(11bR)-2,6-Di([1,1'-biphenyl]-4-yl)-4-hydroxydinaphtho[2,1-d:1',2'-f][1,3,2]dioxaphosphepine 4-oxide

(11bR)-2,6-Di([1,1'-biphenyl]-4-yl)-4-hydroxydinaphtho[2,1-d:1',2'-f][1,3,2]dioxaphosphepine 4-oxide,