There are numbers of ways to do this.
You can upload them using a csv file; you go to the DB sort the titles by anything u’ll remember, say “date” copy all lof it in order of sorting to your excel, map each one of the slug to each product’s unique ID and upload it back to the DB.
Another way is to set up a backend workflow to make this happen, much easier but WU (if you entries are much of course) …
Set up a “new database trigger”
type =product
Action; set a thing slug -
Things to change =product before change
Slug= products title