REACTION OF (POLYFLUOROALKYL)TRIMETHYLAMMONIUM SALTS WITH HYDROXIDE ION

(Polyfluoroalkyl)trimethylammonium iodides (1a-d), R(f)CF2CH2N+Me3I- (R(f), a = HCF2, b = CF3, c = H(CF2)3, d = H(CF2)5), reacted easily with an equimolar amount of sodium hydroxide in water at 20-degrees-C to give Z isomers of (polyfluoro-1-alkenyl)trimethylammonium iodides (2a-d), R(f)CF=CHN+Me3I-, quantitatively. However, treatment of 1 with 3 equimolar amounts of sodium hydroxide yielded different products depending on the length of the R(f) chain: 1a gave (2-oxo-3,3-difluoropropyl)trimethylammonium iodide (3a), which had a great tendency to form the hydrate 4a; 1b produced a mixture of the analogous ketone 3b and betaine 6; 1c and 1d afforded the corresponding 1H,omega-H-perfluoroalkanes 7c and 7d, respectively, together with 6.