(S)-1-{(S)-2-[2-[DI(3,5-XYLYL)PHOSPHINO]PHENYL]FERROCENYL}ETHYLDI(3,5-XYLYL)PHOS;(S)-1-{(SP)-2-[2-[Di(3,5-xylyl)phosphino]phenyl]ferrocenyl}ethyldi(3,5-xylyl)phosphine;(S)-1-[(Sp)-1-[Di(3,5-xylyl)phosphino]ethyl]-2-[2-[di(3,5-xylyl)phosphino]phenyl]ferrocene;(S)-1-[(S)-1-[Di(3,5-xylyl)phosphino]ethyl]-2-[2-[di(3,5-xylyl) phosphino]phenyl]ferrocene;(s,s)-1-{1-[bis(3,5-dimethylphenyl)phosphino]ethyl}-2-{2-[bis(3,5-dimethylphenyl)phosphino]phenyl}ferrocene (acc to cas)