Pour warm water into a bowl; add yeast and let stand until creamy, about 10 minutes.

Combine yeast mixture, cake mix, and 3 cups of flour in a large bowl; stir well. Add remaining flour, 1/2 cup at a time, stirring well after each addition until dough pulls together. Turn dough out onto a lightly floured surface and knead until smooth and elastic, about 8 minutes.

Lightly oil a large bowl; place dough in the bowl and turn to coat with oil. Cover with a damp cloth and let rise in a warm place until doubled in volume, about 30 minutes.

Deflate dough and turn it out onto a lightly floured surface. Roll the dough into a 10x16-inch rectangle. Spread softened butter over the rectangle; sprinkle on brown sugar and cinnamon. Starting from one of the long sides, roll up the rectangle and cut into 1-inch wide rolls.

Preheat the oven to 375 degrees F (190 degrees C). Grease a 9x13-inch baking pan.

Pour melted butter into a small bowl. Mix the white sugar and pecans in another small bowl. Dip the top of each roll in melted butter, then in sugar and pecan mixture, then arrange rolls snugly in the prepared pan. Cover rolls with a damp cloth and let rise until doubled in volume, about 30 minutes.

Bake in the preheated oven until golden brown, about 20 minutes.