Baby gate the entrance to his room to start with. I know these things are pain in the butts but (especially because the cat is declawed) it will create a safe place for the cat to go). Once the cat gets settled in there then you can open the door so they can see each other. If Sahara can jump one gate then make it two, this is best for the safety of both dog and cat. Again it will create a HUGE inconvenience but for saftey and sanity it it the best thing.
I really think its just a dog thing to chase cats no matter what. I say this because I do have a cat but Reggie will still chase a cat if its outside and runs.
Next does Sahara know the "leave it" command? If so start strengthening it it, if not start doing it. Here is how I as taught the command.
Take two DIFFERENT treats and but one in each hand and cup them (to avoid stealing) and hold them out in front of you. What ever hand she goes to (lets say left) first tell her "leave it" if she goes back to the same hand say it again. When she moves to the right hand immediately say "take it" at the same time giving up the treat. Repeat several times using the left hand as the "leave it" and the right as the "take it" then break for a bit and switch hands. Its a great mental simulation for the dogs and can be done anywhere and time, and its best to do in 5-10 minute intervals. The reason I say two different treats is so they don't smell the same and confuse the dog. Also the command of "leave it" means the dog CANNOT have what you tell them to "leave", under no circumstances should they take what you tell them to leave. Of course in the beginning they will, but it's one of the most important commands to teach your pet because you never know what they will want to put in their mouth.
So after she's got the treat part down you can move on to the cat part, tell her "leave it" when interested in the cat and give her something else to entertain herself using the command "take it". It might take quite some time with this so have lots of patients. And make sure in the end that cat has a safe place to escape to.