Reactions of glycerol derivatives with N,N-diethyl-1,1,2,3,3,3-hexafluoropropanamine

Abstract

Fluorination of mono- and disubstituted glycerols with N,N-diethyl-1,1,2,3,3,3-hexafluoropropanamine (PPDA) was attempted. Instead of the expected fluoroglycerol derivative from a disubstituted glycerol, the major product was the fluorinated propyl ester. Thus, 2,3-dibromopropyl 2,3,3,3-tetrafluoropropionate was isolated in 52% yield from the reaction of 2,3-dibromo-1-propanol with PPDA. With a monosubstituted glycerol, a cyclic adduct was obtained. Thus, 4-allyloxymethyl-2-diethylamino-2-(1,2,2,2-tetrafluoroethyl)-1,3-dioxolane was isolated in 68% yield from 3-allyloxy-1,2-propanediol and PPDA. Shielding by the bromine atoms in the former reaction and intramolecular nucleophilic attack by the vicinal hydroxyl group in the latter reaction are possible explanations for the reaction results.