WASHINGTON, D.C (AP).- Whoopi Goldberg, John Legend, Sean Combs and Serena Williams now have a place in the National Portrait Gallery in a show opening Friday, along with other leading black figures who may be lesser known. “The Black List” features 50 large-scale photographs from Timothy Greenfield-Sanders in a project that also included a 2008 HBO film. After a conversation with his friend, the writer Toni Morrison, Greenfield-Sanders began thinking of all the successful black figures he knows — and how so many were unknown. He and collaborator Elvis Mitchell scribbled down 200 names on napkins over lunch. “I’ve done the art world, I’ve done the music world, I’ve done the porn world, I’ve done politics —