Electrophilic fluorinatíon of ethers and deactivated benzene derivatives

Abstract

Chapter 1 - Chapter 1 provides a literature review of the relevant topics for this thesis in organofluorine chemistry: effect of fluorine as a substituent on the molecule, synthesis of C-F bond from C-H bond using electrophilic reagents with discussions of mechanisms. Chapter 2 ― Direct fluorination of electron-rich systems such as alkyl and cyclic saturated ethers using elemental fluorine results in the formation of unexpected products: fluorinated aldal acetáis. Selectfluor™ was also used to prepare these products in good yield, but also to gain information about mechanism. Chapter 3 - Same methodology for fluorination of deactivated benzene derivatives using elemental fluorine was applied and resulted in a selective substitution of hydrogen by fluorine and allowed the synthesis of a diverse collection of polyfunctional monofluorinated aromatic products. Chapter 4 - Fluorination of 1,3- and 1,4-disubstituted benzaldehyde derivatives was studied in the reactions with elemental fluorine and resulted usually in mixtures of two products. It is concluded that the distribution of the two competing products is dependent on the total electric effect of the substituent (σ-value) attached to the aromatic ring. Chapter 5 - Our research group has developed a microreactor for the purpose of selective fluorination of a wide range of compounds such as benzaldehydes and nitrobenzenes. Low inventories of fluorine gas, in contact with reagents, provide increased safety. Optimization was obtained by varying substrate flow rate, and often resulted in a good conversion and superior yields. Chapter 6-9- Experimental details of the work discussed in Chapters 2-5.