Kitty's Leather Couch

Kitty has demolished our leather couch. We're thinking about buying another leather couch. We won't declaw and he won't wear mittens. Kitty, at five years of age, will probably always like scratching leather.

We used to have a scratching post, but he never took to it. We may keep the old couch for him to continue to scratch, but we want to be sure that he doesn't ruin the new couch.
I'm interested in hearing of cat-friendly ideas on how to protect our furniture. For example, are there any feline-repelling (but that don't repel human) sprays on the market?

Consistent training will teach him to leave the couch alone. The idea is to make the couch an unpleasant choice to scratch while making vertical or horizontal scratching posts desirable. Things that will make the couch unpleasant are tape, sticky side up, getting squirted with water if he starts to scratch, a loud noise to startle him.

It sounds like what basically is needed is behavorial conditioning. An example is what we inflict on Kitty each night when my wife makes my sandwich for work to our general delight. He gets a nice slice of ham but only if he walks on his two back feet. Kitty is turning into a regular Puss in Boots by the way he toddles around the kitchen. The principle is the same with the couch I suppose, but using rocks in a can or a water-bottle to reinforce a different kind of behavior.

We'll see if it works.