Cut pineapple crosswise into six 2 cm-thick slices. Stir together butter, brown sugar and curry powder. Grill pineapple slices on an uncovered grill directly over medium coals for 6 to 8 minutes or till heated through, turning once and brushing once or twice with butter mixture. Combine yogurt and coconut. To serve, cut pineapple slices in half. Serve warm with yogurt.