Preheat the oven to 350 F. Core and peel the apples, and slice into 8 wedges.
Wrap each apple in a crescent roll triangular dough piece. Start at the pointed end, and roll the apple up to the flat end. Pinch in the sides to loosely seal, and place in a 9-x13-inch baking dish that has been sprayed with cooking spray.
Put the butter in a medium pot, and bring to medium heat. When it's melted, add the sugar and cinnamon. Stir and cook on low for 5 minutes, until the sugar is dissolved.
Pour the melted butter mixture over the crescent rolls, and bake for 30 minutes. Serve warm.