Fluoroalkanes, decomposition

The dynamical theory has satisfactorily reproduced the proportions of reverse critical energy partitioned into translation in the elimination of HF from the molecular ions of a number of fluoroalkanes and fluoro-alkenes [167], One broad conclusion was that, in the decompositions studied, late transition states tended to favour partition of reverse critical energy into translation, whereas early transition states did not, cf. late and early downhill [285] (see Sect. 8.4.2). Constraints due to conservation of angular momentum were also evident. 

Fluoroalkanes can be obtained by fluoride transfer from complex fluoride anions to carbocat-ions in the nitrosative decomposition of certain aliphatic azides. Several complex nitrosonium salts, such as NO " BF4, NO PF(, , and NO ShF ". " have been used for this purpose. This reaction is similar to the decomposition of arenediazonium tetrafluoroborate salts to form aryl fluorides (the Balz-Schiemann reaction, discussed in Sections 1.1.8.5. and Vol. F 10a, p686ff). in which fluoride is transferred from a very weak nucleophile, such as the complex tetrafluoroborate anion, to an electron-deficient center. 

Fluoroalkanes by Nitrosative Decomposition of Aliphatic Azides with Complex Nitrosonium Fluorides General Procedure 18... 

Fluoroalkyl groups are easily removed from tin by aqueous base (46, 73-75). Fluoroform is liberated quantitatively when trimethylperfluoromethyltin is treated with aqueous alkali in the cold (77). Even hot water will produce monohydro-perfluoroalkanes from the perfluoroalkyltin compounds. A similar easy hydrolysis to afford monohydro-perfluoroalkanes occurs with perfluoroalkyllead, -germanium, and -antimony compounds. Moreover, fluoroalkyl derivatives of transition metals are also very easily decomposed by aqueous alkali, but fluoroalkanes are not a principal decomposition product (Section VI). 

---