I always tell my child that he can go to his favorite extracurricular activity after he finishes his homework and that always works! For e.g. "we can head out to your swimming practice after you finish your homework and the only thing keeping you home right now is your unfinished homework!" and my child's response usually is to tear through his homework in minutes and get ready to leave.
So, give him something to look forward to "after" finishing the homework. Find out what his currency is and negotiate - for e.g. you can go out with mom after the homework or you can get your screen time after homework or you can play with your favorite toy after you finish your work. Do not negotiate with him on when/if he needs to do his homework - just let him know that he gets to earn some extra privileges which he really wants by doing the expected tasks on schedule.
