The alpha-position of an acetophenone is more reactive than the 4-position of the aromatic ring, so with carefully selected reaction conditions, it is possible to selectively brominate there with NBS as far as I know. If that is not possible to control enough, then CuBr2 can brominate acetophenones without any effect on the ring.
1,1-Difluoroalkylbenzenes are made by treating the corresponding carbonyl compound with DAST (diethylaminosulfur tetrafluoride).
I don't have any references handy, but do a search on gem-difluorides on http://www.scirus.com (http://www.scirus.com)
Preparation of 3-Trifluoromethyl-?,?,?-trifluoroacetophenone
Patent US3748361 (http://l2.espacenet.com/dips/viewer?PN=US3748361&CY=gb&LG=en&DB=EPD)
50.5 g (2.1 moles) of magnesium turnings were charged to a 2 liter flask fitted with a mechanical stirrer, reflux condenser, addition tube and thermometer. One ml of ethyl bromide in 50 ml. ether was added as an activator. 450 g (2.0 moles) of meta trifluoromethyl bromobenzene in 1200 ml of ether were added dropwise to the magnesium. The addition time was 5 hrs. The temperature was maintained between 25-30°C. To this dark reaction mixture were added 76 g (0.66 mole) of trifluoroacetic acid in 750 ml of anhydrous ether over a two-hour period. The reaction temperature was 35°C. The reaction mixture was then refluxed for 2 hours after addition was complete and cooled to 0°C.; then 100 ml of H2O were added to the mixture slowly, followed by 200 ml of concentrated HCl dissolved in 300 ml. of H2O. The temperature was maintained between 0-10°C.
The. ether layer was separated and washed twice with 10% Na2CO3 solution. The ether layer was then dried over anhydrous MgSO4, filtered, and the filtrate concentrated on a roto-evaporator. The residue was vacuum distilled at 89°C/80mmHg to give 119 g (85%) of the ketone and then analyzed.