Studies of the properties of fluorinated biologically active molecules are becoming increasingly important due to their potential applications in medicine. Various fluorinating reagents were discovered, and consequently, methods used by the pharmaceutical industry for drug development. This work specifically deals with reactions of nucleophilic fluorination of secondary alcohols with diethylaminosulfur trifluoride (DAST), which was selected due to easy handling and in the literature described stereoselective substitution following SN2 mechanistic pathway. I used different substrates; I started with the model 4-tert-butylcyclohexanol, which produced fluoride and olefin in a ratio of 1 : 2. Cholesterol followed, and I isolated the fluorinated analogue in 60% yield. Then I used the benzyl alcohol derivatives and their fluorinated analogues proved to be unstable. I checked the (stereo)selectivity with α-hydroxy ketone compounds. It was shown that the reaction with DAST produced a mixture of enantiomers despite the expected SN2 conversion and the use of optically pure starting compounds. A racemate was formed at room temperature but at -78 °C the enantiomeric excess was 28 %. Furthermore, the yield after isolation was 90 % at -78 °C and 32 % at room temperature. Glucose derivatives followed; I isolated the fluorinated pyranose analog with 86 % yield, but the fluorination did not take place on the furanose analog. In the end, amine I have not been able to isolate a fluorinated analog of the amine (-)-ephedrine with an unprotected amine group, so I suppose that protection is necessary for the reaction with DAST. The syntheses were mainly caried out at room temperature in dichloromethane and the products were isolated and if needed, they were further purified by column chromatography. The 1H, 19F and 13C NMR spectra of the fluorinated products were measured. Other syntheses included the procedures for the preparation of corresponding secondary alcohols and were followed after literature reports.
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