(11aS)-10,11,12,13-Tetrahydro-5-hydroxy-3,7-bis[2,4,6-trisisopropylphenyl]-5-oxide-diindeno[7,1-de 1 ,7 -fg][1,3,2]dioxaphosphocin (11aS)-10,11,12,13-Tetrahydro-5-hydroxy-3,7-bis[2,4,6-trisisopropylphenyl]-5-oxide-diindeno[7,1-de 1 ,7 -fg][1,3,2]dioxaphosphocin