(11bS)-2 – 6-Bis[4-(2-naphthalenyl)phenyl]-8 – 9 – 10 – 11 – 12 – 13 – 14 – 15-octahydro-4-hydroxy-4-oxide-dinaphtho[2 – 1-d:1′ – 2′-f][1 – 3 – 2]dioxaphosphepin