Thanks. Actually I want to link a diketone to carboxylic end of a compound with specific substitution of the hydrogen on the hydroxyl end and establishing a C-O bond.
You could try by SN reaction between your carboxylate (sodium, p.ex.) and the corresponding alpha-haloketone derivative, trying potassium iodide as catalyst. I've performed this reaction several times, but using alkyl halides instead of haloketones, but it could work... Another suggestion is the reaction of the acyl chloride of your acid with the alpha-hydroxyketone derivative of your compound. Maybe this could be the metter option...