Fluorowane nitryloiminy jako unikatowe bloki budulcowe do zastosowań w syntezie organicznej

Abstract

Fluorinated organics exhibit unusual physio-chemical properties and for this reason, they have found numerous practical applications. Consequently, there is remarkable need for straightforward access to various fluoroorganics, and the development of new synthetic methods is one of major goals of modern organic synthesis. In this context, the presented PhD thesis focuses on the chemistry of little known fluorinated nitrile imines, formally derived from trifluoroacetonitrile, as building blocks for preparation of nitrogen heterocycles. In order to examine the reactivity of the title nitrilimines, they were tested towards three selected groups of reagents, namely (i) arynes (benzynes) as extremely reactive electron-rich dipolarophiles, (ii) chalcones as well as structurally related α,β-unsaturated compounds selected as model electron-deficient dipolarophiles, and (iii) amino acid esters indicated as attractive bifunctional electrophilic/nucleophilic agents. The main goal of the first project was to check whether it would be possible to apply in situ generated arynes/benzynes as suitable agents for trapping CF3-functionalized nitrile imines (also available in situ). Second project was focused on (3+2)-cycloadditions of title nitrile imines and chalcones (but also other enones). As demonstrated, the designed Huisgen reactions proceed highly regio- and diastereoselectively, and leads to 5-acyl-3-CF3-pyrazolines recognized as highly useful precursors of the respective pyrazoles. The final project of the Thesis was aimed at application of title nitrile imines in a formal stepwise (3+3)-cycloaddition reaction with natural α-amino esters to access hitherto unknown trifluoromethylated 1,2,4-triazine derivatives.