(11bR)-2,6-Bis[3,5-bis(1,1-dimethylethyl)-4-methoxyphenyl]-4-hydroxy-4-oxide-dinaphtho[2,1-d:1',2'-f][1,3,2]dioxaphosphepin

(11bR)-2,6-Bis[3,5-bis(1,1-dimethylethyl)-4-methoxyphenyl]-4-hydroxy-4-oxide-dinaphtho[2,1-d:1',2'-f][1,3,2]dioxaphosphepin,