Trifluormethylketones are strong serine protease inhibitors; the serine adds into the electrophilic carbonyl group and the result is something that mimics the first tetrahedral intermediate, with a negative charge on the oxygen atom. Look for papers by Robert H. Abeles or Perry Frey in Biochemistry. This is a little different from what you are describing, but a ketone that has two alpha fluorine atoms should still be fairly electrophilic, I suppose.