An ether solution of methyl lithium (70 cc, containing 21 g of methyl lithium) was added to hexafluorobenzene (20 g) in dry ether (20 cc) at a rate sufficient to maintain mild reflux, stirred, and after addition and addition of water (100 cc), stirring was maintained for one hour. The ether layer was dried (MgSO4), filtered, and most of the ether was distilled off through a 6-inch column to separate the residual liquid (17 g), which was passed through a gas chromatograph 100 (column 488 cm x 75 mm, packed with silicone rubber/ diatomaceous earth 1:3, temperature 1000°C, no flow rate 451/hr) to give 2,3,4,5,6-pentafluorotoluene (138 g). Reaction with one molecular equivalent of sulfonyl chloride then halogenates the methyl in the presence of 0005 molecular equivalents of dibenzoyl peroxide The major product is 2,3,4,5,6-pentafluorobenzyl chloride with a boiling point of 88-90°C and a mercury pressure of 69 mm.
