The synthesis of α-N,N-dimethyl-1′-diphenylphosphinoferrocenylethylamine and related ligands

Routes to the title compound were explored based on the cleavage of [1]-ferrocenophanes with aryllithium. Thus the cleavage of [Formula: see text] with phenyllithium affords (η 5 -C 5 H 4 Li)Fe(η 5 -C 5 H 3 (CHMeNMe 2 )PPh 2 ) and η 5 -C 5 H 4 PPh 2 )Fe(η 5 -C 5 H 3 Li(CHMeNMe 2 )) in the ratio 15:85. Hydrolysis of this mixture affords the title compound 4. The lithio-ferrocenes can be treated with XER 2 to yield other mixed ligands (E = As, P).A route to 4 via (η 5 -C 5 H 4 PPh 2 )Fe(η 5 -C 5 H 4 C(O)Me) was also established but it is complicated by low yields and many side products such as [(η 5 -C 5 H 4 PPh 2 )Fe(η 5 -C 5 H 4 )] 2 C=CH 2 .