To my ear, in American English I’d opt for:
The money paid to professional sportsmen puts them on a list of the wealthiest men in the world, alongside businessmen and entrepreneurs.
In addition to the use of “alongside,” I’d pick this construction because:
- Salaries are paid or earned, rather than simply given (in the sense of a gift).
- You’re making a list, as the sentence refers to an abstract or conceptual list rather than a singular, definitive list such as the Forbes Annual List of Billionaires.
- Which list, and who else is on the list, seem like they should be distinct sentence clauses. Hence the added comma.
Note that word choice is often subjective, but “alongside” definitely sound more natural to me than “side by side with.”