Preheat oven to 350 F. Coat a 13"x9" baking dish with cooking spray.
Place chicken in baking dish.
In a small saucepan, combine wine and prunes. Cook on medium-high heat until wine boils. Pour over chicken. Sprinkle with rosemary, salt and pepper.
Bake for 30 minutes or until thermometer inserted in thickest portion register 160 F and juices run clear.