Pre-heat oven to 450 ⁰F (230⁰C).
Take the duck out of the package, empty the cavity and rinse under cold water and pat dry. Cut off excess fat from the ends. Using a bamboo skewer, prick the skin of the duck on top and underneath (on the fatty parts), without piercing the meat. Season the duck with salt on the outside and inside the cavity. Stuff the duck with 2 sprigs of fresh thyme, the garlic and clementine or mandarin quarters, and then truss. Place the duck, breast side down, on a grill in an approximately 13 x 9 in broiling pan. Place in the oven (uncover) and roast for 30 min. Reduce the temperature to 350 ⁰F (175⁰C) turn the duck over to breast side up, and roast for another 30 minutes.
In the meantime, put the wine, grapes, 1 sprig of thyme and jelly in a small saucepan, and bring to a boil. Reduce to half over medium heat. Season with salt and pepper. Add 1 tbsp. of maple syrup, or more to taste. Mix. Set aside.
Take the duck out of the oven, and baste with the fat and cooking juices. Put the duck back in the oven and continue cooking until the skin turns golden brown, approximately 60 minutes, baste regularly.
Take the duck out of the broiling pan. Mix the soy sauce and maple syrup and then brush the mixture over the duck. Return to the oven and cook for another 10 minutes. Empty the accumulated fat. Tilt the duck to empty the cooking juices that have accumulated in the cavity. Skim off the juice and add to the compote. Transfer the duck to a serving plate. Remove string and leave to rest for 15 minutes. Slice and serve with the sauce on the side.