(11bS)-3,5-Bis(3,5-di-tert-butylbenzyl)-4,5-dihydro-3H-dinaphtho[2,1-d:1',2'-f][1,3,2]diazaphosphepine 4-oxide

(11bS)-3,5-Bis(3,5-di-tert-butylbenzyl)-4,5-dihydro-3H-dinaphtho[2,1-d:1',2'-f][1,3,2]diazaphosphepine 4-oxide