Two men and a boy were reportedly arrested Wednesday after leading cops on a car chase that ended in a tangled mess of metal on a Hayes Valley street corner. The suspects had allegedly stolen someone’s backpack before the chase, which ended at the corner of Buchanan and Hayes streets about 5 p.m. when their Mercedes SUV slammed into a beige van, sending the driver of that vehicle to the hospital, witnesses said. The suspects also hit two other vehicles before coming to a stop. Witnesses said a child at a nearby playground was injured by debris from the crash, and both adult male suspects were hospitalized.