Combine the olive oil, vinegar, prunes, olives, capers, bay leaves, garlic, oregano, 2 tablespoons salt, and 2 teaspoons pepper in a large bowl. Add the chicken to the marinade. (You can also place the chicken and marinade in a 2-gallon plastic storage bag and squeeze out the air to make sure the chicken is fully covered with the marinade.) Refrigerate overnight, turning occasionally to be sure the marinade is getting into all of the chicken pieces.
Preheat the oven to 350 degrees F.
Place the chicken, skin side up, along with the marinade in one layer in a large (15-by-18-inch) roasting pan, sprinkle with the brown sugar, 2 teaspoons salt, and 1 teaspoon pepper, and pour the wine around (not over!) the chicken. Roast for 45 to 55 minutes, until the internal temperature of the chicken is 145 degrees F. Remove the pan from the oven, cover tightly with aluminum foil, and allow to rest for 10 to 15 minutes. Discard the bay leaves. Transfer the chicken, prunes, and olives to a serving platter, sprinkle with salt, and serve hot with the pan juices.