Beiträge zur Chemie funktionalisierter a-Bromsulfone, Cyclooctine und Diazaacene
a-Bromsulfone: In der vorliegenden Arbeit wurden diastereoselektive Reaktionen zur Synthese und Funktionalisierung von a-Bromsulfonen untersucht. Aufbauend auf vorher geleistete Arbeiten konnte die diastereoselektive Reaktion von g-Hydroxydibromiden mit Sulfinaten auf neue Substrate übertragen werde...
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Table of Contents: a-Bromosulfones: In the presented work, diastereoselective reactions for synthesis and functionalization of a-bromosulfones were examined. Based on previously achieved results, the reaction of a-hydroxy dibromides with sulfinates could be transferred to new substrates. The results confirm the assumption that the diastereoselektivity depends mainly on the conformational rigidity of the gem dibromide employed. A further aim was to research the options of functionalization of a-bromosulfones. It was firstly examined if a methyl protected bromosulfone could be converted with electrophiles in a diastereoselective manner after transformation to the sulfonyl carbanion. After extensive optimization of reaction conditions the reaction could be realized with different electrophiles in very high diastereoselectivities of ≥ 10:1. The anti-product was the preferred diastereomer in all cases. Secondly, the substitution of the bromo atom in bromosulfones with nucleophiles was examined. In a copper-catalyzed reaction the substitution of the bromine atom by a methyl group was achieved. Cyclooctynes: The synthesis of alkyne functionalized cyclooctyne was successfully accomplished. This was possible in 9 linear steps with an overall yield of 13%. The synthetic route enabled the synthesis of further functionalized cyclooctynes through the early integration of a vinyl triflate. Furthermore, it was possible to do first reactions on model systems which could be helpful for the intended assembly of multi-layers on Si(001). Diazaacenes: Starting from 2,3-diaminonaphthalene three different self-complementary diazatetracenes and three diazapentacenes could be efficiently synthesized in this project. Besides synthesis, the optical and electrochemical properties of these compounds were examined as well as the molecular packing of the fluorinated compounds.