Reactions involving fluoride ion. Part V. Synthesis of perfluoroisopropylquinolines
Abstract
Fluoride-ion-induced reaction of hexafluoropropene with perfluoroquinoline gives a mixture of perfluoroisopropyl-quinolines. Substitution occurs preferentially in the 2- and 4-positions, and is followed by attack at the 6-position. Rearrangement of perfluoro-2,4-di-isopropylquinoline occurs on heating with fluoride ion, giving the 2,6-isomer as well as other products. Unusually large ‘through-space’ coupling constants, between a 4-perfluoroisopropyl group and a 5-fluorine atom, are observed in the 19F n.m.r. spectra of these systems. Also, the fluorine n.m.r. spectra are temperature dependent and this phenomenon is discussed in terms of preferential population of particular conformations.