Optically active 1,1'-biphenanthryl-2,2'-diol, process for preparing the same, and resolving reagent comprising the same

The novel optically active 1,1'-biphenanthryl-2,2'-diol is disclosed, which is obtained by preparing N((S)-1-phenylethyl)-1,1'-biphenanthryl-2,2'-diylthiophosphorylamide by using optically active phenylethylamine, recrystallizing the compound into an optically active compound, followed by reduction with a reducing agent. The diol compound according to the present invention is useful as a resolving reagent, a starting material of an optically active phosphine compound or a ligand in asymmetric synthesis, forming a complex with a transition metal or a rare earth element to provide a useful catalyst.