Copper-Mediated Vinylic and Benzylic Fluoroalkylations and Stereoselective Synthesis of 2-Trifluoromethylglycosides

Identifier:  TDX:2651

Handle: https://hdl.handle.net/20.500.11797/TDX2651

Authors:  Mestre Ventura, Jordi

Abstract:
Over the last years, fluorine chemistry has attracted the attention of synthetic, medicinal and agrochemical chemistry. Many advances have flourished the field with new methodologies for the incorporation of trifluoromethyl and pentafluoroethyl (CF3 and C2F5) motifs, however, most of these protocols have been applied to simple molecules, mainly aryl halides. In this context, we have developed new methodologies to introduce such modifications into electron-rich alkenes. These moieties are present in biologically active structures, displaying certain degree of complexity and bearing different functional groups in its structure, for instance, glycals, heterocylcic benzoderivatives, nucleosides and nitrogeneous bases. On the other hand, it has also been explored the pentafluoroethylation of benzylic and allylic halides and the mechanism operating in this transformation. The preparation of trifluoromethylated glycals enabled their derivatization to suitable glycosyl donors to study the stereoselectivity imparted by the CF3 group in the glycosylation step, and, for accessing to 2-deoxy-2-trifluoromethylglycosides. In the context of stereoselective synthesis of deoxyglicosides, the synthesis of sarmentosyl fragment, a 2,6-dideoxyglycoside, has been achieved, giving access to the cardiac glycoside Cardenolide N-1, a natural product which displays anitumoural activity. The synthesis of this compound confirmed the proposed structure of this naturally-occurring product extracted from Nerium oleander plant.