(11bR)-4-mercapto-2,6-bis[2,4,6-tris(1-methylethyl)phenyl]-4-oxide-dinaphtho[2,1-d:1',2'f][1,3,2]dioxaphosphepin

(11bR)-4-mercapto-2,6-bis[2,4,6-tris(1-methylethyl)phenyl]-4-oxide-dinaphtho[2,1-d:1',2'f][1,3,2]dioxaphosphepin