Fluorocarbon-aluminium compounds. V. Reactions of some fluorotoluene compounds with lithium tetrahydroaluminate.

In tetrahydrofuran at -45 and in diethyl ether at 20, the reaction of α-bromo- 2,3,4,5,6-pentafluorotoluene with lithium tetrahydroaluminate yields 2,3,4,5,6-penta-fluorotoluene. In tetrahydrofuran at 20, the same reaction occurs initially but the pentafluorotoluene then reacts further with LiAlH4. LiAlH4 attacks the para-fluorine atom of 2,3,4,5,6- pentafluorotoluene to form 2,3,5,6-tetrafluorotoluene and the fluoro- carbon-alane complex LiAl(C6F4CH3)H2F. The reaction between LiAlH4 and C6F5CH3 is complete after 0.5 hr at 65. In turn, 2,3,5,6- tetrafluorotoluene reacts with LiAlH4 in refluxing tetrahydrofuran to form the fluorocarbon-alane complexes LiAl(C6F4CH3)nH4-n, n = 1-3. The fluorocarbon-aluminium compounds have not been isolated from solution but were characterized by quantitative determination of the products of hydrolysis and by 1H and 19F N.M.R. spectroscopy.