Grilled Pork Tenderloin with Orange-Chipotle Sauce

3 1/2 pounds pork tenderloins

6 cups orange juice, divided

2 teaspoons salt

2 tablespoons butter

3 large shallots, finely chopped

1 cup dry white wine

2 3/4 cups low-salt chicken broth

2 Tablespoons chopped fresh cilantro

1 Tablespoon chopped fresh chives

1 Tablespoon minced canned chipotle chiles in adobe

Divide pork between 2 resealable plastic bags. Add 1 cup orange juice and 1 teaspoon salt to each bag; seal. Turn to coat. Chill at least 3 hours or overnight, turning bags occasionally.

Melt butter in heavy large saucepan over medium high heat. Add shallots and saute until soft but not brown, about 2 minutes. Add wine and boil until reduced to glaze, about 10 minutes. Add remaining 4 cups orange juice and broth; boil until reduced to 1 3/4 cups, about 45 minutes. (Sauce can be made 1 day ahead. Cool, then cover and chill.)

Prepare barbecue (medium-hight heat). Drain pork; pat dry. Discard marinade. Grill pork until thermometer inserted into thickest part of meat registers 150 degrees F for medium, turning often, about 18 minutes. Transfer to work surface; tent with aluminum foil to keep warm. Let stand 10 minutes.

Meanwhile bring sauce to simmer; mix in cilantro, chives, and chipotle chiles. Season sauce to taste with salt and pepper. Slice pork. Serve with sauce