreparations. Recently however, a lot of effort has been devoted to implement transition-metal catalyzed reactions instead of the more common photocyclizations of stilbene-type molecules, the latter suffering from drawbackslike low substituent compatibility and high-dilution conditions. Within this work we have successfully explored different strategies towards the preparation of oxa-helicenes in which we avoid the use of photochemical transformations. In the first part the development of a synthetic approach towards a novel helicene framework is discussed, in which the oxidative coupling of dibenzofuran fragments and palladium catalyzed arylations play a key role. The inability of transferring this new method to more substituted moieties leads to the proposal of a second approach, in which a reversed tactic is established. A radical new procedure is suggested in the third part of this work as a result of the positive findings obtained regarding the palladium catalyzed arylations. In this part, a successful method for the construction of a novel trioxa[7]helicene framework is discussed, ultimately leading to a general applicable one-pot synthesis of highly substituted dibenzofuran fragments.In the last part some less successful approaches are discussed, as well as the preliminary study towards the formation of a new tetraoxa[9]helicene by making use of a [2+2+2] cycloisomerization. Furthermore, the use of H8-BIFOL as a chiral ligand is briefly examined in the final section of this work.

academic collection --- 544.122.3 --- Chirality --- Theses