Four words
Copper plate.
Extension cord.
Actually, though I don't think you'll want to hear it, I doubt you'll be able to break him of it. If he's declawed he's an indoor-only cat, right? The smaller a cat's range is, the more territorial he gets about it.
Pregnant cats nearing delivery reduce thier range to a couple of square feet, but will kill dogs several times thier size who enter. Outdoor cats will let other cats pass through thier yard, but won't let them stay.
Probably your only bet is to convince the cat that the dining room is your range, and he's not welcome to claim it. How you do that is left for the reader.
