Preheat oven to 450F. Mince 2 each garlic cloves and combine in a small bowl with 1/4 cup oil, 1 Tbsp oregano, 1/2 tsp salt and 1/4 tsp pepper.
Halve the remaining garlic and toss with Brussels sprouts and 3 tablespoons of the seasoned oil in a large roasting pan. Roast, stirring once, for 15 minutes. Add wine to the remaining seasoned oil mixture. Remove the pan from oven, stir the vegetables and place salmon (cut into 6 portions) on top. Drizzle with the wine mixture. Sprinkle with the remaining oregano and salt and pepper. Bake until the salmon is just cooked through, 5 to 10 minutes more. Serve with lemon wedges.