The addition of (pentafluoroethyl)- and (heptafluoropropyl)lithium to various acyl derivatives was studied. Weinreb and morpholine amides led to polyfluoro ketones in high to quantitative yields in short reaction times. Derivatives of 2-fluorocarboxylic acids may produce 1,1,1,2,2,4-hexafluoro ketones and 1,1,1,2,2,3,3,5-octafluoro ketones. The methodology can provide inhibitors for various lipolytic enzymes, including phospholipase A2.