Organic Azides : Functional Molecules and Materials
Sammanfattning: The work presented in this thesis stems from the chemistry of the azido group, and more specifically from the unique reactivity of perfluorinated aromatic azides and how to use this reactivity to access new types of molecules to enable new applications in asymmetric synthesis and materials.In the first section of this thesis, a photoactivatable fluorescence probe is presented, where the non-luminescent azide was activated via a UV-light-promoted intramolecular N–H insertion reaction forming a fluorescence emitter. Furthermore, ciprofloxacin was reacted with perfluorinated aromatic azide (PFAA) and phenylacetaldehyde, to form a drug derivative with a propeller-shaped architecture. The drug derivatization enabled the self-aggregation of the molecules into nanoparticles and the consequent aggregation-induced fluorescence emission (AIE). The second section of the thesis focuses on the development of a reaction between the photogenerated perfluorinated phenylnitrene and sulfoxides or sulfinamides to obtain sulfoximines and sulfonimidamides. One of these compounds, an enantiopure sulfonimidamide with an unprotected amino group, was employed as a novel chiral auxiliary for the synthesis of an enantioenriched amine via addition of Grignard reagents to the formed imines. In addition to the use as chiral auxiliary, the same sulfonimidamide containing a pyridine group was studied as an organogelator. The supramolecular aggregation led to the formation of the gel, which showed a microscopic chirality controlled by the stereocenter of the sulfur atom in the low-molecular weight gelator molecule. The last section illustrates a general method for the reduction of aromatic and aliphatic azides. The reduction is catalyzed by a nickel boride (Ni-B) catalyst that is prepared in situ from a Ni(II) salt and sodium borohydride in methanol allowing catalyst loading as low as 0.5 mol%. Moreover, bacterial nanocellulose (BNC) was used as solid support for the Ni-B catalyst enabling easy recovery of the catalyst and recyclability.
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