Vinyltriflimide als funktionales Chamäleon : Untersuchung der stabilisierenden Eigenschaften von Trifluoromethylsulfonyl-Substituenten in (photochemischen) Synthesen

Vinyl triflimides are a novel class of compounds that can serve as versatile building blocks in the synthesis of nitrogen-containing compounds due to their highly electron-withdrawing trifluoromethylsulfonyl groups. This dissertation investigates the reactivity and potential applications of vinyl triflimides in four projects, in which their versatility is demonstrated by means of various reactivities:1) By applying the assisted vinyl cation formation method, developed in the Niggemann working group, a stereo- and regioselective synthesis of bromovinyl triflimides was achieved, in which the nucleophilic addition to halovinyl cations is controlled and extends the previously limited synthesis possibilities of halogenated alkenes. 2) The reactivity of vinyl triflimides was investigated in photochemical processes. In triplet-triplet energy transfer reactions, they show their potential as a class of sulfonamides that undergo homolytic cleavage of the N ̶ S bond by visible light. This method overcomes the previous limitations of synthesis procedures restricted to high-energy UV light and enables the efficient one-pot two-step synthesis of α-quaternary-β-trifluoromethylated amines without the addition of external reagents due to the duality of vinyl triflimide as substrate and trifluoromethylation reagent. 3) Another photochemical approach demonstrates the versatility of vinyl triflimides in photoredox processes, in which they are reduced to trifluoromethylsulfonimines and reacted with stable boron complexes (NHC boranes) to form stable and isolable N-borylamides. These stabilized substrates overcome the problems of hydrolysis and air sensitivity encountered with compounds containing B-N bonds in traditional syntheses. 4) The stabilizing properties of trifluoromethylsulfonyl groups have also been exploited for the synthesis of imine phosphorylides, a class of compounds that has been little explored to date. Vinyl triflimides present themselves as compounds with unique properties, both in photochemical processes and in the synthesis of difficult-to-access substrate classes. A mechanistic focus of the work provides explanations for the special reactivities and possible applications of this substance class.