John Stewart Moilliet

Elemental fluorine. Part 14.1 Electrophilic fluorination and nitrogen functionalisation of hydrocarbons

Selective fluorination of a range of hydrocarbons was achieved by reaction with either elemental fluorine or Selectfluor™, an electrophilic fluorinating reagent of the N–F class. An electrophilic mechanism is envisaged. On prolonged reaction, the strongly acidic reaction medium that is formed upon substitution of hydrogen by fluorine when Selectfluor™ is used as the fluorinating reagent, promotes loss of fluoride from the initial fluorinated product. Trapping of the subsequent carbocation by the acetonitrile solvent in a Ritter type process gives overall nitrogen functionalisation of hydrocarbons. Amidation of hydrocarbons could also be achieved in a one-stage process by reaction of the hydrocarbon with fluorine and a Lewis acid, such as boron trifluoride–diethyl ether, in acetonitrile.

Reactions involving fluoride ion. Part 23. Thermolytic defluorination of perfluoroalkenes in the synthesis of fluorinated dienes and cyclobutenes

Passage of perfluoro-3,4-dimethylhex-3-ene over iron or platinum at elevated temperatures leads to defluorination and fragmentation, giving fluorinated dienes, e.g. perfluoro-2,3-dimethylbutadiene (over Pt) and perfluoro-3,4-dimethylhexa-2,4-diene (over Fe), together with other products. Similar reactions occur with other fluorinated alkenes and the variation between fragmentation and defluorination is rationalised on the basis of the metal used, etc. The fluoride induced reaction between perfluoropropene and perfluorobut-2-ene gives perfluoro-2,3-dimethylpent-2-ene.

Synthesis of fluorinated dienes and cyclobutenes

Pyrolysis of some fluorinated alkenes over platinum or iron, gives good yields of dienes and fluorinated furan derivatives.