There is no prohibition against hiring turboprop pilots into jets in the U.S.
But there's a balance, companies that have a healthy pool of applicants will require more experience if they're a start-up company or an established company hiring DECS.
Getting hired by a major airline with just turboprop time is very feasible. If the other pieces of your resume are there, except you have tprop time instead of jet time, you'll be competitive.