Sprinkle pecans evenly onto bottom of well-greased fluted tube pan.
Place cake mix, eggs, sour cream, 1/2 cup of the rum and oil in large bowl; beat with electric mixer on medium speed 2 min. or until well blended.
Pour into prepared pan.
Bake 1 hour or until toothpick inserted near center of cake comes out clean; cool cake 10 min. in pan on wire rack.
Remove cake from pan; cool completely.
Place sugar, butter and 2 Tbsp. water in small saucepan; bring to boil on medium heat, stirring frequently. Gradually add remaining 1/4 cup rum, stirring until well blended.